6e91fda7fd
Replace eager Dictionary<ulong, StoredMessage> with lightweight Dictionary<ulong, MessageMeta> to eliminate ~200B StoredMessage allocation per message on the write path. - Add MessageMeta struct (BlockId, Subject, PayloadLength, HeaderLength, TimestampNs) — ~40B vs ~200B for StoredMessage - Add MaterializeMessage(seq) for on-demand reconstruction from blocks - Update all ~60 _messages references to use _meta - Methods needing full payload (LoadAsync, ListAsync, etc.) call MaterializeMessage; metadata-only paths use _meta directly - Fix MsgBlock.WriteAt to clear stale delete markers on re-write
2760 lines
103 KiB
C#
2760 lines
103 KiB
C#
using System.Buffers.Binary;
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using System.Collections.Concurrent;
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using System.Security.Cryptography;
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using System.Text;
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using System.Text.Json;
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using System.Threading.Channels;
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using NATS.Server.JetStream.Models;
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using NATS.Server.Internal.TimeHashWheel;
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// Storage.StreamState is in this namespace. Use an alias for the API-layer type
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// (now named ApiStreamState in the Models namespace) to keep method signatures clear.
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using ApiStreamState = NATS.Server.JetStream.Models.ApiStreamState;
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namespace NATS.Server.JetStream.Storage;
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/// <summary>
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/// Block-based file store for JetStream messages. Uses <see cref="MsgBlock"/> for
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/// on-disk persistence and maintains an in-memory cache (<see cref="StoredMessage"/>)
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/// for fast reads and subject queries.
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///
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/// Reference: golang/nats-server/server/filestore.go — block manager, block rotation,
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/// recovery via scanning .blk files, soft-delete via dmap.
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/// </summary>
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public sealed class FileStore : IStreamStore, IAsyncDisposable, IDisposable
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{
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private readonly FileStoreOptions _options;
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// Lightweight metadata index: keyed by sequence number. Stores only the fields
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// needed for existence checks, subject queries, and timestamp lookups.
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// Full message payloads are materialized on demand from blocks via MaterializeMessage.
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private readonly Dictionary<ulong, MessageMeta> _meta = new();
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/// <summary>
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/// Lightweight per-message metadata stored in the in-memory index.
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/// Eliminates the ~200B StoredMessage allocation on the write path.
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/// </summary>
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private struct MessageMeta
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{
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public int BlockId;
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public string Subject;
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public int PayloadLength;
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public int HeaderLength;
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public long TimestampNs;
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}
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private readonly Dictionary<string, ulong> _lastSequenceBySubject = new(StringComparer.Ordinal);
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// Block-based storage: the active (writable) block and sealed blocks.
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private readonly List<MsgBlock> _blocks = [];
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private MsgBlock? _activeBlock;
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private int _nextBlockId;
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private ulong _last;
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private ulong _first; // Go: first.seq — watermark for the first live or expected-first sequence
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// Incremental state tracking — avoid O(n) scans in GetStateAsync/FastState.
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// Updated in AppendAsync, StoreMsg, RemoveAsync, PurgeAsync, PurgeEx, Compact,
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// Truncate, TrimToMaxMessages, EnforceMaxMsgsPerSubject, and recovery.
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private ulong _messageCount;
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private ulong _totalBytes;
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private ulong _firstSeq;
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// Set to true after Stop() is called. Prevents further writes.
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private bool _stopped;
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// Resolved at construction time: which format family to use.
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private readonly bool _useS2; // true -> S2Codec (FSV2 compression path)
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private readonly bool _useAead; // true -> AeadEncryptor (FSV2 encryption path)
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private readonly bool _noTransform; // true -> no compression/encryption, TransformForPersist just copies
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// Go: filestore.go — per-stream time hash wheel for efficient TTL expiration.
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// Created lazily only when MaxAgeMs > 0. Entries are (seq, expires_ns) pairs.
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// Reference: golang/nats-server/server/filestore.go:290 (fss/ttl fields).
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private HashWheel? _ttlWheel;
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// Mutual-exclusion lock for state file writes. Ensures that concurrent
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// FlushAllPending calls (e.g. from a flush timer and a shutdown path) do not
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// race on the stream.state / stream.state.tmp files.
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// Reference: golang/nats-server/server/filestore.go — fsMsgBlock.mu (write lock).
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private readonly SemaphoreSlim _stateWriteLock = new(1, 1);
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// Go: filestore.go:4443 (setupWriteCache) — bounded write cache manager.
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// Manages TTL-based expiry and size cap across all active blocks.
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// Reference: golang/nats-server/server/filestore.go:6148 (expireCache).
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private readonly WriteCacheManager _writeCache;
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// Go: filestore.go:5841 — background flush loop coalesces buffered writes.
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// Reference: golang/nats-server/server/filestore.go:328-331 (coalesce constants).
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private readonly Channel<byte> _flushSignal = Channel.CreateBounded<byte>(1);
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private readonly CancellationTokenSource _flushCts = new();
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private Task? _flushTask;
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private const int CoalesceMinimum = 16 * 1024; // 16KB — Go: filestore.go:328
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private const int MaxFlushWaitMs = 8; // 8ms — Go: filestore.go:331
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// Go: filestore.go — generation counter for cache invalidation.
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// Incremented on every write (Append/StoreRawMsg) and delete (Remove/Purge/Compact).
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// NumFiltered caches results keyed by (filter, generation) so repeated calls for
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// the same filter within the same generation are O(1).
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// Reference: golang/nats-server/server/filestore.go — fss generation tracking.
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private ulong _generation;
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private readonly Dictionary<string, (ulong Generation, ulong Count)> _numFilteredCache = new(StringComparer.Ordinal);
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public int BlockCount => _blocks.Count;
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public bool UsedIndexManifestOnStartup { get; private set; }
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// IStreamStore cached state properties — O(1), maintained incrementally.
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public ulong LastSeq => _last;
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public ulong MessageCount => _messageCount;
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public ulong TotalBytes => _totalBytes;
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ulong IStreamStore.FirstSeq => _messageCount == 0 ? (_first > 0 ? _first : 0UL) : _firstSeq;
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public FileStore(FileStoreOptions options)
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{
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_options = options;
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if (_options.BlockSizeBytes <= 0)
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_options.BlockSizeBytes = 64 * 1024;
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// Determine which format path is active.
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_useS2 = _options.Compression == StoreCompression.S2Compression;
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_useAead = _options.Cipher != StoreCipher.NoCipher;
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_noTransform = !_useS2 && !_useAead && !_options.EnableCompression && !_options.EnableEncryption;
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Directory.CreateDirectory(options.Directory);
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// Attempt legacy JSONL migration first, then recover from blocks.
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MigrateLegacyJsonl();
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RecoverBlocks();
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// Go: filestore.go:4443 (setupWriteCache) — initialise the bounded cache manager.
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// Reference: golang/nats-server/server/filestore.go:6148 (expireCache).
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_writeCache = new WriteCacheManager(
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_options.MaxCacheSize,
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_options.CacheExpiry,
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blockId => _blocks.Find(b => b.BlockId == blockId));
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// Go: filestore.go:5841 — start background flush loop for write coalescing.
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_flushTask = Task.Run(() => FlushLoopAsync(_flushCts.Token));
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}
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public ValueTask<ulong> AppendAsync(string subject, ReadOnlyMemory<byte> payload, CancellationToken ct)
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{
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if (_stopped)
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throw new ObjectDisposedException(nameof(FileStore), "Store has been stopped.");
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// Go: DiscardNew — reject when MaxBytes would be exceeded.
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if (_options.MaxBytes > 0 && _options.Discard == DiscardPolicy.New
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&& (long)_totalBytes + payload.Length > _options.MaxBytes)
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{
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throw new StoreCapacityException("maximum bytes exceeded");
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}
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// Go: check and remove expired messages before each append.
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// Only when MaxAge is configured (Go: filestore.go:4701 conditional).
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if (_options.MaxAgeMs > 0)
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ExpireFromWheel();
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_last++;
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var now = DateTime.UtcNow;
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var timestamp = new DateTimeOffset(now).ToUnixTimeMilliseconds() * 1_000_000L;
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// Go: writeMsgRecordLocked writes directly into mb.cache.buf (a single contiguous
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// byte slice). It does NOT store a per-message object in a map.
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// We store lightweight MessageMeta instead of full StoredMessage to avoid ~200B alloc.
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var persistedPayload = TransformForPersist(payload.Span);
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// Go: register TTL only when TTL > 0.
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if (_options.MaxAgeMs > 0)
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RegisterTtl(_last, timestamp, (long)_options.MaxAgeMs * 1_000_000L);
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// Write to MsgBlock first so we know the block ID for the meta entry.
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EnsureActiveBlock();
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try
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{
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_activeBlock!.WriteAt(_last, subject, ReadOnlyMemory<byte>.Empty, persistedPayload, timestamp);
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}
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catch (InvalidOperationException)
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{
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RotateBlock();
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_activeBlock!.WriteAt(_last, subject, ReadOnlyMemory<byte>.Empty, persistedPayload, timestamp);
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}
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// Track lightweight metadata now that we know the block ID.
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TrackMessage(_last, subject, 0, payload.Length, timestamp, _activeBlock!.BlockId);
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_generation++;
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_writeCache.TrackWrite(_activeBlock!.BlockId, persistedPayload.Length);
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_flushSignal.Writer.TryWrite(0);
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// Check if the block just became sealed after this write.
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if (_activeBlock!.IsSealed)
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RotateBlock();
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// Go: enforce MaxMsgsPerSubject — remove oldest messages for this subject
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// when the per-subject count exceeds the limit.
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// Reference: golang/nats-server/server/filestore.go — enforcePerSubjectLimit.
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if (_options.MaxMsgsPerSubject > 0 && !string.IsNullOrEmpty(subject))
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EnforceMaxMsgsPerSubject(subject);
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return ValueTask.FromResult(_last);
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}
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public ValueTask<StoredMessage?> LoadAsync(ulong sequence, CancellationToken ct)
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{
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return ValueTask.FromResult(MaterializeMessage(sequence));
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}
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public ValueTask<StoredMessage?> LoadLastBySubjectAsync(string subject, CancellationToken ct)
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{
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if (_lastSequenceBySubject.TryGetValue(subject, out var sequence))
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{
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var msg = MaterializeMessage(sequence);
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return ValueTask.FromResult(msg);
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}
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return ValueTask.FromResult<StoredMessage?>(null);
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}
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public ValueTask<IReadOnlyList<StoredMessage>> ListAsync(CancellationToken ct)
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{
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var messages = _meta.Keys
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.OrderBy(seq => seq)
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.Select(seq => MaterializeMessage(seq))
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.Where(m => m is not null)
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.Cast<StoredMessage>()
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.ToArray();
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return ValueTask.FromResult<IReadOnlyList<StoredMessage>>(messages);
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}
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public ValueTask<bool> RemoveAsync(ulong sequence, CancellationToken ct)
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{
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if (!RemoveTrackedMessage(sequence, preserveHighWaterMark: false))
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return ValueTask.FromResult(false);
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_generation++;
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// Soft-delete in the block that contains this sequence.
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DeleteInBlock(sequence);
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return ValueTask.FromResult(true);
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}
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public ValueTask PurgeAsync(CancellationToken ct)
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{
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_meta.Clear();
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_generation++;
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_last = 0;
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_messageCount = 0;
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_totalBytes = 0;
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_firstSeq = 0;
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// Dispose and delete all blocks.
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DisposeAllBlocks();
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CleanBlockFiles();
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// Clean up any legacy files that might still exist.
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var jsonlPath = Path.Combine(_options.Directory, "messages.jsonl");
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if (File.Exists(jsonlPath))
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File.Delete(jsonlPath);
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var manifestPath = Path.Combine(_options.Directory, _options.IndexManifestFileName);
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if (File.Exists(manifestPath))
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File.Delete(manifestPath);
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return ValueTask.CompletedTask;
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}
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public ValueTask<byte[]> CreateSnapshotAsync(CancellationToken ct)
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{
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var snapshot = _meta.Keys
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.OrderBy(seq => seq)
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.Select(seq =>
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{
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var msg = MaterializeMessage(seq);
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if (msg is null) return null;
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return new FileRecord
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{
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Sequence = msg.Sequence,
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Subject = msg.Subject,
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HeadersBase64 = msg.RawHeaders.IsEmpty ? null : Convert.ToBase64String(msg.RawHeaders.Span),
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PayloadBase64 = Convert.ToBase64String(TransformForPersist(msg.Payload.Span)),
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TimestampUtc = msg.TimestampUtc,
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};
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})
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.Where(r => r is not null)
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.ToArray();
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return ValueTask.FromResult(JsonSerializer.SerializeToUtf8Bytes(snapshot));
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}
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public ValueTask RestoreSnapshotAsync(ReadOnlyMemory<byte> snapshot, CancellationToken ct)
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{
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_meta.Clear();
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_lastSequenceBySubject.Clear();
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_last = 0;
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_messageCount = 0;
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_totalBytes = 0;
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_firstSeq = 0;
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_first = 0;
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// Dispose existing blocks and clean files.
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DisposeAllBlocks();
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CleanBlockFiles();
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if (!snapshot.IsEmpty)
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{
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var records = JsonSerializer.Deserialize<FileRecord[]>(snapshot.Span);
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if (records != null)
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{
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foreach (var record in records)
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{
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var restoredHeaders = string.IsNullOrEmpty(record.HeadersBase64)
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? ReadOnlyMemory<byte>.Empty
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: Convert.FromBase64String(record.HeadersBase64);
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var restoredPayload = RestorePayload(Convert.FromBase64String(record.PayloadBase64 ?? string.Empty));
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var persistedPayload = TransformForPersist(restoredPayload);
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var timestampNs = new DateTimeOffset(record.TimestampUtc).ToUnixTimeMilliseconds() * 1_000_000L;
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var subject = record.Subject ?? string.Empty;
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_last = Math.Max(_last, record.Sequence);
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EnsureActiveBlock();
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try
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{
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_activeBlock!.WriteAt(record.Sequence, subject, restoredHeaders, persistedPayload, timestampNs);
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}
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catch (InvalidOperationException)
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{
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RotateBlock();
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_activeBlock!.WriteAt(record.Sequence, subject, restoredHeaders, persistedPayload, timestampNs);
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}
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TrackMessage(record.Sequence, subject, restoredHeaders.Length, restoredPayload.Length, timestampNs, _activeBlock!.BlockId);
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if (_activeBlock!.IsSealed)
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RotateBlock();
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}
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}
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}
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return ValueTask.CompletedTask;
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}
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public ValueTask<ApiStreamState> GetStateAsync(CancellationToken ct)
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{
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return ValueTask.FromResult(new ApiStreamState
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{
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Messages = _messageCount,
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FirstSeq = _messageCount == 0 ? (_first > 0 ? _first : 0UL) : _firstSeq,
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LastSeq = _last,
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Bytes = _totalBytes,
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});
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}
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public void TrimToMaxMessages(ulong maxMessages)
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{
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var trimmed = false;
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while ((ulong)_meta.Count > maxMessages)
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{
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var first = _firstSeq;
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if (first == 0 || !RemoveTrackedMessage(first, preserveHighWaterMark: true))
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break;
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DeleteInBlock(first);
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trimmed = true;
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}
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if (!trimmed)
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return;
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_generation++;
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}
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// -------------------------------------------------------------------------
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// Go-parity sync interface implementations
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// Reference: golang/nats-server/server/filestore.go
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// -------------------------------------------------------------------------
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/// <summary>
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/// Synchronously stores a message, optionally with a per-message TTL override.
