407 lines
18 KiB
Markdown
407 lines
18 KiB
Markdown
# Go vs .NET NATS Server: Functionality Differences
|
|
|
|
> Excludes clustering/routes, gateways, leaf nodes, and JetStream.
|
|
> Generated 2026-02-22 by comparing `golang/nats-server/server/` against `src/NATS.Server/`.
|
|
|
|
---
|
|
|
|
## 1. Core Server Lifecycle
|
|
|
|
### Server Initialization
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| NKey generation (server identity) | Y | Y | Ed25519 key pair via NATS.NKeys at startup |
|
|
| System account setup | Y | Y | `$SYS` account created; no event publishing yet (stub) |
|
|
| Config file validation on startup | Y | Stub | `-c` flag parsed, `ConfigFile` stored, but no config parser |
|
|
| PID file writing | Y | Y | Written on startup, deleted on shutdown |
|
|
| Profiling HTTP endpoint (`/debug/pprof`) | Y | Stub | `ProfPort` option exists but endpoint not implemented |
|
|
| Ports file output | Y | Y | JSON ports file written to `PortsFileDir` on startup |
|
|
|
|
### Accept Loop
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| Exponential backoff on accept errors | Y | Y | .NET backs off from 10ms to 1s on repeated failures |
|
|
| Config reload lock during client creation | Y | N | Go holds `reloadMu` around `createClient` |
|
|
| Goroutine/task tracking (WaitGroup) | Y | Y | `Interlocked` counter + drain with 10s timeout on shutdown |
|
|
| Callback-based error handling | Y | N | Go uses `errFunc` callback pattern |
|
|
| Random/ephemeral port (port=0) | Y | Y | Port resolved after `Bind`+`Listen`, stored in `_options.Port` |
|
|
|
|
### Shutdown
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| Graceful shutdown with `WaitForShutdown()` | Y | Y | Idempotent CAS-guarded `ShutdownAsync()` + blocking `WaitForShutdown()` |
|
|
| Close reason tracking per connection | Y | Y | 37-value `ClosedState` enum, CAS-based first-writer-wins `MarkClosed()` |
|
|
| Lame duck mode (stop new, drain existing) | Y | Y | `LameDuckShutdownAsync()` with grace period + stagger-close with jitter |
|
|
| Wait for accept loop completion | Y | Y | `TaskCompletionSource` signaled in accept loop `finally` |
|
|
| Flush pending data before close | Y | Y | `FlushAndCloseAsync()` with best-effort flush, skip-flush for error conditions |
|
|
|
|
### Signal Handling
|
|
| Signal | Go | .NET | Notes |
|
|
|--------|:--:|:----:|-------|
|
|
| SIGINT (Ctrl+C) | Y | Y | Both handle graceful shutdown |
|
|
| SIGTERM | Y | Y | `PosixSignalRegistration` triggers `ShutdownAsync()` |
|
|
| SIGUSR1 (reopen logs) | Y | Y | SIGUSR1 handler calls ReOpenLogFile |
|
|
| SIGUSR2 (lame duck mode) | Y | Y | Triggers `LameDuckShutdownAsync()` |
|
|
| SIGHUP (config reload) | Y | Stub | Signal registered, handler logs "not yet implemented" |
|
|
| Windows Service integration | Y | N | |
|
|
|
|
---
|
|
|
|
## 2. Client / Connection Handling
|
|
|
|
### Concurrency Model
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| Separate read + write loops | Y | Y | Channel-based `RunWriteLoopAsync` with `QueueOutbound()` |
|
|
| Write coalescing / batch flush | Y | Y | Write loop drains all channel items before single `FlushAsync` |
|
|
| Dynamic buffer sizing (512B-64KB) | Y | N | .NET delegates to `System.IO.Pipelines` |
