[telemetry] M2 self-telemetry surface — MeterProvider + /metrics + /healthz + /readyz + ReportStatus migration#17
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Three integration tests in cmd/tracecore time out under `go test -race ./...` while passing in isolation: - TestIntegration_ClockreceiverToStdoutexporter - TestIntegration_SIGINT - TestIntegration_DoubleSIGTERM_DoesNotHang Root cause: 1.5s scenario deadlines are too tight when the race detector and concurrent package tests compete for CPU. The polling goroutine (25ms ticker) can be stalled for hundreds of ms at a time, and the subprocess itself takes longer to print its first log line under contention. The "tracecore running" log fires in ~50-200ms under normal load; clockreceiver emits 3 metric lines in ~300ms at 100ms interval. 5s gives ~16× margin over expected timing without hiding real regressions. Memory observation 782 already fixed TestIntegration_SignalDuringBoot with a signal-retry loop; that pattern does not transfer to data-flow / log-flow waits where the only knob is the deadline. Verified `make ci` green 3 consecutive runs after the change. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Add BuildInfo to CreateSettings and MeterProvider to TelemetrySettings.
Both structs gain the trailing `_ struct{}` unkeyed-init guard so
future field additions stay non-breaking. Mirrors OTel collector
component@v1.55.0 shapes — see docs/STRATEGY.md M2 rows for
"CreateSettings shape" and "TelemetrySettings shape."
BuildInfo carries the three OTel-standard fields (Command,
Description, Version). Revision + BuildDate stay in
`internal/version`, not duplicated here.
TelemetrySettings.MeterProvider is `metric.MeterProvider` from
`go.opentelemetry.io/otel/metric`. Zero-value is nil; the runtime
will substitute `metric/noop.NewMeterProvider()` in a follow-up so
receivers never have to nil-check. Test
TestTelemetrySettings_ZeroValue_MeterProviderIsNil documents that
contract.
Existing call sites (pipelinebuilder, pipelinetest fixture) use
keyed init and stay valid. No callers in tree set BuildInfo or
MeterProvider yet; M2 work-items 10+11 wire them through Runtime
and clockreceiver respectively.
Assisted-by: Anthropic:claude-opus-4-7 [Claude Code]
Signed-off-by: Tri Lam <trilamsr@gmail.com>
Introduce `internal/telemetry` and its production `MeterProvider`: OTel SDK MeterProvider backed by a single OTel Prometheus exporter that writes to a tracecore-owned `*prometheus.Registry`. The bundled PromHandler() is the http.Handler the /metrics endpoint will mount in a follow-up. The returned struct exposes: - `Provider metric.MeterProvider`: what receivers see via TelemetrySettings.MeterProvider in subsequent work items. - `Registry *prometheus.Registry`: the scrape source. - `Shutdown(ctx)`: idempotent drain hook for the runtime's shutdown unwinder. Tests pin the receiver-author contract (Meter yields a working Int64Counter whose Add is observable via the scrape) and the operator-facing contract (HEAD requests return 200 like GET, so k8s probes that prefer HEAD don't break). The idempotency contract on Shutdown matches `Component.Shutdown` per the runtime's documented invariant. Coverage 76.9% (floor 70%). The OTel Prometheus exporter is at v0.65.x (pre-1.0) — API churn is wrapped behind NewMeterProvider so future bumps touch one file, per the Loop-2 scrutiny verdict on "OTel Prom exporter API churn" risk. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
NewReceiver(id, mp) returns a Receiver backed by five OTel metric
instruments registered against the passed-in MeterProvider:
- tracecore.receiver.errors_total (Int64Counter, attr: kind,
component_id) — IncError.
- tracecore.receiver.emissions_total (Int64Counter, attr:
component_id) — IncEmissions, with the contract's silent-discard
of negatives.
- tracecore.receiver.collection_latency_seconds (Float64Histogram,
attr: component_id) — ObserveLatency in seconds.
- tracecore.receiver.degraded_seconds_total (Float64Observable
Counter, attr: component_id) — derived from SetDegraded timing.
An observable callback reports cumulative time degraded INCLUDING
the currently-open interval, so scrapes always see fresh data
even if SetDegraded(false) is never called.
- tracecore.receiver.last_activity_unix_seconds (Int64Observable
Gauge, attr: component_id) — MarkActivity timestamp.
component_id ("kind/instance" from pipeline.ID) is attached at
construction time via attribute.NewSet and shared across emissions;
no per-call allocation cost.
The observable-counter trick for degraded_seconds_total side-steps
the gotcha of "synchronous counter only flushes on transition" —
if a receiver never recovers, the counter still advances at every
scrape, which is what operators alerting on `rate(... > 0)` expect.
Atomic pointer for degradedAt + atomic uint64 for accumulated
nanoseconds keep the observable callback lock-free. SetDegraded
serializes via a small mutex to prevent double-flushing.
NilMeterProvider returns ErrNilMeterProvider rather than panicking;
the runtime is responsible for substituting noop.NewMeterProvider().
Coverage 88.6% (floor 70%).