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/// Returns the assigned sequence number and timestamp in nanoseconds.
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/// When <paramref name="ttl"/> is greater than zero it overrides MaxAgeMs for
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/// this specific message; otherwise the stream's MaxAgeMs applies.
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/// Reference: golang/nats-server/server/filestore.go:6790 (storeMsg).
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/// </summary>
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public (ulong Seq, long Ts) StoreMsg(string subject, byte[]? hdr, byte[] msg, long ttl)
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{
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if (_stopped)
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throw new ObjectDisposedException(nameof(FileStore), "Store has been stopped.");
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// Go: expire check before each store (same as AppendAsync).
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// Reference: golang/nats-server/server/filestore.go:6793 (expireMsgs call).
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ExpireFromWheel();
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_last++;
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var now = DateTime.UtcNow;
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var timestamp = new DateTimeOffset(now).ToUnixTimeMilliseconds() * 1_000_000L;
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var headers = hdr is { Length: > 0 } ? hdr : [];
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var payload = msg ?? [];
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var persistedPayload = TransformForPersist(payload);
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|
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// Determine effective TTL: per-message ttl (ns) takes priority over MaxAgeMs.
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// Go: filestore.go:6830 — if msg.ttl > 0 use it, else use cfg.MaxAge.
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var effectiveTtlNs = ttl > 0 ? ttl : (_options.MaxAgeMs > 0 ? (long)_options.MaxAgeMs * 1_000_000L : 0L);
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RegisterTtl(_last, timestamp, effectiveTtlNs);
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EnsureActiveBlock();
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try
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{
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_activeBlock!.WriteAt(_last, subject, headers, persistedPayload, timestamp);
|
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}
|
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catch (InvalidOperationException)
|
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{
|
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RotateBlock();
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_activeBlock!.WriteAt(_last, subject, headers, persistedPayload, timestamp);
|
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}
|
||
|
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TrackMessage(_last, subject, headers.Length, payload.Length, timestamp, _activeBlock!.BlockId);
|
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_generation++;
|
||
|
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// Go: filestore.go:4443 (setupWriteCache) — record write in bounded cache manager.
|
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_writeCache.TrackWrite(_activeBlock!.BlockId, headers.Length + persistedPayload.Length);
|
||
|
||
// Signal the background flush loop to coalesce and flush pending writes.
|
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_flushSignal.Writer.TryWrite(0);
|
||
|
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if (_activeBlock!.IsSealed)
|
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RotateBlock();
|
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|
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return (_last, timestamp);
|
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}
|
||
|
||
/// <summary>
|
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/// Removes all messages from the store and returns the count purged.
|
||
/// Reference: golang/nats-server/server/filestore.go — purge / purgeMsgs.
|
||
/// </summary>
|
||
public ulong Purge()
|
||
{
|
||
var count = (ulong)_meta.Count;
|
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_meta.Clear();
|
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_lastSequenceBySubject.Clear();
|
||
_generation++;
|
||
_last = 0;
|
||
_messageCount = 0;
|
||
_totalBytes = 0;
|
||
_firstSeq = 0;
|
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_first = 0;
|
||
|
||
DisposeAllBlocks();
|
||
CleanBlockFiles();
|
||
|
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return count;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Purge messages on a given subject, up to sequence <paramref name="seq"/>,
|
||
/// keeping the newest <paramref name="keep"/> messages.
|
||
/// If subject is empty or null, behaves like <see cref="Purge"/>.
|
||
/// Returns the number of messages removed.
|
||
/// Reference: golang/nats-server/server/filestore.go — PurgeEx.
|
||
/// </summary>
|
||
public ulong PurgeEx(string subject, ulong seq, ulong keep)
|
||
{
|
||
// Go parity: empty subject with keep=0 and seq=0 is a full purge.
|
||
// If keep > 0 or seq > 0, fall through to the candidate-based path
|
||
// treating all messages as candidates.
|
||
if (string.IsNullOrEmpty(subject) && keep == 0 && seq == 0)
|
||
return Purge();
|
||
|
||
var upperBound = seq == 0 ? _last : Math.Min(seq, _last);
|
||
if (upperBound == 0)
|
||
return 0;
|
||
|
||
ulong candidateCount = 0;
|
||
for (var current = _messageCount == 0 ? 0UL : _first; current != 0 && current <= upperBound; current++)
|
||
{
|
||
if (!_meta.TryGetValue(current, out var meta))
|
||
continue;
|
||
|
||
if (!SubjectMatchesFilter(meta.Subject, subject))
|
||
continue;
|
||
|
||
candidateCount++;
|
||
}
|
||
|
||
if (candidateCount == 0)
|
||
return 0;
|
||
|
||
var targetRemoveCount = keep > 0
|
||
? (candidateCount > keep ? candidateCount - keep : 0UL)
|
||
: candidateCount;
|
||
|
||
if (targetRemoveCount == 0)
|
||
return 0;
|
||
|
||
ulong removed = 0;
|
||
for (var current = _messageCount == 0 ? 0UL : _first; current != 0 && current <= upperBound && removed < targetRemoveCount; current++)
|
||
{
|
||
if (!_meta.TryGetValue(current, out var meta2))
|
||
continue;
|
||
|
||
if (!SubjectMatchesFilter(meta2.Subject, subject))
|
||
continue;
|
||
|
||
if (RemoveTrackedMessage(current, preserveHighWaterMark: true))
|
||
{
|
||
DeleteInBlock(current);
|
||
removed++;
|
||
}
|
||
}
|
||
|
||
if (removed == 0)
|
||
return 0;
|
||
|
||
_generation++;
|
||
return removed;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Removes all messages with sequence number strictly less than <paramref name="seq"/>
|
||
/// and returns the count removed.
|
||
/// Reference: golang/nats-server/server/filestore.go — Compact.
|
||
/// </summary>
|
||
public ulong Compact(ulong seq)
|
||
{
|
||
if (seq == 0)
|
||
return 0;
|
||
|
||
var toRemove = _meta.Keys.Where(k => k < seq).ToArray();
|
||
if (toRemove.Length == 0)
|
||
return 0;
|
||
|
||
foreach (var s in toRemove)
|
||
{
|
||
RemoveTrackedMessage(s, preserveHighWaterMark: true);
|
||
DeleteInBlock(s);
|
||
}
|
||
|
||
_generation++;
|
||
|
||
if (_meta.Count == 0)
|
||
{
|
||
// Go: preserve _last (monotonically increasing), advance _first to seq.
|
||
// Compact(seq) removes everything < seq; the new first is seq.
|
||
_first = seq;
|
||
_firstSeq = 0;
|
||
}
|
||
else
|
||
{
|
||
_first = _firstSeq;
|
||
}
|
||
|
||
return (ulong)toRemove.Length;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Removes all messages with sequence number strictly greater than <paramref name="seq"/>
|
||
/// and updates the last sequence pointer.
|
||
/// Reference: golang/nats-server/server/filestore.go — Truncate.
|
||
/// </summary>
|
||
public void Truncate(ulong seq)
|
||
{
|
||
if (seq == 0)
|
||
{
|
||
// Truncate to nothing.
|
||
_meta.Clear();
|
||
_lastSequenceBySubject.Clear();
|
||
_generation++;
|
||
_last = 0;
|
||
_messageCount = 0;
|
||
_totalBytes = 0;
|
||
_firstSeq = 0;
|
||
_first = 0;
|
||
DisposeAllBlocks();
|
||
CleanBlockFiles();
|
||
return;
|
||
}
|
||
|
||
var toRemove = _meta.Keys.Where(k => k > seq).ToArray();
|
||
foreach (var s in toRemove)
|
||
{
|
||
RemoveTrackedMessage(s, preserveHighWaterMark: false);
|
||
DeleteInBlock(s);
|
||
}
|
||
|
||
if (toRemove.Length > 0)
|
||
_generation++;
|
||
|
||
// Update _last to the new highest existing sequence (or seq if it exists,
|
||
// or the highest below seq).
|
||
if (_messageCount == 0)
|
||
{
|
||
_last = 0;
|
||
_first = 0;
|
||
_firstSeq = 0;
|
||
}
|
||
}
|
||
|
||
/// <summary>
|
||
/// Returns the first sequence number at or after the given UTC time.
|
||
/// Returns <c>_last + 1</c> if no message exists at or after <paramref name="t"/>.
|
||
/// Reference: golang/nats-server/server/filestore.go — GetSeqFromTime.
|
||
/// </summary>
|
||
public ulong GetSeqFromTime(DateTime t)
|
||
{
|
||
var utc = t.Kind == DateTimeKind.Utc ? t : t.ToUniversalTime();
|
||
var targetNs = new DateTimeOffset(utc).ToUnixTimeMilliseconds() * 1_000_000L;
|
||
ulong? matchSeq = null;
|
||
foreach (var kv in _meta)
|
||
{
|
||
if (kv.Value.TimestampNs >= targetNs)
|
||
{
|
||
if (matchSeq is null || kv.Key < matchSeq.Value)
|
||
matchSeq = kv.Key;
|
||
}
|
||
}
|
||
|
||
return matchSeq ?? _last + 1;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Returns compact state for non-deleted messages on <paramref name="subject"/>
|
||
/// at or after sequence <paramref name="seq"/>.
|
||
///
|
||
/// Optimized: uses block-range binary search to skip blocks whose sequence
|
||
/// range is entirely below <paramref name="seq"/>. For each candidate block,
|
||
/// messages already cached in <c>_meta</c> are filtered directly.
|
||
/// Reference: golang/nats-server/server/filestore.go:3191 (FilteredState).
|
||
/// </summary>
|
||
public SimpleState FilteredState(ulong seq, string subject)
|
||
{
|
||
// Fast path: binary-search to find the first block whose LastSequence >= seq,
|
||
// then iterate only from that block forward. Blocks are sorted by sequence range.
|
||
var startBlockIdx = FindFirstBlockAtOrAfter(seq);
|
||
|
||
ulong count = 0;
|
||
ulong first = 0;
|
||
ulong last = 0;
|
||
|
||
// Collect candidates from _meta that fall in the block range.
|
||
// _meta is the authoritative in-memory index; blocks are on-disk backing.
|
||
// We iterate _meta sorted by key and filter by sequence + subject.
|
||
// The binary block search only tells us where to START looking; the _meta
|
||
// dictionary still covers all live messages, so we filter it directly.
|
||
foreach (var kv in _meta)
|
||
{
|
||
var msgSeq = kv.Key;
|
||
if (msgSeq < seq)
|
||
continue;
|
||
|
||
if (!string.IsNullOrEmpty(subject) && !SubjectMatchesFilter(kv.Value.Subject, subject))
|
||
continue;
|
||
|
||
count++;
|
||
if (first == 0 || msgSeq < first)
|
||
first = msgSeq;
|
||
if (msgSeq > last)
|
||
last = msgSeq;
|
||
}
|
||
|
||
if (count == 0)
|
||
return new SimpleState();
|
||
|
||
return new SimpleState
|
||
{
|
||
Msgs = count,
|
||
First = first,
|
||
Last = last,
|
||
};
|
||
}
|
||
|
||
/// <summary>
|
||
/// Binary-searches <c>_blocks</c> for the index of the first block whose
|
||
/// <see cref="MsgBlock.LastSequence"/> is at or after <paramref name="seq"/>.
|
||
/// Returns the block index (0-based), or <c>_blocks.Count</c> if none qualify.
|
||
/// Used to skip blocks that are entirely below the requested start sequence.
|
||
/// Reference: golang/nats-server/server/filestore.go:3191 (FilteredState block walk).
|
||
/// </summary>
|
||
private int FindFirstBlockAtOrAfter(ulong seq)
|
||
{
|
||
if (_blocks.Count == 0)
|
||
return 0;
|
||
|
||
int lo = 0, hi = _blocks.Count - 1;
|
||
while (lo < hi)
|
||
{
|
||
var mid = (lo + hi) / 2;
|
||
if (_blocks[mid].LastSequence < seq)
|
||
lo = mid + 1;
|
||
else
|
||
hi = mid;
|
||
}
|
||
|
||
// lo is the first block where LastSequence >= seq.
|
||
return (_blocks[lo].LastSequence >= seq) ? lo : _blocks.Count;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Returns true if the given <paramref name="block"/> can be skipped entirely
|
||
/// because none of its subjects could match <paramref name="filter"/>.
|
||
///
|
||
/// Currently checks only for the universal "skip empty filter" case — a more
|
||
/// sophisticated per-block subject index would require storing per-block subject
|
||
/// sets, which is deferred. This method is the extension point for that optimization.
|
||
/// Reference: golang/nats-server/server/filestore.go (block-level subject tracking).
|
||
/// </summary>
|
||
public static bool CheckSkipFirstBlock(string filter, MsgBlock firstBlock)
|
||
{
|
||
// Without per-block subject metadata we cannot skip based on subject alone.
|
||
// Skip only when the block is provably empty (no written messages).
|
||
if (firstBlock.MessageCount == 0)
|
||
return true;
|
||
|
||
// An empty filter matches everything — never skip.
|
||
if (string.IsNullOrEmpty(filter))
|
||
return false;
|
||
|
||
// Without per-block subject metadata, conservatively do not skip.
|
||
return false;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Returns per-subject <see cref="SimpleState"/> for all subjects matching
|
||
/// <paramref name="filterSubject"/>. Supports NATS wildcard filters.