|
|
| Output buffer pooling (3-tier) | Y | N | Go pools at 512B, 4KB, 64KB |
|
|
|
|
### Connection Types
|
|
| Type | Go | .NET | Notes |
|
|
|------|:--:|:----:|-------|
|
|
| CLIENT | Y | Y | |
|
|
| ROUTER | Y | N | Excluded per scope |
|
|
| GATEWAY | Y | N | Excluded per scope |
|
|
| LEAF | Y | N | Excluded per scope |
|
|
| SYSTEM (internal) | Y | N | |
|
|
| JETSTREAM (internal) | Y | N | |
|
|
| ACCOUNT (internal) | Y | N | |
|
|
| WebSocket clients | Y | N | |
|
|
| MQTT clients | Y | N | |
|
|
|
|
### Client Features
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| Echo suppression (`echo: false`) | Y | Y | .NET checks echo in delivery path (NatsServer.cs:234,253) |
|
|
| Verbose mode (`+OK` responses) | Y | Y | Sends `+OK` after CONNECT, SUB, UNSUB, PUB when `verbose:true` |
|
|
| No-responders validation | Y | Y | CONNECT rejects `no_responders` without `headers`; 503 HMSG on no match |
|
|
| Slow consumer detection | Y | Y | Pending bytes threshold (64MB) + write deadline timeout (10s) |
|
|
| Write deadline / timeout policies | Y | Y | `WriteDeadline` option with `CancellationTokenSource.CancelAfter` on flush |
|
|
| RTT measurement | Y | Y | `_rttStartTicks`/`Rtt` property, computed on PONG receipt |
|
|
| Per-client trace mode | Y | N | |
|
|
| Detailed close reason tracking | Y | Y | 37-value `ClosedState` enum with CAS-based `MarkClosed()` |
|
|
| Connection state flags (16 flags) | Y | Y | 7-flag `ClientFlagHolder` with `Interlocked.Or`/`And` |
|
|
|
|
### Slow Consumer Handling
|
|
Go implements a sophisticated slow consumer detection system:
|
|
- Tracks `pendingBytes` per client output buffer
|
|
- If pending exceeds `maxPending`, enters stall mode (2-5ms waits)
|
|
- Total stall capped at 10ms per read cycle
|
|
- Closes with `SlowConsumerPendingBytes` or `SlowConsumerWriteDeadline`
|
|
- Sets `isSlowConsumer` flag for monitoring
|
|
|
|
.NET now implements pending bytes tracking and write deadline enforcement via `Channel<ReadOnlyMemory<byte>>`. Key differences from Go: no stall/retry mode (immediate close on threshold exceeded), write deadline via `CancellationTokenSource.CancelAfter` instead of `SetWriteDeadline`. `IsSlowConsumer` flag and server-level `SlowConsumerCount` stats are tracked for monitoring.
|
|
|
|
### Stats Tracking
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| Per-connection atomic stats | Y | Y | .NET uses `Interlocked` for stats access |
|
|
| Per-read-cycle stat batching | Y | Y | Local accumulators flushed via `Interlocked.Add` per read cycle |
|
|
| Per-account stats | Y | N | |
|
|
| Slow consumer counters | Y | Y | `SlowConsumers` and `SlowConsumerClients` incremented on detection |
|
|
|
|
---
|
|
|
|
## 3. Protocol Parsing
|
|
|
|
### Parser Architecture
|
|
| Aspect | Go | .NET |
|
|
|--------|-----|------|
|
|
| Approach | Byte-by-byte state machine (74 states) | Two-phase: line extraction + command dispatch |
|
|
| Case handling | Per-state character checks | Bit-mask lowercase normalization (`\| 0x20`) |
|
|
| Buffer strategy | Jump-ahead optimization for payloads | Direct size-based reads via Pipe |
|
|
| Split-buffer handling | argBuf accumulation with scratch buffer | State variables (`_awaitingPayload`, etc.) |
|
|