Assisted-by: Anthropic:claude-opus-4-7 [Claude Code]
Signed-off-by: Tri Lam <trilamsr@gmail.com>
Add `telemetry.Server` that mounts all three operator-facing endpoints on a single ServeMux behind one listener. Single-listener design keeps the attack-surface footprint minimal (one port for ops to firewall, one TLS terminator to configure) and avoids the "/healthz on a different port than /metrics" footgun. Surfaces: - /metrics — promhttp handler over the OTel-fed registry from WI2. - /healthz — 200 unless shutting down; 503 once Shutdown begins. - /readyz — 200 only when the optional ReadyFn predicate returns true (and not shutting down). 503 otherwise. The runtime wires ReadyFn to its "every component Start returned" check in a follow-up; without it, /readyz behaves like /healthz. Lifecycle: - Start(ctx) binds the listener synchronously so a port-conflict error surfaces immediately, then spawns Serve in a goroutine. - Shutdown(ctx) flips the shuttingDown atomic (handlers start returning 503), calls http.Server.Shutdown bounded by ShutdownBudget (800ms — leaves headroom in the PRINCIPLES §1 1s budget), then waits for Serve to return. - Both Start and Shutdown are idempotent: double-Start returns an error; double-Shutdown is a no-op; Shutdown without Start is a no-op. Matches Component.Shutdown's documented contract. Config validation rejects empty Listen, nil MeterProvider, paths missing the leading "/" — operator-facing errors point at the specific YAML field per STYLE-errors. ReadHeaderTimeout 5s caps the slow-Loris vector. No further hardening in M2; production deploys front this with a reverse proxy. Coverage 73.5% (floor 70%). Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Add `telemetry: { enabled, listen, paths }` to internal/config.
Default OFF so production binaries don't open a port until
operators opt in (the security-conscious-operator persona's
tiebreaker per docs/loops/m2-research.md Pass 3).
Defaults when enabled:
listen: "localhost:8888" (localhost-only is safer than
:8888; operators flip to ":8888"
on the first multi-node scrape)
paths:
metrics: /metrics
healthz: /healthz
readyz: /readyz
The applyDefaults / validate split keeps disabled blocks untouched,
so operators may keep a fully-spelled production template
commented or with `enabled: false` without tripping validation.
Validation errors name the offending YAML field (e.g.,
"telemetry.paths.metrics: must be an absolute path starting with
'/'") per STYLE-errors.
Coverage 93.1% (floor 70%).
Assisted-by: Anthropic:claude-opus-4-7 [Claude Code]
Signed-off-by: Tri Lam <trilamsr@gmail.com>
Move status reporting from `Host.ReportStatus(ev)` method to free function `componentstatus.ReportStatus(host, ev)` per docs/STRATEGY.md M2 row for "Host.ReportStatus." Aligns with OTel collector v0.152's componentstatus package without pulling the external dep. Changes: - New `internal/componentstatus` package: `ReportStatus(host, ev)` free fn + optional `StatusReporter` interface (host opts in). - `pipeline.Host` interface loses the `ReportStatus` method; it's now just `GetExtensions()` (mirrors OTel `component.Host` shape at v1.55.0). - `pipeline.noopHost` loses its ReportStatus method. - `pipelinetest.Host.ReportStatus` renamed to `ReportComponentStatus` so it implements the optional interface; tests call the free fn. - runtime_test asserts the noop-host path is silent-discard, not a panic — matches OTel's documented contract for hosts that don't implement StatusReporter. Receivers calling ReportStatus today (none in tree yet) port with a one-line edit: - host.ReportStatus(ev) + componentstatus.ReportStatus(host, ev) 100% coverage on the new package; existing tests still green. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Add functional options `WithMeterProvider` + `WithBuildInfo` to
`pipelinebuilder.BuildPipelines`. Both flow through into every
component's `pipeline.CreateSettings.{BuildInfo, Telemetry.MeterProvider}`.
Default MeterProvider is `noop.NewMeterProvider()` so receivers
calling `telSet.MeterProvider.Meter(...)` never hit a nil pointer
even when the caller skips the option (matches the
TestTelemetrySettings_ZeroValue_MeterProviderIsNil contract: the
RUNTIME is responsible for substitution, not the receiver).
Default BuildInfo is the zero value (acceptable for tests; the binary
populates it from `internal/version`).
The options pattern keeps the four-positional-arg signature
backward-compatible across the ~10 existing call sites in
cmd/tracecore tests; only sites that need M2's wiring opt in.
Tests pin both contracts (default-noop, flow-through for both
options).
Assisted-by: Anthropic:claude-opus-4-7 [Claude Code]
Signed-off-by: Tri Lam <trilamsr@gmail.com>
Construct the real selftelemetry.Receiver in newReceiver() using
set.Telemetry.MeterProvider and set.ID, and call it on every tick:
- ObserveLatency: wraps the ConsumeMetrics push.
- IncEmissions(1): on success.
- IncError("downstream"): on push failure.
- MarkActivity: on success (mirrors emissions for now;
receivers with separate "collected vs emitted" semantics may
diverge).
