feat(localdb): gRPC sync adapters, background service, replication DI

Claude-Session: https://claude.ai/code/session_01BL2Vu1ESDQ9SCN4gVKkdts
2026-07-17 23:01:29 -04:00
parent 183901e8ac
commit a64fc26391
7 changed files with 701 additions and 0 deletions
@@ -0,0 +1,62 @@
+using Grpc.Core;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using ZB.MOM.WW.LocalDb.Contracts;
+using ZB.MOM.WW.LocalDb.Internal;
+using ZB.MOM.WW.LocalDb.Replication.Internal;
+
+namespace ZB.MOM.WW.LocalDb.Replication;
+
+/// <summary>
+/// The passive (server) side of replication: a gRPC service that accepts an inbound bidirectional
+/// <c>Sync</c> stream and runs the symmetric <see cref="SyncSession"/> over it. Registered as a
+/// singleton so its single-stream guard spans concurrent calls (a node syncs with exactly one peer).
+/// </summary>
+public sealed class LocalDbSyncService : LocalDbSync.LocalDbSyncBase
+{
+    private readonly SqliteLocalDb _db;
+    private readonly ReplicationOptions _options;
+    private readonly ILoggerFactory _loggerFactory;
+
+    // 0 = idle, 1 = a stream is active. Interlocked-guarded across concurrent calls (singleton service).
+    private int _active;
+
+    public LocalDbSyncService(ILocalDb db, IOptions<ReplicationOptions> options, ILoggerFactory loggerFactory)
+    {
+        _db = db as SqliteLocalDb
+            ?? throw new InvalidOperationException(
+                $"LocalDbSyncService requires the ILocalDb registered by AddZbLocalDb (a {nameof(SqliteLocalDb)}); " +
+                $"got {db.GetType().FullName}.");
+        _options = options.Value;
+        _loggerFactory = loggerFactory;
+    }
+
+    public override async Task Sync(
+        IAsyncStreamReader<SyncMessage> requestStream,
+        IServerStreamWriter<SyncMessage> responseStream,
+        ServerCallContext context)
+    {
+        if (Interlocked.CompareExchange(ref _active, 1, 0) != 0)
+            throw new RpcException(new Status(StatusCode.AlreadyExists, "a sync stream is already active"));
+
+        try
+        {
+            var (duplex, readerTask) = GrpcSyncDuplex.Create(requestStream, responseStream, context.CancellationToken);
+            var session = SyncSessionFactory.Create(_db, _options, _loggerFactory);
+            await session.RunAsync(duplex, context.CancellationToken);
+            await readerTask;
+        }
+        catch (OperationCanceledException) when (context.CancellationToken.IsCancellationRequested)
+        {
+            // Client disconnect / server shutdown: the normal end of a long-lived streaming RPC.
+        }
+        catch (LocalDbSchemaMismatchException ex)
+        {
+            throw new RpcException(new Status(StatusCode.FailedPrecondition, ex.Message));
+        }
+        finally
+        {
+            Interlocked.Exchange(ref _active, 0);
+        }
+    }
+}