| Error model | Inline error sending + error return | Exception-based (`ProtocolViolationException`) |
|
|
| CRLF in payload | Included in message buffer | Excluded by design |
|
|
|
|
### Protocol Operations
|
|
| Operation | Go | .NET | Notes |
|
|
|-----------|:--:|:----:|-------|
|
|
| PUB | Y | Y | |
|
|
| HPUB (headers) | Y | Y | |
|
|
| SUB | Y | Y | |
|
|
| UNSUB | Y | Y | |
|
|
| CONNECT | Y | Y | |
|
|
| INFO | Y | Y | |
|
|
| PING / PONG | Y | Y | |
|
|
| MSG / HMSG | Y | Y | |
|
|
| +OK / -ERR | Y | Y | |
|
|
| RS+/RS-/RMSG (routes) | Y | N | Excluded per scope |
|
|
| A+/A- (accounts) | Y | N | Excluded per scope |
|
|
| LS+/LS-/LMSG (leaf) | Y | N | Excluded per scope |
|
|
|
|
### Protocol Parsing Gaps
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| Multi-client-type command routing | Y | N | Go checks `c.kind` to allow/reject commands |
|
|
| Protocol tracing in parser | Y | N | Go calls `traceInOp()` per operation |
|
|
| Subject mapping (input→output) | Y | N | Go transforms subjects via mapping rules |
|
|
| MIME header parsing | Y | N | .NET delegates header handling to client layer |
|
|
| Message trace event initialization | Y | N | |
|
|
|
|
### Protocol Writing
|
|
| Aspect | Go | .NET | Notes |
|
|
|--------|:--:|:----:|-------|
|
|
| INFO serialization | Once at startup | Every send | .NET re-serializes JSON each time |
|
|
| MSG/HMSG construction | Direct buffer write | String interpolation → byte encode | More allocations in .NET |
|
|
| Pre-encoded constants | Y | Y | Both pre-encode PING/PONG/OK |
|
|
|
|
---
|
|
|
|
## 4. Subscriptions & Subject Matching
|
|
|
|
### Trie Implementation
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| Basic trie with `*`/`>` wildcards | Y | Y | Core matching identical |
|
|
| Queue group support | Y | Y | |
|
|
| Result caching (1024 max) | Y | Y | Same limits |
|
|
| `plist` optimization (>256 subs) | Y | N | Go converts high-fanout nodes to array |
|
|
| Async cache sweep (background) | Y | N | .NET sweeps inline under write lock |
|
|
| Atomic generation ID for invalidation | Y | N | .NET clears cache explicitly |
|
|
| Cache eviction strategy | Random | First-N | Semantic difference minimal |
|
|
|
|
### Missing SubList Features
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| `Stats()` — comprehensive statistics | Y | N | Matches, cache hits, inserts, removes, fanout |
|
|
| `HasInterest()` — fast bool check | Y | N | |
|
|
| `NumInterest()` — fast count | Y | N | |
|
|
| `ReverseMatch()` — pattern→literal query | Y | N | |
|
|
| `RemoveBatch()` — efficient bulk removal | Y | N | |
|
|
| `All()` — enumerate all subscriptions | Y | N | |
|
|
| Notification system (interest changes) | Y | N | |
|
|
| Local/remote subscription filtering | Y | N | |
|
|
| Queue weight expansion (remote subs) | Y | N | |
|
|
| `MatchBytes()` — zero-copy byte API | Y | N | |
|
|
|
|
### Subject Validation
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| Basic validation (empty tokens, wildcards) | Y | Y | |
|
|
| Literal subject check | Y | Y | |
|
|
| UTF-8/null rune validation | Y | N | Go has `checkRunes` parameter |
|
|
| Collision detection (`SubjectsCollide`) | Y | N | |
|
|
| Token utilities (`tokenAt`, `numTokens`) | Y | N | |