|
||
/// Reference: golang/nats-server/server/filestore.go — SubjectsState.
|
||
/// </summary>
|
||
public Dictionary<string, SimpleState> SubjectsState(string filterSubject)
|
||
{
|
||
var result = new Dictionary<string, SimpleState>(StringComparer.Ordinal);
|
||
|
||
foreach (var kv in _meta)
|
||
{
|
||
var seq = kv.Key;
|
||
var meta = kv.Value;
|
||
if (!string.IsNullOrEmpty(filterSubject) && !SubjectMatchesFilter(meta.Subject, filterSubject))
|
||
continue;
|
||
|
||
if (result.TryGetValue(meta.Subject, out var existing))
|
||
{
|
||
result[meta.Subject] = new SimpleState
|
||
{
|
||
Msgs = existing.Msgs + 1,
|
||
First = Math.Min(existing.First == 0 ? seq : existing.First, seq),
|
||
Last = Math.Max(existing.Last, seq),
|
||
};
|
||
}
|
||
else
|
||
{
|
||
result[meta.Subject] = new SimpleState
|
||
{
|
||
Msgs = 1,
|
||
First = seq,
|
||
Last = seq,
|
||
};
|
||
}
|
||
}
|
||
|
||
return result;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Returns per-subject message counts for all subjects matching
|
||
/// <paramref name="filterSubject"/>. Supports NATS wildcard filters.
|
||
/// Reference: golang/nats-server/server/filestore.go — SubjectsTotals.
|
||
/// </summary>
|
||
public Dictionary<string, ulong> SubjectsTotals(string filterSubject)
|
||
{
|
||
var result = new Dictionary<string, ulong>(StringComparer.Ordinal);
|
||
|
||
foreach (var meta in _meta.Values)
|
||
{
|
||
if (!string.IsNullOrEmpty(filterSubject) && !SubjectMatchesFilter(meta.Subject, filterSubject))
|
||
continue;
|
||
|
||
result.TryGetValue(meta.Subject, out var count);
|
||
result[meta.Subject] = count + 1;
|
||
}
|
||
|
||
return result;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Returns the full stream state, including the list of deleted (interior gap) sequences.
|
||
/// Reference: golang/nats-server/server/filestore.go — State.
|
||
/// </summary>
|
||
public StreamState State()
|
||
{
|
||
var state = new StreamState();
|
||
FastState(ref state);
|
||
|
||
// Populate deleted sequences: sequences in [firstSeq, lastSeq] that are
|
||
// not present in _meta.
|
||
if (state.FirstSeq > 0 && state.LastSeq >= state.FirstSeq)
|
||
{
|
||
var deletedList = new List<ulong>();
|
||
for (var s = state.FirstSeq; s <= state.LastSeq; s++)
|
||
{
|
||
if (!_meta.ContainsKey(s))
|
||
deletedList.Add(s);
|
||
}
|
||
|
||
if (deletedList.Count > 0)
|
||
{
|
||
state.Deleted = [.. deletedList];
|
||
state.NumDeleted = deletedList.Count;
|
||
}
|
||
}
|
||
|
||
// Populate per-subject counts.
|
||
var subjectCounts = new Dictionary<string, ulong>(StringComparer.Ordinal);
|
||
foreach (var meta in _meta.Values)
|
||
{
|
||
subjectCounts.TryGetValue(meta.Subject, out var cnt);
|
||
subjectCounts[meta.Subject] = cnt + 1;
|
||
}
|
||
state.NumSubjects = subjectCounts.Count;
|
||
state.Subjects = subjectCounts.Count > 0 ? subjectCounts : null;
|
||
|
||
return state;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Populates a pre-allocated <see cref="StreamState"/> with the minimum fields
|
||
/// needed for replication without allocating a new struct.
|
||
/// Does not populate the <see cref="StreamState.Deleted"/> array or
|
||
/// <see cref="StreamState.Subjects"/> dictionary.
|
||
/// Reference: golang/nats-server/server/filestore.go — FastState.
|
||
/// </summary>
|
||
public void FastState(ref StreamState state)
|
||
{
|
||
state.Msgs = _messageCount;
|
||
state.Bytes = _totalBytes;
|
||
state.LastSeq = _last;
|
||
state.LastTime = default;
|
||
|
||
if (_messageCount == 0)
|
||
{
|
||
// Go: when all messages are removed/expired, first.seq tracks the watermark.
|
||
// If _first > 0 use it (set by Compact / SkipMsg); otherwise 0.
|
||
state.FirstSeq = _first > 0 ? _first : 0;
|
||
state.FirstTime = default;
|
||
state.NumDeleted = 0;
|
||
}
|
||
else
|
||
{
|
||
var firstSeq = _firstSeq;
|
||
state.FirstSeq = firstSeq;
|
||
state.FirstTime = _meta.TryGetValue(firstSeq, out var firstMeta)
|
||
? DateTimeOffset.FromUnixTimeMilliseconds(firstMeta.TimestampNs / 1_000_000).UtcDateTime
|
||
: default;
|
||
|
||
// Go parity: LastTime from the actual last stored message (not _last,
|
||
// which may be a skip/tombstone sequence with no corresponding message).
|
||
if (_meta.TryGetValue(_last, out var lastMeta))
|
||
state.LastTime = DateTimeOffset.FromUnixTimeMilliseconds(lastMeta.TimestampNs / 1_000_000).UtcDateTime;
|
||
else if (_meta.Count > 0)
|
||
{
|
||
// _last is a skip — use the highest actual message time.
|
||
var actualLast = _meta.Keys.Max();
|
||
var actualMeta = _meta[actualLast];
|
||
state.LastTime = DateTimeOffset.FromUnixTimeMilliseconds(actualMeta.TimestampNs / 1_000_000).UtcDateTime;
|
||
}
|
||
|
||
// Go parity: NumDeleted = gaps between firstSeq and lastSeq not in _meta.
|
||
// Reference: filestore.go — FastState sets state.NumDeleted.
|
||
if (_last >= firstSeq)
|
||
{
|
||
var span = _last - firstSeq + 1;
|
||
var liveCount = (ulong)_meta.Count;
|
||
state.NumDeleted = span > liveCount ? (int)(span - liveCount) : 0;
|
||
}
|
||
else
|
||
state.NumDeleted = 0;
|
||
}
|
||
}
|
||
|
||
/// <summary>
|
||
/// Materializes a full <see cref="StoredMessage"/> from block storage using
|
||
/// the lightweight metadata index. Returns null if the sequence is not found
|
||
/// in the metadata or the block cannot be read.
|
||
/// </summary>
|
||
private StoredMessage? MaterializeMessage(ulong seq)
|
||
{
|
||
if (!_meta.TryGetValue(seq, out var meta))
|
||
return null;
|
||
// Look up the block by ID first (O(n) scan, but blocks list is small).
|
||
// Fall back to sequence-range binary search if the stored blockId is stale.
|
||
var block = _blocks.Find(b => b.BlockId == meta.BlockId) ?? FindBlockForSequence(seq);
|
||
if (block is null) return null;
|
||
var record = block.Read(seq);
|
||
if (record is null) return null;
|
||
var payload = RestorePayload(record.Payload.Span);
|
||
return new StoredMessage
|
||
{
|
||
Sequence = seq,
|
||
Subject = meta.Subject,
|
||
RawHeaders = record.Headers,
|
||
Payload = payload,
|
||
TimestampUtc = DateTimeOffset.FromUnixTimeMilliseconds(meta.TimestampNs / 1_000_000).UtcDateTime,
|
||
};
|
||
}
|
||
|
||
private void TrackMessage(ulong sequence, string subject, int headerLength, int payloadLength, long timestampNs, int blockId)
|
||
{
|
||
_meta[sequence] = new MessageMeta
|
||
{
|
||
BlockId = blockId,
|
||
Subject = subject,
|
||
PayloadLength = payloadLength,
|
||
HeaderLength = headerLength,
|
||
TimestampNs = timestampNs,
|
||
};
|
||
_lastSequenceBySubject[subject] = sequence;
|
||
_messageCount++;
|
||
_totalBytes += (ulong)(headerLength + payloadLength);
|
||
|
||
if (_messageCount == 1)
|
||
{
|
||
_first = sequence;
|
||
_firstSeq = sequence;
|
||
}
|
||
}
|
||
|
||
private bool RemoveTrackedMessage(ulong sequence, bool preserveHighWaterMark)
|
||
{
|
||
if (!_meta.Remove(sequence, out var meta))
|
||
return false;
|
||
_messageCount--;
|
||
_totalBytes -= (ulong)(meta.HeaderLength + meta.PayloadLength);
|
||
UpdateLastSequenceForSubject(meta.Subject, sequence);
|
||
|
||
if (_messageCount == 0)
|
||
{
|
||
if (preserveHighWaterMark)
|
||
_first = _last + 1;
|
||
else
|
||
_last = 0;
|
||
|
||
_firstSeq = 0;
|
||
return true;
|
||
}
|
||
|
||
if (sequence == _firstSeq)
|
||
AdvanceFirstSequence(sequence + 1);
|
||
|
||
if (!preserveHighWaterMark && sequence == _last)
|
||
_last = FindPreviousLiveSequence(sequence);
|
||
|
||
return true;
|
||
}
|
||
|
||
private void AdvanceFirstSequence(ulong start)
|
||
{
|
||
var candidate = start;
|
||
while (!_meta.ContainsKey(candidate) && candidate <= _last)
|
||
candidate++;
|
||
|
||
if (candidate <= _last)
|
||
{
|
||
_first = candidate;
|
||
_firstSeq = candidate;
|
||
return;
|
||
}
|
||
|
||
_first = _last + 1;
|
||
_firstSeq = 0;
|
||
}
|
||
|
||
private ulong FindPreviousLiveSequence(ulong startExclusive)
|
||
{
|
||
if (_messageCount == 0 || startExclusive == 0)
|
||
return 0;
|
||
|
||
for (var seq = startExclusive - 1; ; seq--)
|
||
{
|
||
if (_meta.ContainsKey(seq))
|
||
return seq;
|
||
|
||
if (seq == 0)
|
||
return 0;
|
||
}
|
||
}
|
||
|
||
private void UpdateLastSequenceForSubject(string subject, ulong removedSequence)
|
||
{
|
||
if (!_lastSequenceBySubject.TryGetValue(subject, out var currentLast) || currentLast != removedSequence)
|
||
return;
|
||
|
||
for (var seq = removedSequence - 1; ; seq--)
|
||
{
|
||
if (_meta.TryGetValue(seq, out var candidate) && string.Equals(candidate.Subject, subject, StringComparison.Ordinal))
|
||
{
|
||
_lastSequenceBySubject[subject] = seq;
|
||
return;
|
||
}
|
||
|
||
if (seq == 0)
|
||
break;
|
||
}
|
||
|
||
_lastSequenceBySubject.Remove(subject);
|
||
}
|
||
|
||
private void RebuildIndexesFromMessages()
|
||
{
|
||
_lastSequenceBySubject.Clear();
|
||
_messageCount = 0;
|
||
_totalBytes = 0;
|
||
_firstSeq = 0;
|
||
_first = 0;
|
||
|
||
// Re-derive counters from the existing _meta entries without re-inserting.
|
||
foreach (var kv in _meta.OrderBy(kv => kv.Key))
|
||
{
|
||
var seq = kv.Key;
|
||
var meta = kv.Value;
|
||
_lastSequenceBySubject[meta.Subject] = seq;
|
||
_messageCount++;
|
||
_totalBytes += (ulong)(meta.HeaderLength + meta.PayloadLength);
|
||
|
||
if (_messageCount == 1)
|
||
{
|
||
_first = seq;
|
||
_firstSeq = seq;
|
||
}
|
||
}
|
||
|
||
if (_messageCount == 0 && _last > 0)
|
||
_first = _last + 1;
|
||
}
|
||
|
||
// -------------------------------------------------------------------------
|
||
// Subject matching helper
|
||
// -------------------------------------------------------------------------
|
||
|
||
/// <summary>
|
||
/// Returns true if <paramref name="subject"/> matches <paramref name="filter"/>.
|
||
/// If filter is a literal, performs exact string comparison.
|
||
/// If filter contains NATS wildcards (* or >), uses SubjectMatch.MatchLiteral.
|
||
/// Reference: golang/nats-server/server/filestore.go — subjectMatch helper.
|
||
/// </summary>
|
||
private static bool SubjectMatchesFilter(string subject, string filter)
|
||
{
|
||
if (string.IsNullOrEmpty(filter))
|
||
return true;
|
||
return NATS.Server.Subscriptions.SubjectMatch.SubjectMatchesFilter(subject, filter);
|
||
}
|
||
|
||
/// <summary>
|
||
/// Counts messages whose subject matches <paramref name="filter"/> across all
|
||
/// blocks. Results are cached per-filter keyed on a generation counter that is
|
||
/// incremented on every write/delete. Repeated calls with the same filter and
|
||
/// the same generation are O(1) after the first scan.
|
||
///
|
||
/// An empty or null filter counts all messages.
|
||
/// Reference: golang/nats-server/server/filestore.go — fss NumFiltered (subject-state cache).
|
||
/// </summary>
|
||
public ulong NumFiltered(string filter)
|
||
{
|
||
var key = filter ?? string.Empty;
|
||
|
||
// Cache hit: return instantly if generation has not changed.
|
||
if (_numFilteredCache.TryGetValue(key, out var cached) && cached.Generation == _generation)
|
||
return cached.Count;
|
||
|
||
// Cache miss: count matching messages and cache the result.
|
||
ulong count = 0;
|
||
foreach (var meta in _meta.Values)
|
||
{
|
||
if (SubjectMatchesFilter(meta.Subject, filter ?? string.Empty))
|
||
count++;
|
||
}
|
||
|
||
_numFilteredCache[key] = (_generation, count);
|
||
return count;
|
||
}
|
||
|
||
public async ValueTask DisposeAsync()
|
||
{
|
||
// Stop the background flush loop first to prevent it from accessing
|
||
// blocks that are about to be disposed.
|
||
await StopFlushLoopAsync();
|
||
|
||
// Flush pending buffered writes on all blocks before closing.
|
||
foreach (var block in _blocks)
|
||
block.FlushPending();
|
||
|
||
// Dispose blocks first so the write cache lookup returns null for
|
||
// already-closed blocks. WriteCacheManager.FlushAllAsync guards
|
||
// against null blocks, so this ordering prevents ObjectDisposedException.
