rpc_dart_opentelemetry 0.3.6

OpenTelemetry tracing, metrics, and logging integration for rpc_dart.

0.3.6

Observability (best-effort error sites):

• OtelRpcInterceptorBase._finish / _finishWithError: the two metrics?.recordCall(...) calls were wrapped in empty catch (_) {}, so a misconfigured meter failed silently. The exception is still swallowed (telemetry must never break the wrapped RPC call), but it is now surfaced on the active span via a new _recordMetricsFailure helper that adds a rpc.metrics.record_failed span event (log.level=debug, exception.message, exception.stacktrace). No logger is injected into this class, so the span — the diagnostic facility it owns — is the cleanest sink.
• LogControllerOtelOutput (dispose, _sweepExpired, _evictOverflow): the three best-effort span.end() calls keep their empty catch (_) {} but now carry explicit comments documenting WHY the failure is intentionally not logged: this class IS a LogOutput, so routing an OTel export failure into a logger would re-enter the same LogController that feeds this output and recurse. Each comment also notes the failure must not abort the surrounding flush/sweep/eviction.
• No control-flow change; observability only.

0.3.5

Fixes (audit):

• RpcOtelMetrics: a single instance is shared by both the server interceptor (OtelRpcInterceptor) and the client interceptor (OtelRpcClientInterceptor) through the common OtelRpcInterceptorBase.recordCall flow. The instrument names were hardcoded to rpc.server.requests / rpc.server.duration, so client-side calls were recorded under the server namespace — a violation of the OTel RPC semantic conventions (client metrics must be rpc.client.*). RpcOtelMetrics now creates both instrument sets (rpc.server.requests/rpc.server.duration and rpc.client.requests/rpc.client.duration); recordCall takes a new RpcMetricSide side parameter (default RpcMetricSide.server, backward compatible) and routes the measurement to the matching instruments. Each interceptor reports its own side via a new OtelRpcInterceptorBase.metricSide getter (server -> RpcMetricSide.server, client -> RpcMetricSide.client), mirroring the SpanKind it already uses. Added a regression test (a6_client_server_metric_namespace_test.dart) asserting a server call lands only in rpc.server.*, a client call only in rpc.client.*, and a shared instance keeps the two sides separate.

0.3.4

Refactor (no behavior change):

• OtelRpcInterceptor (server) and OtelRpcClientInterceptor (client) were ~95% identical. Extracted the shared flow into a new OtelRpcInterceptorBase (lib/src/interceptor/otel_rpc_interceptor_base.dart): it holds the tracer/metrics fields, the four intercept* methods, and the span finishing/stream-wrapping helpers (_finish, _finishWithError, _wrapWithSpan). Each subclass now implements only startSpan — the single point of difference (server extracts the W3C parent context, uses SpanKind.server, and adds rpc.trace_id; client injects the context, uses SpanKind.client, and calls updateContext). Public API, const constructors, and barrel exports are unchanged. Future fixes to the shared flow now apply once instead of twice.

0.3.3

Fixes (audit):

• LogControllerOtelOutput: the default spanTtl was 30ms, which made the periodic sweep force-end ANY log-span still doing work after 30ms — truncating normal traces (exported with a ~30ms duration, missing the final status/attributes/error, and silently dropping the real end record). The TTL is now a leak-guard, not a duration cap: the default is 5 minutes (sweep interval 30s). maxOpenSpans LRU eviction remains the primary bound. Both stay configurable. Added a regression test asserting a span legitimately open longer than the sweep interval is NOT force-ended while live and carries its real duration on its real end record.
• Stream-wrapping span end (_wrapWithSpan in both server and client interceptors): the source is listened with cancelOnError: false, so an onError is NOT terminal — a server/bidi stream may emit a non-fatal item error and then keep emitting or complete normally. Previously the span was ended (and marked errored) on the FIRST error, dropping all later messages and the real completion. The span now ends on stream TERMINATION (onDone / onCancel) exactly once; each error is recorded on the span as an exception event as it arrives, and the last error sets the final error status. Added a regression test.