|
|
| Stack-allocated token buffer | Y | N | Go uses `[32]string{}` on stack |
|
|
|
|
### Subscription Lifecycle
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| Per-account subscription limit | Y | N | |
|
|
| Auto-unsubscribe on max messages | Y | Y | .NET enforces at delivery time (NatsServer.cs:269-270) |
|
|
| Subscription routing propagation | Y | N | For clusters |
|
|
| Queue weight (`qw`) field | Y | N | For remote queue load balancing |
|
|
|
|
---
|
|
|
|
## 5. Authentication & Authorization
|
|
|
|
### Auth Mechanisms
|
|
| Mechanism | Go | .NET | Notes |
|
|
|-----------|:--:|:----:|-------|
|
|
| Username/password | Y | Y | |
|
|
| Token | Y | Y | |
|
|
| NKeys (Ed25519) | Y | Y | .NET has framework but integration is basic |
|
|
| JWT validation | Y | N | |
|
|
| Bcrypt password hashing | Y | Y | .NET supports bcrypt (`$2*` prefix) with constant-time fallback |
|
|
| TLS certificate mapping | Y | Y | X500DistinguishedName with full DN match and CN fallback |
|
|
| Custom auth interface | Y | N | |
|
|
| External auth callout | Y | N | |
|
|
| Proxy authentication | Y | N | |
|
|
| Bearer tokens | Y | N | |
|
|
| User revocation tracking | Y | N | |
|
|
|
|
### Account System
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| Per-account SubList isolation | Y | Y | |
|
|
| Multi-account user resolution | Y | N | .NET has basic account, no resolution |
|
|
| Account exports/imports | Y | N | |
|
|
| Per-account connection limits | Y | N | |
|
|
| Per-account subscription limits | Y | N | |
|
|
| Account JetStream limits | Y | N | Excluded per scope |
|
|
|
|
### Permissions
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| Publish allow list | Y | Y | |
|
|
| Subscribe allow list | Y | Y | |
|
|
| Publish deny list | Y | Partial | .NET has deny in struct but limited enforcement |
|
|
| Subscribe deny list | Y | Partial | Same |
|
|
| Message-level deny filtering | Y | N | Go filters at delivery time |
|
|
| Permission caching (128 entries) | Y | N | |
|
|
| Response permissions (reply tracking) | Y | N | Dynamic reply subject authorization |
|
|
| Permission templates (JWT) | Y | N | e.g., `{{name()}}`, `{{account-tag(...)}}` |
|
|
|
|
---
|
|
|
|
## 6. Configuration
|
|
|
|
### CLI Flags
|
|
| Flag | Go | .NET | Notes |
|
|
|------|:--:|:----:|-------|
|
|
| `-p/--port` | Y | Y | |
|
|
| `-a/--addr` | Y | Y | |
|
|
| `-n/--name` (ServerName) | Y | Y | |
|
|
| `-m/--http_port` (monitoring) | Y | Y | |
|
|
| `-c` (config file) | Y | Stub | Flag parsed, stored in `ConfigFile`, no config parser |
|
|
| `-D/-V/-DV` (debug/trace) | Y | Y | `-D` for debug, `-V`/`-T` for trace, `-DV` for both |
|
|
| `--tlscert/--tlskey/--tlscacert` | Y | Y | |
|
|
| `--tlsverify` | Y | Y | |
|
|
| `--http_base_path` | Y | Y | |
|
|
| `--https_port` | Y | Y | |
|
|
|
|
### Configuration System
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| Config file parsing | Y | N | Go has custom `conf` parser with includes |
|
|
| Hot reload (SIGHUP) | Y | N | |
|
|
| Config change detection | Y | N | Go tracks `inConfig`/`inCmdLine` origins |
|
|
| ~450 option fields | Y | ~54 | .NET covers core options only |
|
|
|
|
### Missing Options Categories
|
|