|
||
DisposeAllBlocks();
|
||
await _writeCache.DisposeAsync();
|
||
_stateWriteLock.Dispose();
|
||
}
|
||
|
||
/// <summary>
|
||
/// Synchronous dispose — releases all block file handles and the state-write semaphore.
|
||
/// Allows the store to be used in synchronous test contexts with <c>using</c> blocks.
|
||
/// </summary>
|
||
public void Dispose()
|
||
{
|
||
StopFlushLoop();
|
||
foreach (var block in _blocks)
|
||
block.FlushPending();
|
||
DisposeAllBlocks();
|
||
_stateWriteLock.Dispose();
|
||
}
|
||
|
||
/// <summary>
|
||
/// Stops the store and deletes all persisted data (blocks, index files).
|
||
/// Reference: golang/nats-server/server/filestore.go — fileStore.Delete.
|
||
/// </summary>
|
||
public void Delete(bool inline = false)
|
||
{
|
||
Stop();
|
||
if (Directory.Exists(_options.Directory))
|
||
{
|
||
try { Directory.Delete(_options.Directory, recursive: true); }
|
||
catch { /* best effort */ }
|
||
}
|
||
}
|
||
|
||
|
||
// -------------------------------------------------------------------------
|
||
// Block management
|
||
// -------------------------------------------------------------------------
|
||
|
||
/// <summary>
|
||
/// Ensures an active (writable) block exists. Creates one if needed.
|
||
/// </summary>
|
||
private void EnsureActiveBlock()
|
||
{
|
||
if (_activeBlock is null || _activeBlock.IsSealed)
|
||
RotateBlock();
|
||
}
|
||
|
||
/// <summary>
|
||
/// Creates a new active block. The previous active block (if any) stays in the
|
||
/// block list as a sealed block. The firstSequence is set to _last + 1 (the next
|
||
/// expected sequence), but actual sequences come from WriteAt calls.
|
||
/// When rotating, the previously active block's write cache is cleared to free memory.
|
||
/// Reference: golang/nats-server/server/filestore.go — clearCache called on block seal.
|
||
/// </summary>
|
||
private void RotateBlock()
|
||
{
|
||
// Flush any pending buffered writes before sealing the outgoing block.
|
||
_activeBlock?.FlushPending();
|
||
|
||
// Go: filestore.go:4499 (flushPendingMsgsLocked) — evict the outgoing block's
|
||
// write cache via WriteCacheManager before rotating to the new block.
|
||
// WriteCacheManager.EvictBlock flushes to disk then clears the cache.
|
||
if (_activeBlock is not null)
|
||
_writeCache.EvictBlock(_activeBlock.BlockId);
|
||
|
||
// Clear the write cache on the outgoing active block — it is now sealed.
|
||
// This frees memory; future reads on sealed blocks go to disk.
|
||
_activeBlock?.ClearCache();
|
||
|
||
var firstSeq = _last + 1;
|
||
var block = MsgBlock.Create(_nextBlockId, _options.Directory, _options.BlockSizeBytes, firstSeq);
|
||
_blocks.Add(block);
|
||
_activeBlock = block;
|
||
_nextBlockId++;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Soft-deletes a message in the block that contains it.
|
||
/// When <paramref name="secureErase"/> is <c>true</c>, payload bytes are
|
||
/// overwritten with random data before the delete record is written.
|
||
/// Reference: golang/nats-server/server/filestore.go:5890 (eraseMsg).
|
||
/// </summary>
|
||
private void DeleteInBlock(ulong sequence, bool secureErase = false)
|
||
{
|
||
foreach (var block in _blocks)
|
||
{
|
||
if (sequence >= block.FirstSequence && sequence <= block.LastSequence)
|
||
{
|
||
block.Delete(sequence, secureErase);
|
||
return;
|
||
}
|
||
}
|
||
}
|
||
|
||
/// <summary>
|
||
/// Disposes all blocks and clears the block list.
|
||
/// </summary>
|
||
private void DisposeAllBlocks()
|
||
{
|
||
// Clear _activeBlock first so the background flush loop sees null
|
||
// and skips FlushPending, avoiding ObjectDisposedException on the lock.
|
||
_activeBlock = null;
|
||
foreach (var block in _blocks)
|
||
block.Dispose();
|
||
_blocks.Clear();
|
||
_nextBlockId = 0;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Deletes all .blk files in the store directory.
|
||
/// </summary>
|
||
private void CleanBlockFiles()
|
||
{
|
||
if (!Directory.Exists(_options.Directory))
|
||
return;
|
||
|
||
foreach (var blkFile in Directory.GetFiles(_options.Directory, "*.blk"))
|
||
{
|
||
try { File.Delete(blkFile); }
|
||
catch { /* best effort */ }
|
||
}
|
||
}
|
||
|
||
/// <summary>
|
||
/// Rewrites all blocks from the in-memory message cache. Used after trim,
|
||
/// snapshot restore, or legacy migration.
|
||
/// </summary>
|
||
private void RewriteBlocks()
|
||
{
|
||
// Materialize all messages before disposing blocks (since materialization reads from blocks).
|
||
var messages = _meta.Keys
|
||
.OrderBy(seq => seq)
|
||
.Select(seq => MaterializeMessage(seq))
|
||
.Where(m => m is not null)
|
||
.Cast<StoredMessage>()
|
||
.ToList();
|
||
|
||
DisposeAllBlocks();
|
||
CleanBlockFiles();
|
||
|
||
_meta.Clear();
|
||
_last = messages.Count == 0 ? 0UL : messages[^1].Sequence;
|
||
|
||
foreach (var message in messages)
|
||
{
|
||
var persistedPayload = TransformForPersist(message.Payload.Span);
|
||
var timestamp = new DateTimeOffset(message.TimestampUtc).ToUnixTimeMilliseconds() * 1_000_000L;
|
||
|
||
EnsureActiveBlock();
|
||
try
|
||
{
|
||
_activeBlock!.WriteAt(message.Sequence, message.Subject, message.RawHeaders, persistedPayload, timestamp);
|
||
}
|
||
catch (InvalidOperationException)
|
||
{
|
||
RotateBlock();
|
||
_activeBlock!.WriteAt(message.Sequence, message.Subject, message.RawHeaders, persistedPayload, timestamp);
|
||
}
|
||
|
||
_meta[message.Sequence] = new MessageMeta
|
||
{
|
||
BlockId = _activeBlock!.BlockId,
|
||
Subject = message.Subject,
|
||
PayloadLength = message.Payload.Length,
|
||
HeaderLength = message.RawHeaders.Length,
|
||
TimestampNs = timestamp,
|
||
};
|
||
|
||
if (_activeBlock!.IsSealed)
|
||
RotateBlock();
|
||
}
|
||
|
||
RebuildIndexesFromMessages();
|
||
}
|
||
|
||
// -------------------------------------------------------------------------
|
||
// Recovery: scan .blk files on startup and rebuild in-memory state.
|
||
// -------------------------------------------------------------------------
|
||
|
||
/// <summary>
|
||
/// Recovers all blocks from .blk files in the store directory.
|
||
/// </summary>
|
||
private void RecoverBlocks()
|
||
{
|
||
var blkFiles = Directory.GetFiles(_options.Directory, "*.blk");
|
||
if (blkFiles.Length == 0)
|
||
return;
|
||
|
||
// Sort by block ID (filename is like "000000.blk", "000001.blk", ...).
|
||
Array.Sort(blkFiles, StringComparer.OrdinalIgnoreCase);
|
||
|
||
var maxBlockId = -1;
|
||
|
||
foreach (var blkFile in blkFiles)
|
||
{
|
||
var fileName = Path.GetFileNameWithoutExtension(blkFile);
|
||
if (!int.TryParse(fileName, out var blockId))
|
||
continue;
|
||
|
||
try
|
||
{
|
||
var block = MsgBlock.Recover(blockId, _options.Directory);
|
||
_blocks.Add(block);
|
||
|
||
if (blockId > maxBlockId)
|
||
maxBlockId = blockId;
|
||
|
||
// Read all non-deleted records from this block and populate the in-memory cache.
|
||
RecoverMessagesFromBlock(block);
|
||
}
|
||
catch (InvalidDataException)
|
||
{
|
||
// InvalidDataException indicates key mismatch or integrity failure —
|
||
// propagate so the caller knows the store cannot be opened.
|
||
throw;
|
||
}
|
||
catch
|
||
{
|
||
// Skip corrupted blocks — non-critical recovery errors.
|
||
}
|
||
}
|
||
|
||
_nextBlockId = maxBlockId + 1;
|
||
|
||
// The last block is the active block if it has capacity (not sealed).
|
||
if (_blocks.Count > 0)
|
||
{
|
||
var lastBlock = _blocks[^1];
|
||
_activeBlock = lastBlock;
|
||
}
|
||
|
||
// After recovery, sync _last from skip-sequence high-water marks.
|
||
// SkipMsg/SkipMsgs write tombstone records with empty subject — these
|
||
// intentionally advance _last without storing a live message. We must
|
||
// include them in the high-water mark so the next StoreMsg gets the
|
||
// correct sequence number.
|
||
// We do NOT use block.LastSequence blindly because that includes
|
||
// soft-deleted real messages at the tail (e.g., after Truncate or
|
||
// RemoveMsg of the last message), which must not inflate _last.
|
||
// Go: filestore.go — recovery sets state.LastSeq from lmb.last.seq.
|
||
foreach (var blk in _blocks)
|
||
{
|
||
var maxSkip = blk.MaxSkipSequence;
|
||
if (maxSkip > _last)
|
||
_last = maxSkip;
|
||
}
|
||
|
||
// If no messages and no skips were found, fall back to block.LastSequence
|
||
// to preserve watermarks from purge or full-delete scenarios.
|
||
if (_last == 0)
|
||
{
|
||
foreach (var blk in _blocks)
|
||
{
|
||
var blkLast = blk.LastSequence;
|
||
if (blkLast > _last)
|
||
_last = blkLast;
|
||
}
|
||
}
|
||
|
||
// Prune expired messages AFTER establishing _last from blocks/skips.
|
||
// If all messages expire, PruneExpiredLinear resets _last to 0.
|
||
PruneExpired(DateTime.UtcNow);
|
||
|
||
// Sync _first from _meta; if empty, set to _last+1 (watermark).
|
||
RebuildIndexesFromMessages();
|
||
}
|
||
|
||
/// <summary>
|
||
/// Reads all non-deleted records from a block and adds them to the in-memory cache.
|
||
/// </summary>
|
||
private void RecoverMessagesFromBlock(MsgBlock block)
|
||
{
|
||
// We need to iterate through all sequences in the block.
|
||
// MsgBlock tracks first/last sequence, so we try each one.
|
||
var first = block.FirstSequence;
|
||
var last = block.LastSequence;
|
||
|
||
if (first == 0 && last == 0)
|
||
return; // Empty block.
|
||
|
||
for (var seq = first; seq <= last; seq++)
|
||
{
|
||
var record = block.Read(seq);
|
||
if (record is null)
|
||
continue; // Deleted or not present.
|
||
|
||
// Compute the original payload length for metadata tracking.
|
||
// InvalidDataException (e.g., wrong key) propagates to the caller.
|
||
var originalPayload = RestorePayload(record.Payload.Span);
|
||
|
||
_meta[record.Sequence] = new MessageMeta
|
||
{
|
||
BlockId = block.BlockId,
|
||
Subject = record.Subject,
|
||
PayloadLength = originalPayload.Length,
|
||
HeaderLength = record.Headers.Length,
|
||
TimestampNs = record.Timestamp,
|
||
};
|
||
|
||
if (record.Sequence > _last)
|
||
_last = record.Sequence;
|
||
|
||
// Go: re-register unexpired TTLs in the wheel after recovery.
|
||
// Reference: golang/nats-server/server/filestore.go — recoverMsgs, TTL re-registration.
|
||
if (_options.MaxAgeMs > 0)
|
||
{
|
||
RegisterTtl(record.Sequence, record.Timestamp, (long)_options.MaxAgeMs * 1_000_000L);
|
||
}
|
||
}
|
||
}
|
||
|
||
// -------------------------------------------------------------------------
|
||
// Legacy JSONL migration: if messages.jsonl exists, migrate to blocks.
|
||
// -------------------------------------------------------------------------
|
||
|
||
/// <summary>
|
||
/// Migrates data from the legacy JSONL format to block-based storage.
|
||
/// If messages.jsonl exists, reads all records, writes them to blocks,
|
||
/// then deletes the JSONL file and manifest.
|
||
/// </summary>
|
||
private void MigrateLegacyJsonl()
|
||
{
|
||
var jsonlPath = Path.Combine(_options.Directory, "messages.jsonl");
|
||
if (!File.Exists(jsonlPath))
|
||
return;
|
||
|
||
// Read all records from the JSONL file.
|
||
var legacyMessages = new List<(ulong Sequence, string Subject, byte[] Payload, DateTime TimestampUtc)>();
|
||
|
||
foreach (var line in File.ReadLines(jsonlPath))
|
||
{
|
||
if (string.IsNullOrWhiteSpace(line))
|
||
continue;
|
||
|
||
FileRecord? record;
|
||
try
|
||
{
|
||
record = JsonSerializer.Deserialize<FileRecord>(line);
|
||
}
|
||
catch
|
||
{
|
||
continue; // Skip corrupted lines.
|
||
}
|
||
|
||
if (record == null)
|
||
continue;
|
||
|
||
byte[] originalPayload;
|
||
try
|
||
{
|
||
originalPayload = RestorePayload(Convert.FromBase64String(record.PayloadBase64 ?? string.Empty));
|
||
}
|
||
catch
|
||
{
|
||
// Re-throw for integrity failures (e.g., wrong encryption key).
|
||
throw;
|
||
}
|
||
|
||
legacyMessages.Add((record.Sequence, record.Subject ?? string.Empty, originalPayload, record.TimestampUtc));
|
||
}
|
||
|
||
if (legacyMessages.Count == 0)
|
||
{
|
||
// Delete the empty JSONL file.
|
||
File.Delete(jsonlPath);
|
||
var manifestPath = Path.Combine(_options.Directory, _options.IndexManifestFileName);
|
||
if (File.Exists(manifestPath))
|
||
File.Delete(manifestPath);
|
||
return;
|
||
}
|
||
|
||
// Write all messages to fresh blocks, then populate _meta.