0.3.2

Web / dart2js correctness:

• Verified the full web-facing surface (both interceptors, RpcOtelMetrics, RpcOtelPropagator, LogControllerOtelOutput) compiles to JS and runs on the real web target: the audit suite passes under -p chrome. No dart:io is imported; stream wrapping uses an explicit StreamController with an onCancel hook (no async* generator), so subscription cancel propagates cleanly on dart2js.
• Added test/web_smoke_test.dart — a dart2js smoke that exercises the propagator inject/extract round-trip, the status-name/error-code tables, and the Int64 nanosecond timestamp conversion. It runs green on vm, chrome, and node.
• The audit suite is now tagged @TestOn('vm || chrome'): it builds a real opentelemetry SDK tracer whose IdGenerator calls Random.secure(), which is unavailable under the node test platform (an environment limitation, not a package bug). This keeps dart test -p node test/ green.
• Documented the dart2js timestamp caveat in LogControllerOtelOutput._toInt64: DateTime.microsecondsSinceEpoch has only millisecond resolution on the web, so span timestamps round to the nearest millisecond there. Values remain valid nanosecond epochs with preserved ordering — only precision is reduced.

Metrics (#6 — OTel histogram):

• Still blocked upstream. Checked opentelemetry up to the latest published version (0.18.11); Meter exposes only createCounter (no Histogram / UpDownCounter). rpc.server.duration therefore remains a sum counter; the TODO(#6) now records the version surveyed.

0.3.1

Fixes (audit):

• The RPC span is now installed as the ambient OTel Context.current for the duration of the handler, so spans and log-spans created inside the handler are correctly parented under the RPC span (server and client interceptors).
• rpc.grpc.status_code is now emitted as the numeric semconv integer (0..16) on both spans and metrics; the human-readable name moved to the non-semconv key rpc.grpc.status.
• LogControllerOtelOutput no longer leaks un-ended spans: the open-span map is now bounded with LRU + TTL eviction (configurable maxOpenSpans, spanTtl, sweepInterval).
• Measured call duration is now recorded via the rpc.server.duration counter (was collected but discarded). TODO: switch to a histogram once the OTel API exposes one.
• Added a test suite (the package previously shipped with none).

0.3.0

• LogControllerOtelOutput — a LogOutput that mirrors every LogController span/event into OpenTelemetry. LogSpanStart opens an OTel span with the same timestamp; nested LogScope.startSpan(...) calls become child OTel spans (relies on the new LogSpanStart.parentSpanId field in rpc_dart core). LogEvents with a spanId become span.addEvent(...); standalone events emit a single-shot span. Provide rootContextProvider: () => Context.current to nest log-spans under the active RPC span.
• Note: depends on rpc_dart ≥ the release that ships LogSpanStart.parentSpanId / traceId. Bridge silently degrades to flat spans on older versions (only direct children of the root context).
• Metrics now follow OpenTelemetry RPC semantic conventions.
  • New: single counter rpc.server.requests with rpc.system, rpc.service, rpc.method, and rpc.grpc.status_code (uppercase canonical name) attributes — both success and error increments share the same counter.
  • Removed: rpc_dart.calls.total and rpc_dart.errors.total.
  • RpcOtelMetrics.recordCall now requires statusCode: and duration:. recordError was removed (status code label distinguishes the outcome).
• OtelRpcInterceptor now sets rpc.grpc.status_code as a span attribute and derives the code from RpcStatusException when an error is thrown.
• New OtelRpcClientInterceptor — client-side counterpart that creates a SpanKind.client span and injects W3C traceparent/tracestate into the outgoing RpcContext. Cross-service traces now stitch automatically.
• New rpcGrpcStatusName(code) helper exposing the canonical gRPC status names used for the rpc.grpc.status_code label.

0.2.0

• Updated to rpc_dart: ^3.0.0.
• OtelRpcInterceptor: adapted to new resilience interceptor interfaces in core.

0.1.0

• Initial release: OtelRpcInterceptor for OpenTelemetry spans with W3C trace context propagation.
• RpcOtelMetrics for RPC call metrics via OpenTelemetry.