- Logging options: per-subsystem log control (file, rotation, syslog, trace/debug flags are implemented)
|
|
- Advanced limits (MaxSubs, MaxSubTokens, MaxPending, WriteDeadline)
|
|
- Tags/metadata
|
|
- OCSP configuration
|
|
- WebSocket/MQTT options
|
|
- Operator mode / account resolver
|
|
|
|
---
|
|
|
|
## 7. Monitoring
|
|
|
|
### HTTP Endpoints
|
|
| Endpoint | Go | .NET | Notes |
|
|
|----------|:--:|:----:|-------|
|
|
| `/healthz` | Y | Y | |
|
|
| `/varz` | Y | Y | |
|
|
| `/connz` | Y | Y | |
|
|
| `/` (root listing) | Y | Y | |
|
|
| `/routez` | Y | Stub | Returns empty response |
|
|
| `/gatewayz` | Y | Stub | Returns empty response |
|
|
| `/leafz` | Y | Stub | Returns empty response |
|
|
| `/subz` / `/subscriptionsz` | Y | Y | Account filtering, test subject filtering, pagination, and subscription details |
|
|
| `/accountz` | Y | Stub | Returns empty response |
|
|
| `/accstatz` | Y | Stub | Returns empty response |
|
|
| `/jsz` | Y | Stub | Returns empty response |
|
|
|
|
### Varz Response
|
|
| Field Category | Go | .NET | Notes |
|
|
|----------------|:--:|:----:|-------|
|
|
| Identity (ID, Name, Version) | Y | Y | |
|
|
| Network (Host, Port, URLs) | Y | Y | |
|
|
| Security (AuthRequired, TLS) | Y | Y | |
|
|
| Limits (MaxConn, MaxPayload) | Y | Y | |
|
|
| Timing (Start, Now, Uptime) | Y | Y | |
|
|
| Runtime (Mem, CPU, Cores) | Y | Y | |
|
|
| Connections (current, total) | Y | Y | |
|
|
| Messages (in/out msgs/bytes) | Y | Y | |
|
|
| SlowConsumer breakdown | Y | N | Go tracks per connection type |
|
|
| Cluster/Gateway/Leaf blocks | Y | N | Excluded per scope |
|
|
| JetStream block | Y | N | Excluded per scope |
|
|
| TLS cert expiry info | Y | N | |
|
|
|
|
### Connz Response
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| Filtering by CID, user, account | Y | Partial | |
|
|
| Sorting (11 options) | Y | Y | All options including ByStop, ByReason, ByRtt |
|
|
| State filtering (open/closed/all) | Y | Y | `state=open|closed|all` query parameter |
|
|
| Closed connection tracking | Y | Y | `ConcurrentQueue<ClosedClient>` capped at 10,000 entries |
|
|
| Pagination (offset, limit) | Y | Y | |
|
|
| Subscription detail mode | Y | N | |
|
|
| TLS peer certificate info | Y | N | |
|
|
| JWT/IssuerKey/Tags fields | Y | N | |
|
|
| MQTT client ID filtering | Y | N | |
|
|
| Proxy info | Y | N | |
|
|
|
|
---
|
|
|
|
## 8. TLS
|
|
|
|
### TLS Modes
|
|
| Mode | Go | .NET | Notes |
|
|
|------|:--:|:----:|-------|
|
|
| No TLS | Y | Y | |
|
|
| INFO-first (default NATS) | Y | Y | |
|
|
| TLS-first (before INFO) | Y | Y | |
|
|
| Mixed/Fallback | Y | Y | |
|
|
| TLS-required | Y | Y | |
|
|
|
|
### TLS Features
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| PEM cert/key loading | Y | Y | |
|
|
| CA chain validation | Y | Y | |
|
|
| Mutual TLS (client certs) | Y | Y | |
|
|
| Certificate pinning (SHA256 SPKI) | Y | Y | |
|
|
| TLS handshake timeout | Y | Y | |
|
|
| TLS rate limiting | Y | Y | Rate enforcement with refill; unit tests cover rate limiting and refill |
|
|
| First-byte peeking (0x16 detection) | Y | Y | |
|
|
| Cert subject→user mapping | Y | Y | X500DistinguishedName with full DN match and CN fallback |
|
|
| OCSP stapling | Y | N | |
|
|
| Min TLS version control | Y | Y | |
|
|
|
|
---
|