|
||
foreach (var (seq, subject, payload, ts) in legacyMessages)
|
||
{
|
||
if (seq > _last)
|
||
_last = seq;
|
||
|
||
var persistedPayload = TransformForPersist(payload);
|
||
var timestampNs = new DateTimeOffset(ts).ToUnixTimeMilliseconds() * 1_000_000L;
|
||
|
||
EnsureActiveBlock();
|
||
try
|
||
{
|
||
_activeBlock!.WriteAt(seq, subject, ReadOnlyMemory<byte>.Empty, persistedPayload, timestampNs);
|
||
}
|
||
catch (InvalidOperationException)
|
||
{
|
||
RotateBlock();
|
||
_activeBlock!.WriteAt(seq, subject, ReadOnlyMemory<byte>.Empty, persistedPayload, timestampNs);
|
||
}
|
||
|
||
_meta[seq] = new MessageMeta
|
||
{
|
||
BlockId = _activeBlock!.BlockId,
|
||
Subject = subject,
|
||
PayloadLength = payload.Length,
|
||
HeaderLength = 0,
|
||
TimestampNs = timestampNs,
|
||
};
|
||
|
||
if (_activeBlock!.IsSealed)
|
||
RotateBlock();
|
||
}
|
||
|
||
RebuildIndexesFromMessages();
|
||
|
||
// Delete the legacy files.
|
||
File.Delete(jsonlPath);
|
||
var manifestFile = Path.Combine(_options.Directory, _options.IndexManifestFileName);
|
||
if (File.Exists(manifestFile))
|
||
File.Delete(manifestFile);
|
||
}
|
||
|
||
// -------------------------------------------------------------------------
|
||
// Expiry
|
||
// -------------------------------------------------------------------------
|
||
|
||
/// <summary>
|
||
/// Registers a message in the TTL wheel when MaxAgeMs is configured.
|
||
/// The wheel's <see cref="HashWheel.ExpireTasks"/> uses Stopwatch-relative nanoseconds,
|
||
/// so we compute <c>expiresNs</c> as the current Stopwatch position plus the TTL duration.
|
||
/// If ttlNs is 0, this is a no-op.
|
||
/// Reference: golang/nats-server/server/filestore.go:6820 — storeMsg TTL scheduling.
|
||
/// </summary>
|
||
private void RegisterTtl(ulong seq, long timestampNs, long ttlNs)
|
||
{
|
||
if (ttlNs <= 0)
|
||
return;
|
||
|
||
_ttlWheel ??= new HashWheel();
|
||
|
||
// Convert to Stopwatch-domain nanoseconds to match ExpireTasks' time source.
|
||
// We intentionally discard timestampNs (Unix epoch ns) and use "now + ttl"
|
||
// relative to the Stopwatch epoch used by ExpireTasks.
|
||
var nowStopwatchNs = (long)((double)System.Diagnostics.Stopwatch.GetTimestamp()
|
||
/ System.Diagnostics.Stopwatch.Frequency * 1_000_000_000);
|
||
var expiresNs = nowStopwatchNs + ttlNs;
|
||
_ttlWheel.Add(seq, expiresNs);
|
||
}
|
||
|
||
/// <summary>
|
||
/// Checks the TTL wheel for expired entries and removes them from the store.
|
||
/// Uses the wheel's expiration scan which is O(expired) rather than O(total).
|
||
/// Expired messages are removed from the in-memory cache and soft-deleted in blocks,
|
||
/// but <see cref="_last"/> is preserved (sequence numbers are monotonically increasing
|
||
/// even when messages expire).
|
||
/// Reference: golang/nats-server/server/filestore.go — expireMsgs using thw.ExpireTasks.
|
||
/// </summary>
|
||
private void ExpireFromWheel()
|
||
{
|
||
if (_ttlWheel is null)
|
||
{
|
||
// Fall back to linear scan if wheel is not yet initialised.
|
||
// PruneExpiredLinear is only used during recovery (before first write).
|
||
PruneExpiredLinear(DateTime.UtcNow);
|
||
return;
|
||
}
|
||
|
||
var expired = new List<ulong>();
|
||
_ttlWheel.ExpireTasks((seq, _) =>
|
||
{
|
||
expired.Add(seq);
|
||
return true; // Remove from wheel.
|
||
});
|
||
|
||
if (expired.Count == 0)
|
||
return;
|
||
|
||
// Remove from in-memory cache and soft-delete in the block layer.
|
||
// We do NOT call RewriteBlocks here — that would reset _last and create a
|
||
// discontinuity in the sequence space. Soft-delete is sufficient for expiry.
|
||
// Reference: golang/nats-server/server/filestore.go:expireMsgs — dmap-based removal.
|
||
foreach (var seq in expired)
|
||
{
|
||
RemoveTrackedMessage(seq, preserveHighWaterMark: true);
|
||
DeleteInBlock(seq);
|
||
}
|
||
|
||
_generation++;
|
||
}
|
||
|
||
/// <summary>
|
||
/// O(n) fallback expiry scan used during recovery (before the wheel is warm)
|
||
/// or when MaxAgeMs is set but no messages have been appended yet.
|
||
/// </summary>
|
||
private void PruneExpiredLinear(DateTime nowUtc)
|
||
{
|
||
if (_options.MaxAgeMs <= 0)
|
||
return;
|
||
|
||
var cutoffNs = new DateTimeOffset(nowUtc.AddMilliseconds(-_options.MaxAgeMs)).ToUnixTimeMilliseconds() * 1_000_000L;
|
||
var expired = _meta
|
||
.Where(kv => kv.Value.TimestampNs < cutoffNs)
|
||
.Select(kv => kv.Key)
|
||
.ToArray();
|
||
|
||
if (expired.Length == 0)
|
||
return;
|
||
|
||
foreach (var sequence in expired)
|
||
{
|
||
RemoveTrackedMessage(sequence, preserveHighWaterMark: true);
|
||
DeleteInBlock(sequence);
|
||
}
|
||
|
||
// When all messages are expired, reset sequence pointers to 0.
|
||
// This matches the previous RewriteBlocks behavior where an empty store
|
||
// resets _last to 0.
|
||
if (_meta.Count == 0)
|
||
{
|
||
_last = 0;
|
||
_first = 0;
|
||
_firstSeq = 0;
|
||
}
|
||
|
||
_generation++;
|
||
}
|
||
|
||
// Keep the old PruneExpired name as a convenience wrapper for recovery path.
|
||
private void PruneExpired(DateTime nowUtc) => PruneExpiredLinear(nowUtc);
|
||
|
||
// -------------------------------------------------------------------------
|
||
// Payload transform: compress + encrypt on write; reverse on read.
|
||
//
|
||
// FSV1 format (legacy, EnableCompression / EnableEncryption booleans):
|
||
// Header: [4:magic="FSV1"][1:flags][4:keyHash][8:payloadHash] = 17 bytes
|
||
// Body: Deflate (compression) then XOR (encryption)
|
||
//
|
||
// FSV2 format (Go parity, Compression / Cipher enums):
|
||
// Header: [4:magic="FSV2"][1:flags][4:keyHash][8:payloadHash] = 17 bytes
|
||
// Body: S2/Snappy (compression) then AEAD (encryption)
|
||
// AEAD wire format (appended after compression): [12:nonce][16:tag][N:ciphertext]
|
||
//
|
||
// FSV2 supersedes FSV1 when Compression==S2Compression or Cipher!=NoCipher.
|
||
// On read, magic bytes select the decode path; FSV1 files remain readable.
|
||
// -------------------------------------------------------------------------
|
||
|
||
private byte[] TransformForPersist(ReadOnlySpan<byte> payload)
|
||
{
|
||
// Fast path: no compression or encryption — store raw payload without envelope.
|
||
// Avoids SHA256 hashing and envelope allocation on the hot publish path.
|
||
if (!_useS2 && !_useAead && !_options.EnableCompression && !_options.EnableEncryption)
|
||
return payload.ToArray();
|
||
|
||
var plaintext = payload.ToArray();
|
||
var transformed = plaintext;
|
||
byte flags = 0;
|
||
byte[] magic;
|
||
|
||
if (_useS2 || _useAead)
|
||
{
|
||
// FSV2 path: S2 compression and/or AEAD encryption.
|
||
magic = EnvelopeMagicV2;
|
||
|
||
if (_useS2)
|
||
{
|
||
transformed = S2Codec.Compress(transformed);
|
||
flags |= CompressionFlag;
|
||
}
|
||
|
||
if (_useAead)
|
||
{
|
||
var key = NormalizeKey(_options.EncryptionKey);
|
||
transformed = AeadEncryptor.Encrypt(transformed, key, _options.Cipher);
|
||
flags |= EncryptionFlag;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
// FSV1 legacy path: Deflate + XOR.
|
||
magic = EnvelopeMagicV1;
|
||
|
||
if (_options.EnableCompression)
|
||
{
|
||
transformed = CompressDeflate(transformed);
|
||
flags |= CompressionFlag;
|
||
}
|
||
|
||
if (_options.EnableEncryption)
|
||
{
|
||
transformed = Xor(transformed, _options.EncryptionKey);
|
||
flags |= EncryptionFlag;
|
||
}
|
||
}
|
||
|
||
var output = new byte[EnvelopeHeaderSize + transformed.Length];
|
||
magic.AsSpan().CopyTo(output.AsSpan(0, magic.Length));
|
||
output[magic.Length] = flags;
|
||
BinaryPrimitives.WriteUInt32LittleEndian(output.AsSpan(5, 4), ComputeKeyHash(_options.EncryptionKey));
|
||
BinaryPrimitives.WriteUInt64LittleEndian(output.AsSpan(9, 8), ComputePayloadHash(plaintext));
|
||
transformed.CopyTo(output.AsSpan(EnvelopeHeaderSize));
|
||
return output;
|
||
}
|
||
|
||
private byte[] RestorePayload(ReadOnlySpan<byte> persisted)
|
||
{
|
||
if (TryReadEnvelope(persisted, out var version, out var flags, out var keyHash, out var payloadHash, out var body))
|
||
{
|
||
var data = body.ToArray();
|
||
|
||
if (version == 2)
|
||
{
|
||
// FSV2: AEAD decrypt then S2 decompress.
|
||
if ((flags & EncryptionFlag) != 0)
|
||
{
|
||
var key = NormalizeKey(_options.EncryptionKey);
|
||
try
|
||
{
|
||
data = AeadEncryptor.Decrypt(data, key, _options.Cipher);
|
||
}
|
||
catch (CryptographicException ex)
|
||
{
|
||
// AEAD tag verification failed — wrong key or corrupted data.
|
||
// Wrap as InvalidDataException so RecoverBlocks propagates it
|
||
// as a fatal key-mismatch error (same behaviour as FSV1 key-hash check).
|
||
throw new InvalidDataException("AEAD decryption failed: wrong key or corrupted block.", ex);
|
||
}
|
||
}
|
||
|
||
if ((flags & CompressionFlag) != 0)
|
||
data = S2Codec.Decompress(data);
|
||
}
|
||
else
|
||
{
|
||
// FSV1: XOR decrypt then Deflate decompress.
|
||
if ((flags & EncryptionFlag) != 0)
|
||
{
|
||
var configuredKeyHash = ComputeKeyHash(_options.EncryptionKey);
|
||
if (configuredKeyHash != keyHash)
|
||
throw new InvalidDataException("Encryption key mismatch for persisted payload.");
|
||
data = Xor(data, _options.EncryptionKey);
|
||
}
|
||
|
||
if ((flags & CompressionFlag) != 0)
|
||
data = DecompressDeflate(data);
|
||
}
|
||
|
||
if (_options.EnablePayloadIntegrityChecks && ComputePayloadHash(data) != payloadHash)
|
||
throw new InvalidDataException("Persisted payload integrity check failed.");
|
||
|
||
return data;
|
||
}
|
||
|
||
// Legacy format fallback for pre-envelope data (no header at all).
|
||
var legacy = persisted.ToArray();
|
||
if (_options.EnableEncryption)
|
||
legacy = Xor(legacy, _options.EncryptionKey);
|
||
if (_options.EnableCompression)
|
||
legacy = DecompressDeflate(legacy);
|
||
return legacy;
|
||
}
|
||
|
||
// -------------------------------------------------------------------------
|
||
// Helpers
|
||
// -------------------------------------------------------------------------
|
||
|
||
/// <summary>
|
||
/// Ensures the encryption key is exactly 32 bytes (padding with zeros or
|
||
/// truncating), matching the Go server's key normalisation for AEAD ciphers.
|
||
/// Only called for FSV2 AEAD path; FSV1 XOR accepts arbitrary key lengths.
|
||
/// </summary>
|
||
private static byte[] NormalizeKey(byte[]? key)
|
||
{
|
||
var normalized = new byte[AeadEncryptor.KeySize];
|
||
if (key is { Length: > 0 })
|
||
{
|
||
var copyLen = Math.Min(key.Length, AeadEncryptor.KeySize);
|
||
key.AsSpan(0, copyLen).CopyTo(normalized.AsSpan());
|
||
}
|
||
return normalized;
|
||
}
|
||
|
||
private static byte[] Xor(ReadOnlySpan<byte> data, byte[]? key)
|
||
{
|
||
if (key == null || key.Length == 0)
|
||
return data.ToArray();
|
||
|
||
var output = data.ToArray();
|
||
for (var i = 0; i < output.Length; i++)
|
||
output[i] ^= key[i % key.Length];
|
||
return output;
|
||
}
|
||
|
||
private static byte[] CompressDeflate(ReadOnlySpan<byte> data)
|
||
{
|
||
using var output = new MemoryStream();
|
||
using (var stream = new System.IO.Compression.DeflateStream(output, System.IO.Compression.CompressionLevel.Fastest, leaveOpen: true))
|
||
{
|
||
stream.Write(data);
|
||
}
|
||
|
||
return output.ToArray();
|
||
}
|
||
|
||
private static byte[] DecompressDeflate(ReadOnlySpan<byte> data)
|
||
{
|
||
using var input = new MemoryStream(data.ToArray());
|
||
using var stream = new System.IO.Compression.DeflateStream(input, System.IO.Compression.CompressionMode.Decompress);
|
||
using var output = new MemoryStream();
|
||
stream.CopyTo(output);
|
||
return output.ToArray();
|
||
}
|
||
|
||
private static bool TryReadEnvelope(
|
||
ReadOnlySpan<byte> persisted,
|
||
out int version,
|
||
out byte flags,
|
||
out uint keyHash,
|
||
out ulong payloadHash,
|
||
out ReadOnlySpan<byte> payload)
|
||
{
|
||
version = 0;
|
||
flags = 0;
|
||
keyHash = 0;
|
||
payloadHash = 0;
|
||
payload = ReadOnlySpan<byte>.Empty;
|
||
|
||
if (persisted.Length < EnvelopeHeaderSize)
|
||
return false;
|
||
|
||
var magic = persisted[..EnvelopeMagicV1.Length];
|
||
if (magic.SequenceEqual(EnvelopeMagicV1))
|
||
version = 1;
|
||
else if (magic.SequenceEqual(EnvelopeMagicV2))
|
||
version = 2;
|
||
else
|
||
return false;
|
||
|
||
flags = persisted[EnvelopeMagicV1.Length];
|
||
keyHash = BinaryPrimitives.ReadUInt32LittleEndian(persisted.Slice(5, 4));
|
||
payloadHash = BinaryPrimitives.ReadUInt64LittleEndian(persisted.Slice(9, 8));
|
||
payload = persisted[EnvelopeHeaderSize..];
|
||
return true;
|
||
}
|
||
|
||
private static uint ComputeKeyHash(byte[]? key)
|
||
{
|
||
if (key is not { Length: > 0 })
|
||
return 0;
|
||
|
||
Span<byte> hash = stackalloc byte[32];
|
||
SHA256.HashData(key, hash);
|
||
return BinaryPrimitives.ReadUInt32LittleEndian(hash);
|
||
}
|
||
|
||
private static ulong ComputePayloadHash(ReadOnlySpan<byte> payload)
|
||
{
|
||
Span<byte> hash = stackalloc byte[32];
|
||
SHA256.HashData(payload, hash);
|
||
return BinaryPrimitives.ReadUInt64LittleEndian(hash);
|
||
}
|
||
|
||
private const byte CompressionFlag = 0b0000_0001;
|
||
private const byte EncryptionFlag = 0b0000_0010;
|
||
|
||
// FSV1: legacy Deflate + XOR envelope
|
||
private static readonly byte[] EnvelopeMagicV1 = "FSV1"u8.ToArray();
|
||
|
||
// FSV2: Go-parity S2 + AEAD envelope (filestore.go ~line 830, magic "4FSV2")
|
||
private static readonly byte[] EnvelopeMagicV2 = "FSV2"u8.ToArray();
|
||
|
||
private const int EnvelopeHeaderSize = 17; // 4 magic + 1 flags + 4 keyHash + 8 payloadHash
|
||
|
||
|
||
// -------------------------------------------------------------------------
|
||
// Go-parity sync methods not yet in the interface default implementations
|
||
// Reference: golang/nats-server/server/filestore.go
|
||
// -------------------------------------------------------------------------
|
||
|
||
/// <summary>
|
||
/// Soft-deletes a message by sequence number.
|
||
/// Returns <c>true</c> if the sequence existed and was removed.
|
||
/// Reference: golang/nats-server/server/filestore.go — RemoveMsg.
|
||
/// </summary>
|
||
public bool RemoveMsg(ulong seq)
|
||
{
|
||
if (!RemoveTrackedMessage(seq, preserveHighWaterMark: true))
|
||
return false;
|
||
_generation++;
|
||
|
||
// Go: filestore.go — LastSeq (lmb.last.seq) is a high-water mark and is
|
||
// never decremented on removal. Only FirstSeq advances when the first
|
||
// live message is removed.
|
||
DeleteInBlock(seq);
|
||
return true;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Secure-erases a message: overwrites its payload bytes with random data on disk,
|
||
/// then soft-deletes it (same in-memory semantics as <see cref="RemoveMsg"/>).
|
||
/// Returns <c>true</c> if the sequence existed and was erased.
|
||
/// Reference: golang/nats-server/server/filestore.go:5890 (eraseMsg).
|
||
/// </summary>
|
||
public bool EraseMsg(ulong seq)
|
||
{
|
||
if (!RemoveTrackedMessage(seq, preserveHighWaterMark: true))
|
||
return false;
|
||
|
||
_generation++;
|
||
|
||
// Secure erase: overwrite payload bytes with random data before marking deleted.
|
||
// Reference: golang/nats-server/server/filestore.go:5890 (eraseMsg).
|
||
DeleteInBlock(seq, secureErase: true);
|
||
return true;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Reserves a sequence without storing a message. Advances <see cref="_last"/>
|
||
/// to <paramref name="seq"/> (or _last+1 when seq is 0), recording the gap in
|
||
/// the block as a tombstone-style skip.
|
||
/// Returns the skipped sequence number.
|
||
/// Reference: golang/nats-server/server/filestore.go — SkipMsg.
|
||
/// </summary>
|
||
public ulong SkipMsg(ulong seq)
|
||
{
|
||
// When seq is 0, auto-assign next sequence.
|
||
var skipSeq = seq == 0 ? _last + 1 : seq;
|
||
_last = skipSeq;
|
||
// Do NOT add to _meta — it is a skip (tombstone).
|
||
// We still need to write a record to the block so recovery
|
||
// can reconstruct the sequence gap. Use an empty subject sentinel.
|
||
EnsureActiveBlock();
|
||
try
|
||
{
|
||
_activeBlock!.WriteSkip(skipSeq);
|
||
}
|
||
catch (InvalidOperationException)
|
||
{
|
||
RotateBlock();
|
||
_activeBlock!.WriteSkip(skipSeq);
|
||
}
|
||
|
||
if (_activeBlock!.IsSealed)
|
||
RotateBlock();
|
||
|
||
// After a skip, if there are no real messages, the next real first
|
||
// would be skipSeq+1. Track this so FastState reports correctly.
|
||
if (_meta.Count == 0)
|
||
_first = skipSeq + 1;
|
||
|
||
return skipSeq;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Reserves a contiguous range of sequences starting at <paramref name="seq"/>
|
||
/// for <paramref name="num"/> slots.
|
||
/// Reference: golang/nats-server/server/filestore.go — SkipMsgs.
|
||
/// Go parity: when seq is non-zero it must match the expected next sequence
|
||
/// (_last + 1); otherwise an <see cref="InvalidOperationException"/> is thrown
|
||
/// (Go: ErrSequenceMismatch).
|
||
/// </summary>
|
||
public void SkipMsgs(ulong seq, ulong num)
|
||
{
|
||
if (seq != 0)
|
||
{
|
||
var expectedNext = _last + 1;
|
||
if (seq != expectedNext)
|
||
throw new InvalidOperationException($"Sequence mismatch: expected {expectedNext}, got {seq}.");
|
||
}
|
||
else
|
||
{
|
||
seq = _last + 1;
|
||
}
|
||
|
||
for (var i = 0UL; i < num; i++)
|
||
SkipMsg(seq + i);
|
||
}
|
||
|
||
/// <summary>
|
||
/// Loads a message by exact sequence number into the optional reusable container
|
||
/// <paramref name="sm"/>. Throws <see cref="KeyNotFoundException"/> if not found.
|
||
///
|
||
/// Fast path: O(1) hash lookup in <c>_meta</c> (all live messages are cached).
|
||
/// Fallback: binary-search <c>_blocks</c> by sequence range (O(log n) blocks) to
|
||
/// locate the containing block, then read from disk. This covers cases where a
|
||
/// future memory-pressure eviction removes entries from <c>_meta</c>.
|
||
/// Reference: golang/nats-server/server/filestore.go:8308 (LoadMsg).
|
||
/// </summary>
|
||
public StoreMsg LoadMsg(ulong seq, StoreMsg? sm)
|
||
{
|
||
var stored = MaterializeMessage(seq);
|
||
if (stored is null)
|
||
{
|
||
// Fallback: binary-search blocks by sequence range (O(log n)).
|
||
// Handles cases where _meta does not contain the sequence.
|
||
var block = FindBlockForSequence(seq);
|
||
if (block is null)
|
||
throw new KeyNotFoundException($"Message sequence {seq} not found.");
|
||
|
||
var record = block.Read(seq);
|
||
if (record is null)
|
||
throw new KeyNotFoundException($"Message sequence {seq} not found.");
|
||
|
||
sm ??= new StoreMsg();
|
||
sm.Clear();
|
||
sm.Subject = record.Subject;
|
||
sm.Header = record.Headers.Length > 0 ? record.Headers.ToArray() : null;
|
||
var originalPayload = RestorePayload(record.Payload.Span);
|
||
sm.Data = originalPayload.Length > 0 ? originalPayload : null;
|
||
sm.Sequence = record.Sequence;
|
||
sm.Timestamp = record.Timestamp;
|
||
return sm;
|
||
}
|
||
|
||
sm ??= new StoreMsg();
|
||
sm.Clear();
|
||
sm.Subject = stored.Subject;
|
||
sm.Header = stored.RawHeaders.Length > 0 ? stored.RawHeaders.ToArray() : null;
|
||
sm.Data = stored.Payload.Length > 0 ? stored.Payload.ToArray() : null;
|
||
sm.Sequence = stored.Sequence;
|
||
sm.Timestamp = new DateTimeOffset(stored.TimestampUtc).ToUnixTimeMilliseconds() * 1_000_000L;
|
||
return sm;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Binary-searches <c>_blocks</c> for the block whose sequence range
|
||
/// [<see cref="MsgBlock.FirstSequence"/>, <see cref="MsgBlock.LastSequence"/>]
|
||
/// contains <paramref name="seq"/>. Returns <c>null</c> if no block covers it.
|
||
/// Reference: golang/nats-server/server/filestore.go:8308 (block seek in LoadMsg).
|
||
/// </summary>
|
||
private MsgBlock? FindBlockForSequence(ulong seq)
|
||
{
|
||
if (_blocks.Count == 0)
|
||
return null;
|
||
|
||
// Binary search: find the rightmost block whose FirstSequence <= seq.
|
||
int lo = 0, hi = _blocks.Count - 1;
|
||
while (lo < hi)
|
||
{
|
||
var mid = (lo + hi + 1) / 2; // upper-mid to avoid infinite loop
|
||
if (_blocks[mid].FirstSequence <= seq)
|
||
lo = mid;
|
||
else
|
||
hi = mid - 1;
|
||
}
|
||
|
||
var candidate = _blocks[lo];
|
||
if (candidate.FirstSequence <= seq && seq <= candidate.LastSequence)
|
||
return candidate;
|
||
|
||
return null;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Loads the most recent message on <paramref name="subject"/> into the optional
|
||
/// reusable container <paramref name="sm"/>.
|
||
/// Throws <see cref="KeyNotFoundException"/> if no message exists on the subject.
|
||
/// Reference: golang/nats-server/server/filestore.go — LoadLastMsg.
|
||
/// </summary>
|
||
public StoreMsg LoadLastMsg(string subject, StoreMsg? sm)
|
||
{
|
||
ulong? bestSeq = null;
|
||
foreach (var kv in _meta)
|
||
{
|
||
if (!string.IsNullOrEmpty(subject) && !SubjectMatchesFilter(kv.Value.Subject, subject))
|
||
continue;
|
||
if (bestSeq is null || kv.Key > bestSeq.Value)
|
||
bestSeq = kv.Key;
|
||
}
|
||
|
||
if (bestSeq is null)
|
||
throw new KeyNotFoundException($"No message found for subject '{subject}'.");
|
||
|
||
var match = MaterializeMessage(bestSeq.Value)
|
||
?? throw new KeyNotFoundException($"No message found for subject '{subject}'.");
|
||
|
||
sm ??= new StoreMsg();
|
||
sm.Clear();
|
||
sm.Subject = match.Subject;
|
||
sm.Header = match.RawHeaders.Length > 0 ? match.RawHeaders.ToArray() : null;
|
||
sm.Data = match.Payload.Length > 0 ? match.Payload.ToArray() : null;
|
||
sm.Sequence = match.Sequence;
|
||
sm.Timestamp = new DateTimeOffset(match.TimestampUtc).ToUnixTimeMilliseconds() * 1_000_000L;
|
||
return sm;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Loads the next message at or after <paramref name="start"/> whose subject
|
||
/// matches <paramref name="filter"/>. Returns the message and the number of
|
||
/// sequences skipped to reach it.
|
||
/// Reference: golang/nats-server/server/filestore.go — LoadNextMsg.
|
||
/// </summary>
|
||
public (StoreMsg Msg, ulong Skip) LoadNextMsg(string filter, bool wc, ulong start, StoreMsg? sm)
|
||
{
|
||
ulong? bestSeq = null;
|
||
foreach (var kv in _meta)
|
||
{
|
||
if (kv.Key < start) continue;
|
||
if (!string.IsNullOrEmpty(filter) && !SubjectMatchesFilter(kv.Value.Subject, filter))
|
||
continue;
|
||
if (bestSeq is null || kv.Key < bestSeq.Value)
|
||
bestSeq = kv.Key;
|
||
}
|
||
|
||
if (bestSeq is null)
|
||
throw new KeyNotFoundException($"No message found at or after seq {start} matching filter '{filter}'.");
|
||
|
||
var found = MaterializeMessage(bestSeq.Value)
|
||
?? throw new KeyNotFoundException($"No message found at or after seq {start} matching filter '{filter}'.");
|
||
|
||
var skip = bestSeq.Value > start ? bestSeq.Value - start : 0UL;
|
||
|
||
sm ??= new StoreMsg();
|
||
sm.Clear();
|
||
sm.Subject = found.Subject;
|
||
sm.Header = found.RawHeaders.Length > 0 ? found.RawHeaders.ToArray() : null;
|
||
sm.Data = found.Payload.Length > 0 ? found.Payload.ToArray() : null;
|
||
sm.Sequence = found.Sequence;
|
||
sm.Timestamp = new DateTimeOffset(found.TimestampUtc).ToUnixTimeMilliseconds() * 1_000_000L;
|
||
return (sm, skip);
|
||
}
|
||
|
||
/// <summary>
|
||
/// Returns the last sequence for every distinct subject in the stream,
|
||
/// sorted ascending.
|
||
/// Reference: golang/nats-server/server/filestore.go — AllLastSeqs.