|
|
|
## 9. Logging
|
|
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| Structured logging | Partial | Y | .NET uses Serilog with ILogger<T> |
|
|
| File logging with rotation | Y | Y | Serilog.Sinks.File with rolling file support |
|
|
| Syslog (local and remote) | Y | Y | `--syslog` and `--remote_syslog` flags via Serilog.Sinks.SyslogMessages |
|
|
| Log reopening (SIGUSR1) | Y | Y | SIGUSR1 handler calls ReOpenLogFile |
|
|
| Trace mode (protocol-level) | Y | Y | `-V` or `-T` flag enables trace-level logging |
|
|
| Debug mode | Y | Y | `-D` flag enables debug-level logging |
|
|
| Per-subsystem log control | Y | N | |
|
|
| Color output on TTY | Y | Y | Auto-detected via `Console.IsOutputRedirected`, uses `AnsiConsoleTheme.Code` |
|
|
| Timestamp format control | Y | Y | `--logtime` and `--logtime_utc` flags |
|
|
|
|
---
|
|
|
|
## 10. Ping/Pong & Keepalive
|
|
|
|
| Feature | Go | .NET | Notes |
|
|
|---------|:--:|:----:|-------|
|
|
| Server-initiated PING | Y | Y | |
|
|
| Configurable interval | Y | Y | PingInterval option |
|
|
| Max pings out | Y | Y | MaxPingsOut option |
|
|
| Stale connection close | Y | Y | |
|
|
| RTT-based first PING delay | Y | Y | Skips PING until FirstPongSent or 2s elapsed |
|
|
| RTT tracking | Y | Y | `_rttStartTicks`/`Rtt` property, computed on PONG receipt |
|
|
| Stale connection stats | Y | Y | `StaleConnectionStats` model, exposed in `/varz` |
|
|
|
|
---
|
|
|
|
## Summary: Critical Gaps for Production Use
|
|
|
|
### Resolved Since Initial Audit
|
|
The following items from the original gap list have been implemented:
|
|
- **Slow consumer detection** — pending bytes threshold (64MB) with write deadline enforcement
|
|
- **Write coalescing / batch flush** — channel-based write loop drains all items before single flush
|
|
- **Verbose mode** — `+OK` responses for CONNECT, SUB, UNSUB, PUB when `verbose:true`
|
|
- **No-responders validation** — CONNECT rejects `no_responders` without `headers`; 503 HMSG on no match
|
|
- **File logging with rotation** — Serilog.Sinks.File with rolling file support
|
|
- **TLS certificate mapping** — X500DistinguishedName with full DN match and CN fallback
|
|
- **Protocol tracing** — `-V`/`-T` flag enables trace-level logging; `-D` for debug
|
|
|
|
### Remaining High Priority
|
|
1. **Permission deny enforcement at delivery** — deny lists checked at SUB/PUB time but not during message delivery
|
|
2. **Config file parsing** — needed for production deployment (CLI stub exists)
|
|
3. **Hot reload** — needed for zero-downtime config changes (SIGHUP stub exists)
|
|
|
|
### Remaining Lower Priority
|
|
4. **Dynamic buffer sizing** — delegated to Pipe, less optimized for long-lived connections
|
|
5. **JWT authentication** — needed for operator mode
|
|
6. **OCSP support** — certificate revocation checking
|
|
7. **Subject mapping** — input→output subject transformation
|
|
8. **Subscription statistics** — SubList has no stats collection
|
|
9. **Per-account limits** — connections, subscriptions per account
|
|
10. **Reply subject tracking** — dynamic response permissions
|
|
11. **Windows Service integration** — needed for Windows deployment
|
|
12. **Per-subsystem log control** — granular log levels per component
|