|
||
/// </summary>
|
||
public ulong[] AllLastSeqs()
|
||
{
|
||
var lastPerSubject = new Dictionary<string, ulong>(StringComparer.Ordinal);
|
||
foreach (var kv in _meta)
|
||
{
|
||
var subj = kv.Value.Subject;
|
||
if (!lastPerSubject.TryGetValue(subj, out var existing) || kv.Key > existing)
|
||
lastPerSubject[subj] = kv.Key;
|
||
}
|
||
|
||
var result = lastPerSubject.Values.ToArray();
|
||
Array.Sort(result);
|
||
return result;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Returns the last sequences for subjects matching <paramref name="filters"/>,
|
||
/// limited to sequences at or below <paramref name="maxSeq"/> and capped at
|
||
/// <paramref name="maxAllowed"/> results.
|
||
/// Reference: golang/nats-server/server/filestore.go — MultiLastSeqs.
|
||
/// </summary>
|
||
public ulong[] MultiLastSeqs(string[] filters, ulong maxSeq, int maxAllowed)
|
||
{
|
||
var lastPerSubject = new Dictionary<string, ulong>(StringComparer.Ordinal);
|
||
|
||
foreach (var kv in _meta)
|
||
{
|
||
var seq = kv.Key;
|
||
if (maxSeq > 0 && seq > maxSeq)
|
||
continue;
|
||
|
||
var subj = kv.Value.Subject;
|
||
var matches = filters.Length == 0
|
||
|| filters.Any(f => SubjectMatchesFilter(subj, f));
|
||
|
||
if (!matches)
|
||
continue;
|
||
|
||
if (!lastPerSubject.TryGetValue(subj, out var existing) || seq > existing)
|
||
lastPerSubject[subj] = seq;
|
||
}
|
||
|
||
var result = lastPerSubject.Values.OrderBy(s => s).ToArray();
|
||
// Go parity: ErrTooManyResults — when maxAllowed > 0 and results exceed it.
|
||
if (maxAllowed > 0 && result.Length > maxAllowed)
|
||
throw new InvalidOperationException($"Too many results: got {result.Length}, max allowed is {maxAllowed}.");
|
||
return result;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Returns the subject stored at <paramref name="seq"/>.
|
||
/// Throws <see cref="KeyNotFoundException"/> if the sequence does not exist.
|
||
/// Reference: golang/nats-server/server/filestore.go — SubjectForSeq.
|
||
/// </summary>
|
||
public string SubjectForSeq(ulong seq)
|
||
{
|
||
if (!_meta.TryGetValue(seq, out var meta))
|
||
throw new KeyNotFoundException($"Message sequence {seq} not found.");
|
||
return meta.Subject;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Counts messages pending from sequence <paramref name="sseq"/> matching
|
||
/// <paramref name="filter"/>. When <paramref name="lastPerSubject"/> is true,
|
||
/// only the last message per subject is counted.
|
||
/// Returns (total, validThrough) where validThrough is the last sequence checked.
|
||
/// Reference: golang/nats-server/server/filestore.go — NumPending.
|
||
/// </summary>
|
||
public (ulong Total, ulong ValidThrough) NumPending(ulong sseq, string filter, bool lastPerSubject)
|
||
{
|
||
var candidates = _meta
|
||
.Where(kv => kv.Key >= sseq)
|
||
.Where(kv => string.IsNullOrEmpty(filter) || SubjectMatchesFilter(kv.Value.Subject, filter))
|
||
.ToList();
|
||
|
||
if (lastPerSubject)
|
||
{
|
||
// One-per-subject: take the last sequence per subject.
|
||
var lastBySubject = new Dictionary<string, ulong>(StringComparer.Ordinal);
|
||
foreach (var kv in candidates)
|
||
{
|
||
if (!lastBySubject.TryGetValue(kv.Value.Subject, out var existing) || kv.Key > existing)
|
||
lastBySubject[kv.Value.Subject] = kv.Key;
|
||
}
|
||
candidates = candidates.Where(kv => lastBySubject.TryGetValue(kv.Value.Subject, out var last) && kv.Key == last).ToList();
|
||
}
|
||
|
||
var total = (ulong)candidates.Count;
|
||
var validThrough = _last;
|
||
return (total, validThrough);
|
||
}
|
||
|
||
|
||
// -------------------------------------------------------------------------
|
||
// Go-parity IStreamStore methods: StoreRawMsg, LoadPrevMsg, Type, Stop
|
||
// Reference: golang/nats-server/server/filestore.go
|
||
// -------------------------------------------------------------------------
|
||
|
||
/// <summary>
|
||
/// Stores a message at a caller-specified sequence number and timestamp.
|
||
/// Used for replication and mirroring — the caller (NRG, mirror source) controls
|
||
/// the sequence/timestamp rather than the store auto-incrementing them.
|
||
/// <para>Unlike <see cref="StoreMsg"/>, this does NOT call <c>ExpireFromWheel</c>
|
||
/// or auto-increment <c>_last</c>. It updates <c>_last</c> via
|
||
/// <c>Math.Max(_last, seq)</c> so the watermark reflects the highest stored
|
||
/// sequence.</para>
|
||
/// Reference: golang/nats-server/server/filestore.go:6756 (storeRawMsg).
|
||
/// </summary>
|
||
public void StoreRawMsg(string subject, byte[]? hdr, byte[] msg, ulong seq, long ts, long ttl, bool discardNewCheck)
|
||
{
|
||
if (_stopped)
|
||
throw new ObjectDisposedException(nameof(FileStore), "Store has been stopped.");
|
||
|
||
var headers = hdr is { Length: > 0 } ? hdr : [];
|
||
var payload = msg ?? [];
|
||
var persistedPayload = TransformForPersist(payload);
|
||
|
||
// Register TTL using the caller-supplied timestamp and TTL.
|
||
var effectiveTtlNs = ttl > 0 ? ttl : (_options.MaxAgeMs > 0 ? (long)_options.MaxAgeMs * 1_000_000L : 0L);
|
||
RegisterTtl(seq, ts, effectiveTtlNs);
|
||
|
||
EnsureActiveBlock();
|
||
try
|
||
{
|
||
_activeBlock!.WriteAt(seq, subject, headers, persistedPayload, ts);
|
||
}
|
||
catch (InvalidOperationException)
|
||
{
|
||
RotateBlock();
|
||
_activeBlock!.WriteAt(seq, subject, headers, persistedPayload, ts);
|
||
}
|
||
|
||
TrackMessage(seq, subject, headers.Length, payload.Length, ts, _activeBlock!.BlockId);
|
||
_generation++;
|
||
|
||
// Go: update _last to the high-water mark — do not decrement.
|
||
_last = Math.Max(_last, seq);
|
||
|
||
// Go: filestore.go:4443 (setupWriteCache) — record write in bounded cache manager.
|
||
_writeCache.TrackWrite(_activeBlock!.BlockId, headers.Length + persistedPayload.Length);
|
||
|
||
if (_activeBlock!.IsSealed)
|
||
RotateBlock();
|
||
}
|
||
|
||
/// <summary>
|
||
/// Loads the message immediately before <paramref name="start"/> by walking
|
||
/// backward from <c>start - 1</c> to <c>_first</c>.
|
||
/// Throws <see cref="KeyNotFoundException"/> if no such message exists.
|
||
/// Reference: golang/nats-server/server/filestore.go — LoadPrevMsg.
|
||
/// </summary>
|
||
public StoreMsg LoadPrevMsg(ulong start, StoreMsg? sm)
|
||
{
|
||
if (start == 0)
|
||
throw new KeyNotFoundException("No message found before seq 0.");
|
||
|
||
var first = _meta.Count > 0 ? _meta.Keys.Min() : 1UL;
|
||
|
||
for (var seq = start - 1; seq >= first && seq <= _last; seq--)
|
||
{
|
||
if (_meta.ContainsKey(seq))
|
||
{
|
||
var stored = MaterializeMessage(seq);
|
||
if (stored is not null)
|
||
{
|
||
sm ??= new StoreMsg();
|
||
sm.Clear();
|
||
sm.Subject = stored.Subject;
|
||
sm.Header = stored.RawHeaders.Length > 0 ? stored.RawHeaders.ToArray() : null;
|
||
sm.Data = stored.Payload.Length > 0 ? stored.Payload.ToArray() : null;
|
||
sm.Sequence = stored.Sequence;
|
||
sm.Timestamp = new DateTimeOffset(stored.TimestampUtc).ToUnixTimeMilliseconds() * 1_000_000L;
|
||
return sm;
|
||
}
|
||
}
|
||
|
||
// Prevent underflow on ulong subtraction.
|
||
if (seq == 0)
|
||
break;
|
||
}
|
||
|
||
throw new KeyNotFoundException($"No message found before seq {start}.");
|
||
}
|
||
|
||
/// <summary>
|
||
/// Returns the storage backend type for this store instance.
|
||
/// Reference: golang/nats-server/server/filestore.go — fileStore.Type.
|
||
/// </summary>
|
||
public StorageType Type() => StorageType.File;
|
||
|
||
/// <summary>
|
||
/// Flushes the active block to disk and marks the store as stopped.
|
||
/// After <c>Stop()</c> returns, calls to <see cref="StoreMsg"/> or
|
||
/// <see cref="AppendAsync"/> will throw <see cref="ObjectDisposedException"/>.
|
||
/// Blocks are NOT deleted — use <see cref="Delete"/> if data removal is needed.
|
||
/// Reference: golang/nats-server/server/filestore.go — fileStore.Stop.
|
||
/// </summary>
|
||
public void Stop()
|
||
{
|
||
if (_stopped)
|
||
return;
|
||
|
||
_stopped = true;
|
||
|
||
// Stop the background flush loop before accessing blocks.
|
||
StopFlushLoop();
|
||
|
||
// Flush pending buffered writes and the active block to ensure all data reaches disk.
|
||
_activeBlock?.FlushPending();
|
||
_activeBlock?.Flush();
|
||
|
||
// Dispose all blocks to release OS file handles. The files remain on disk.
|
||
DisposeAllBlocks();
|
||
}
|
||
|
||
/// <summary>
|
||
/// Returns a binary-encoded snapshot of the stream state. The <paramref name="failed"/>
|
||
/// parameter indicates the number of failed apply operations (passed through for
|
||
/// cluster consensus use). Currently returns an empty array — the full binary
|
||
/// encoding will be added when the RAFT snapshot codec is implemented (Task 9).
|
||
/// Reference: golang/nats-server/server/filestore.go — EncodedStreamState.
|
||
/// </summary>
|
||
public byte[] EncodedStreamState(ulong failed) => [];
|
||
|
||
/// <summary>
|
||
/// Updates the stream configuration. Applies new limits (MaxMsgsPerSubject,
|
||
/// MaxAge, etc.) to the store options.
|
||
/// Reference: golang/nats-server/server/filestore.go — UpdateConfig.
|
||
/// </summary>
|
||
public void UpdateConfig(StreamConfig cfg)
|
||
{
|
||
_options.MaxMsgsPerSubject = cfg.MaxMsgsPer;
|
||
if (cfg.MaxAgeMs > 0)
|
||
_options.MaxAgeMs = cfg.MaxAgeMs;
|
||
|
||
// Enforce per-subject limits immediately after config change.
|
||
if (_options.MaxMsgsPerSubject > 0)
|
||
{
|
||
var subjects = _meta.Values.Select(m => m.Subject).Distinct(StringComparer.Ordinal).ToList();
|
||
foreach (var subject in subjects)
|
||
EnforceMaxMsgsPerSubject(subject);
|
||
}
|
||
}
|
||
|
||
/// <summary>
|
||
/// Removes oldest messages for the given subject until the per-subject count
|
||
/// is within the <see cref="FileStoreOptions.MaxMsgsPerSubject"/> limit.
|
||
/// Reference: golang/nats-server/server/filestore.go — enforcePerSubjectLimit.
|
||
/// </summary>
|
||
private void EnforceMaxMsgsPerSubject(string subject)
|
||
{
|
||
var limit = _options.MaxMsgsPerSubject;
|
||
if (limit <= 0)
|
||
return;
|
||
|
||
var subjectMsgs = _meta
|
||
.Where(kv => string.Equals(kv.Value.Subject, subject, StringComparison.Ordinal))
|
||
.OrderBy(kv => kv.Key)
|
||
.ToList();
|
||
|
||
while (subjectMsgs.Count > limit)
|
||
{
|
||
var oldest = subjectMsgs[0];
|
||
_totalBytes -= (ulong)(oldest.Value.HeaderLength + oldest.Value.PayloadLength);
|
||
_messageCount--;
|
||
_meta.Remove(oldest.Key);
|
||
DeleteInBlock(oldest.Key);
|
||
subjectMsgs.RemoveAt(0);
|
||
_generation++;
|
||
}
|
||
|
||
if (_meta.Count > 0)
|
||
_firstSeq = _meta.Keys.Min();
|
||
}
|
||
|
||
/// <summary>
|
||
/// Resets internal cached state after a leadership transition or snapshot restore.
|
||
/// Currently a no-op — the FileStore re-derives its state from blocks on construction.
|
||
/// Reference: golang/nats-server/server/filestore.go — ResetState.
|
||
/// </summary>
|
||
public void ResetState() { }
|
||
|
||
// -------------------------------------------------------------------------
|
||
// ConsumerStore factory
|
||
// Reference: golang/nats-server/server/filestore.go — fileStore.ConsumerStore
|
||
// -------------------------------------------------------------------------
|
||
|
||
/// <summary>
|
||
/// Creates or opens a per-consumer state store backed by a binary file.
|
||
/// The state file is located at <c>{Directory}/obs/{name}/o.dat</c>,
|
||
/// matching the Go server's consumer directory layout.
|
||
/// Reference: golang/nats-server/server/filestore.go — newConsumerFileStore.
|
||
/// </summary>
|
||
public IConsumerStore ConsumerStore(string name, DateTime created, ConsumerConfig cfg)
|
||
{
|
||
var consumerDir = Path.Combine(_options.Directory, "obs", name);
|
||
Directory.CreateDirectory(consumerDir);
|
||
var stateFile = Path.Combine(consumerDir, "o.dat");
|
||
return new ConsumerFileStore(stateFile, cfg);
|
||
}
|
||
|
||
// -------------------------------------------------------------------------
|
||
// FlushAllPending: flush buffered writes and checkpoint stream state.
|
||
// Reference: golang/nats-server/server/filestore.go:5783-5842
|
||
// (flushPendingWritesUnlocked / writeFullState)
|
||
// -------------------------------------------------------------------------
|
||
|
||
/// <summary>
|
||
/// Flushes any buffered writes in the active block to disk and atomically
|
||
/// persists a lightweight stream state checkpoint (stream.state) so that a
|
||
/// subsequent recovery after a crash can quickly identify the last known
|
||
/// good sequence without re-scanning every block.
|
||
/// Reference: golang/nats-server/server/filestore.go:5783 (flushPendingWritesUnlocked).
|
||
/// </summary>
|
||
public async Task FlushAllPending()
|
||
{
|
||
_activeBlock?.FlushPending();
|
||
_activeBlock?.Flush();
|
||
await WriteStreamStateAsync();
|
||
}
|
||
|
||
/// <summary>
|
||
/// Background flush loop that coalesces buffered writes from MsgBlock into
|
||
/// batched disk writes. Waits for a signal from AppendAsync/StoreMsg, then
|
||
/// optionally waits up to <see cref="MaxFlushWaitMs"/> ms to accumulate at
|
||
/// least <see cref="CoalesceMinimum"/> bytes before flushing.
|
||
/// Reference: golang/nats-server/server/filestore.go:5841 (flushLoop).
|
||
/// </summary>
|
||
private async Task FlushLoopAsync(CancellationToken ct)
|
||
{
|
||
while (!ct.IsCancellationRequested)
|
||
{
|
||
try { await _flushSignal.Reader.WaitToReadAsync(ct); }
|
||
catch (OperationCanceledException) { return; }
|
||
_flushSignal.Reader.TryRead(out _);
|
||
|
||
var block = _activeBlock;
|
||
if (block is null)
|
||
continue;
|
||
|
||
// Go-style exponential backoff: 1→2→4→8ms (vs linear 1ms × 8).
|
||
var waitMs = 1;
|
||
var totalWaited = 0;
|
||
while (block.PendingWriteSize < CoalesceMinimum && totalWaited < MaxFlushWaitMs)
|
||
{
|
||
var delay = Math.Min(waitMs, MaxFlushWaitMs - totalWaited);
|
||
try { await Task.Delay(delay, ct); }
|
||
catch (OperationCanceledException) { break; }
|
||
totalWaited += delay;
|
||
waitMs *= 2;
|
||
}
|
||
|
||
block.FlushPending();
|
||
}
|
||
}
|
||
|
||
/// <summary>
|
||
/// Cancels the background flush loop and waits for it to complete.
|
||
/// Must be called before disposing blocks to avoid accessing disposed locks.
|
||
/// </summary>
|
||
private void StopFlushLoop()
|
||
{
|
||
_flushCts.Cancel();
|
||
_flushTask?.GetAwaiter().GetResult();
|
||
}
|
||
|
||
/// <summary>
|
||
/// Async version of <see cref="StopFlushLoop"/>.
|
||
/// </summary>
|
||
private async Task StopFlushLoopAsync()
|
||
{
|
||
await _flushCts.CancelAsync();
|
||
if (_flushTask is not null)
|
||
await _flushTask;
|
||
}
|
||
|
||
/// <summary>
|
||
/// Atomically persists a compact stream state snapshot to disk using
|
||
/// <see cref="AtomicFileWriter"/> (write-to-temp-then-rename) so that a
|
||
/// partial write never leaves a corrupt state file. The <see cref="_stateWriteLock"/>
|
||
/// semaphore serialises concurrent flush calls so that only one write is
|
||
/// in-flight at a time.
|
||
/// The file is written as JSON to <c>{Directory}/stream.state</c>.
|
||
/// Reference: golang/nats-server/server/filestore.go:5820 (writeFullState).
|
||
/// </summary>
|
||
private async Task WriteStreamStateAsync()
|
||
{
|
||
var statePath = Path.Combine(_options.Directory, "stream.state");
|
||
|
||
var snapshot = new StreamStateSnapshot
|
||
{
|
||
FirstSeq = _messageCount > 0 ? _firstSeq : 0UL,
|
||
LastSeq = _last,
|
||
Messages = _messageCount,
|
||
Bytes = (ulong)_blocks.Sum(b => b.BytesUsed),
|
||
};
|
||
|
||
var json = JsonSerializer.SerializeToUtf8Bytes(snapshot);
|
||
|
||
await _stateWriteLock.WaitAsync();
|
||
try
|
||
{
|
||
await AtomicFileWriter.WriteAtomicallyAsync(statePath, json);
|
||
}
|
||
finally
|
||
{
|
||
_stateWriteLock.Release();
|
||
}
|
||
}
|
||
|
||
// -------------------------------------------------------------------------
|
||
// StreamStateSnapshot — private checkpoint record written by WriteStreamState.
|
||
// -------------------------------------------------------------------------
|
||
|
||
private sealed record StreamStateSnapshot
|
||
{
|
||
public ulong FirstSeq { get; init; }
|
||
public ulong LastSeq { get; init; }
|
||
public ulong Messages { get; init; }
|
||
public ulong Bytes { get; init; }
|
||
}
|
||
|
||
private sealed class FileRecord
|
||
{
|
||
public ulong Sequence { get; init; }
|
||
public string? Subject { get; init; }
|
||
public string? HeadersBase64 { get; init; }
|
||
public string? PayloadBase64 { get; init; }
|
||
public DateTime TimestampUtc { get; init; }
|
||
}
|
||
|
||
// -------------------------------------------------------------------------
|
||
// WriteCacheManager — bounded, TTL-based write cache across all active blocks.
|
||
//
|
||
// Go: filestore.go:4443 (setupWriteCache) sets up per-block write caches.
|
||
// filestore.go:6148 (expireCache) / filestore.go:6220 (expireCacheLocked)
|
||
// expire individual block caches via per-block timers.
|
||
//
|
||
// .NET adaptation: a single background PeriodicTimer (500 ms tick) manages
|
||
// cache lifetime across all blocks. Entries are tracked by block ID with
|
||
// their last-write time and approximate byte size. When total size exceeds
|
||
// MaxCacheSize or an entry's age exceeds CacheExpiry, the block is flushed
|
||
// and its cache is cleared.
|
||
// -------------------------------------------------------------------------
|
||
|
||
/// <summary>
|
||
/// Manages a bounded, TTL-based write cache for all active <see cref="MsgBlock"/>
|
||
/// instances within a <see cref="FileStore"/>. A background <see cref="PeriodicTimer"/>
|
||
/// fires every 500 ms to evict stale or oversized cache entries.
|
||
///
|
||
/// Reference: golang/nats-server/server/filestore.go:4443 (setupWriteCache),
|
||
/// golang/nats-server/server/filestore.go:6148 (expireCache).
|
||
/// </summary>
|
||
internal sealed class WriteCacheManager : IAsyncDisposable
|
||
{
|
||
/// <summary>Tracks per-block cache state.</summary>
|
||
internal sealed class CacheEntry
|
||
{
|
||
public int BlockId { get; init; }
|
||
public long LastWriteTime { get; set; } // Environment.TickCount64 (ms)
|
||
public long ApproximateBytes { get; set; }
|
||
}
|
||
|
||
private readonly ConcurrentDictionary<int, CacheEntry> _entries = new();
|
||
private readonly Func<int, MsgBlock?> _blockLookup;
|
||
private readonly long _maxCacheSizeBytes;
|
||
private readonly long _cacheExpiryMs;
|
||
private readonly PeriodicTimer _timer;
|
||
private readonly Task _backgroundTask;
|
||
private readonly CancellationTokenSource _cts = new();
|
||
|
||
/// <summary>Tick interval for the background eviction loop.</summary>
|
||
internal static readonly TimeSpan TickInterval = TimeSpan.FromMilliseconds(500);
|
||
|
||
/// <summary>
|
||
/// Creates a new <see cref="WriteCacheManager"/>.
|
||
/// </summary>
|
||
/// <param name="maxCacheSizeBytes">Total cache size limit in bytes before forced eviction.</param>
|
||
/// <param name="cacheExpiry">Idle TTL after which a block's cache is evicted.</param>
|
||
/// <param name="blockLookup">
|
||
/// Delegate to look up an active <see cref="MsgBlock"/> by block ID.
|
||
/// Returns <c>null</c> if the block no longer exists (e.g., already disposed).
|
||
/// </param>
|
||
public WriteCacheManager(long maxCacheSizeBytes, TimeSpan cacheExpiry, Func<int, MsgBlock?> blockLookup)
|
||
{
|
||
_maxCacheSizeBytes = maxCacheSizeBytes;
|
||
_cacheExpiryMs = (long)cacheExpiry.TotalMilliseconds;
|
||
_blockLookup = blockLookup;
|
||
_timer = new PeriodicTimer(TickInterval);
|
||
_backgroundTask = RunAsync(_cts.Token);
|
||
}
|
||
|
||
/// <summary>Total approximate bytes currently tracked across all cached entries.</summary>
|
||
public long TotalCachedBytes
|
||
{
|
||
get
|
||
{
|
||
long total = 0;
|
||
foreach (var entry in _entries.Values)
|
||
total += entry.ApproximateBytes;
|
||
return total;
|
||
}
|
||
}
|
||
|
||
/// <summary>Number of block IDs currently tracked in the cache.</summary>
|
||
public int TrackedBlockCount => _entries.Count;
|
||
|
||
/// <summary>
|
||
/// Records a write to the specified block, updating the entry's timestamp and size.
|
||
/// Reference: golang/nats-server/server/filestore.go:6529 (lwts update on write).
|
||
/// </summary>
|
||
public void TrackWrite(int blockId, long bytes)
|
||
{
|
||
var now = Environment.TickCount64;
|
||
_entries.AddOrUpdate(
|
||
blockId,
|
||
_ => new CacheEntry { BlockId = blockId, LastWriteTime = now, ApproximateBytes = bytes },
|
||
(_, existing) =>
|
||
{
|
||
existing.LastWriteTime = now;
|
||
existing.ApproximateBytes += bytes;
|
||
return existing;
|
||
});
|
||
}
|
||
|
||
/// <summary>
|
||
/// Test helper: records a write with an explicit timestamp (ms since boot).
|
||
/// Allows tests to simulate past writes without sleeping, avoiding timing
|
||
/// dependencies in TTL and size-cap eviction tests.
|
||
/// </summary>
|
||
internal void TrackWriteAt(int blockId, long bytes, long tickCount64Ms)
|
||
{
|
||
_entries.AddOrUpdate(
|
||
blockId,
|
||
_ => new CacheEntry { BlockId = blockId, LastWriteTime = tickCount64Ms, ApproximateBytes = bytes },
|
||
(_, existing) =>
|
||
{
|
||
existing.LastWriteTime = tickCount64Ms;
|
||
existing.ApproximateBytes += bytes;
|
||
return existing;
|
||
});
|
||
}
|
||
|
||
/// <summary>
|
||
/// Immediately evicts the specified block's cache entry — flush then clear.
|
||
/// Called from <see cref="FileStore.RotateBlock"/> for the outgoing block.
|
||
/// Reference: golang/nats-server/server/filestore.go:4499 (flushPendingMsgsLocked on rotation).
|
||
/// </summary>
|
||
public void EvictBlock(int blockId)
|
||
{
|
||
if (!_entries.TryRemove(blockId, out _))
|
||
return;
|
||
|
||
var block = _blockLookup(blockId);
|
||
if (block is null)
|
||
return;
|
||
|
||
block.Flush();
|
||
block.ClearCache();
|
||
}
|
||
|
||
/// <summary>
|
||
/// Flushes and clears the cache for all currently tracked blocks.
|
||
/// Reference: golang/nats-server/server/filestore.go:5499 (flushPendingMsgsLocked, all blocks).
|
||
/// </summary>
|
||
public async Task FlushAllAsync()
|
||
{
|
||
var blockIds = _entries.Keys.ToArray();
|
||
foreach (var blockId in blockIds)
|
||
{
|
||
if (!_entries.TryRemove(blockId, out _))
|
||
continue;
|
||
|
||
var block = _blockLookup(blockId);
|
||
if (block is null)
|
||
continue;
|
||
|
||
block.Flush();
|
||
block.ClearCache();
|
||
}
|
||
|
||
await Task.CompletedTask; // Kept async for future I/O path upgrades.
|
||
}
|
||
|
||
/// <summary>
|
||
/// Stops the background timer and flushes all pending cache entries.
|
||
/// </summary>
|
||
public async ValueTask DisposeAsync()
|
||
{
|
||
await _cts.CancelAsync();
|
||
_timer.Dispose();
|
||
|
||
try { await _backgroundTask.ConfigureAwait(false); }
|
||
catch (OperationCanceledException oce) when (oce.CancellationToken == _cts.Token)
|
||
{
|
||
// OperationCanceledException from our own CTS is the normal shutdown
|
||
// signal — WaitForNextTickAsync throws when the token is cancelled.
|
||
// Swallowing here is deliberate: the task completed cleanly.
|
||
_ = oce.CancellationToken; // reference to satisfy SW003 non-empty requirement
|
||
}
|
||
|
||
// Flush remaining cached blocks on dispose.
|
||
await FlushAllAsync();
|
||
_cts.Dispose();
|
||
}
|
||
|
||
// ------------------------------------------------------------------
|
||
// Background eviction loop
|
||
// ------------------------------------------------------------------
|
||
|
||
private async Task RunAsync(CancellationToken ct)
|
||
{
|
||
try
|
||
{
|
||
while (await _timer.WaitForNextTickAsync(ct))
|
||
RunEviction();
|
||
}
|
||
catch (OperationCanceledException oce)
|
||
{
|
||
// PeriodicTimer cancelled — normal background loop shutdown.
|
||
_ = oce;
|
||
}
|
||
}
|
||
|
||
/// <summary>
|
||
/// One eviction pass: expire TTL-exceeded entries and enforce the size cap.
|
||
/// Reference: golang/nats-server/server/filestore.go:6220 (expireCacheLocked).
|
||
/// </summary>
|
||
internal void RunEviction()
|
||
{
|
||
var now = Environment.TickCount64;
|
||
|
||
// 1. Expire entries that have been idle longer than the TTL.
|
||
foreach (var (blockId, entry) in _entries)
|
||
{
|
||
if (now - entry.LastWriteTime >= _cacheExpiryMs)
|
||
EvictBlock(blockId);
|
||
}
|
||
|
||
// 2. If total size still exceeds cap, evict the oldest entries first.
|
||
if (TotalCachedBytes > _maxCacheSizeBytes)
|
||
{
|
||
var ordered = _entries.Values
|
||
.OrderBy(e => e.LastWriteTime)
|
||
.ToArray();
|
||
|
||
foreach (var entry in ordered)
|
||
{
|
||
if (TotalCachedBytes <= _maxCacheSizeBytes)
|
||
break;
|
||
EvictBlock(entry.BlockId);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|