The receiver retains a `selftelemetry.Receiver` field (never nil)
and falls back to the noop impl if either MeterProvider is missing
OR NewReceiver fails. The fallback path logs a warning via the
component-scoped logger so an operator notices in stderr while the
hot path stays branch-free.
Coverage 83.1% (clockreceiver), test suite still green. No
behavior change to the metric data path; only the self-telemetry
side channel.
This is the canonical wiring pattern for M8 (DCGM) and M9
(kernelevents) — those receivers should copy the newReceiver()
shape verbatim. Documented in docs/agents/RECEIVER-PATTERNS.md in
a follow-up.
Assisted-by: Anthropic:claude-opus-4-7 [Claude Code]
Signed-off-by: Tri Lam <trilamsr@gmail.com>
cmd/tracecore.runCollect now plumbs the M2 telemetry surface when the operator enables it in config: 1. Build BuildInfo from internal/version. 2. If cfg.Telemetry.Enabled: construct telemetry.MeterProvider + telemetry.Server. Start the Server FIRST so /healthz + /readyz are observable from the moment the binary commits to running. 3. Pass MeterProvider + BuildInfo into pipelinebuilder.BuildPipelines via the WI10a options. 4. After Runtime.Start succeeds, flip the `ready` atomic so /readyz transitions 503 → 200. ReadyFn closes over `ready.Load`. 5. On signal: flip `ready` to false (scrapers stop sending traffic), shut down Runtime, then telemetry server, then MeterProvider in that order — connections close before metric exports drain. Integration test pins the contract end-to-end: - TestIntegration_TelemetrySurface_EndToEnd: boots with telemetry enabled, polls /healthz + /readyz to 200, scrapes /metrics and asserts the three clockreceiver self-metric families appear (emissions_total, last_activity_unix_seconds, collection_latency_seconds), SIGTERMs cleanly. - TestIntegration_TelemetryDisabled_NoListener: confirms the default-off contract — a config without `telemetry:` does NOT bind any port; localhost:8888 refuses connections. Bump go directive 1.26.2 → 1.26.3 to pull in the fix for GO-2026-4971 (Windows-only net.Dial NUL-byte panic). Required because govulncheck traces our new net.Listen call site to the vulnerable stdlib version; without the bump CI fails on darwin/linux even though the bug can't trigger on those platforms. Coverage: cmd/tracecore at 68.6% informational; new components + selftelemetry + telemetry stay above their 70% floors. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Land the M2 documentation set: - RFC-0006: spec for the self-telemetry surface (producer + operator surfaces, lifecycle, divergences, risks, acceptance tests). - internal/telemetry/README.md: operator quickstart — config, endpoint contracts, self-metric taxonomy, backend compatibility, failure modes, receiver-author wiring snippet. - CHANGELOG.md [Unreleased] / Added: M2 bullet covering the surface, the wire-up, and the three STRATEGY divergence rows closed. - MILESTONES.md M2: marked delivered; explicit Carry-forward bullets for pprof, O2-SLO exporter/queue metrics, OTLP push reader, MetricsLevel knob, bucket tuning, per-role CreateSettings split, TracerProvider field. Acceptance criteria ticked vs deferred per the loop's decision. - STRATEGY.md divergence table: three M2 rows move from "open" to "done"; added three new "permanent" rows for the localhost-only default, the tracecore.* metric namespace, and the in-tree componentstatus package. - docs/FAILURE-MODES.md: new "Self-telemetry surface (M2)" section with 11 rows (default-off, port-conflict, validate errors, /healthz + /readyz state transitions, shutdown budgets, fd-leak guard). - docs/FOLLOWUPS.md: "Considered and explicitly skipped (M2)" section — MetricsLevel, Candidate B (Prom-direct), Candidate C (hybrid), per-role split, TracerProvider — with reasons so the decisions don't get re-suggested. - docs/agents/RECEIVER-PATTERNS.md: the canonical six-line self-telemetry wiring pattern M8/M9 should copy. - docs/agents/REVIEWER-CONTEXT.md: divergences table updated to reflect M2 closures + the new permanent rows. `make ci` clean: 31 doc-check references verified; coverage above floors; no vulnerabilities. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Two doc updates that didn't make the prior docs commit. Add the M2 [Unreleased] / Added bullet to CHANGELOG (covers the surface, the wire-up, and the three STRATEGY divergence rows closed) and the canonical self-telemetry wiring pattern under "Active patterns" in RECEIVER-PATTERNS.md (M8/M9 should copy the six-line constructor pattern verbatim). Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Address overwhelming-success criterion 10 by emitting the three M2
SLO gauges with the exact names the criterion lists:
- tracecore.exporter.failure_rate — driven by real exporter signal
- tracecore.queue.depth_ratio — 0 (M2 carry-forward; needs queue mechanism)
- tracecore.component.restart_count_per_hour — 0 (M2 carry-forward; needs restart mechanism)
Producer side:
- New `selftelemetry.Exporter` interface (`IncCallSuccess`,
`IncCallFailure(kind)`) parallel to `Receiver`. Real impl in
`selftelemetry.NewExporter(id, mp)` emits
`tracecore.exporter.calls_total{result,kind,component_id}` and
satisfies `FailureRateReader` (SuccessCount/FailureCount) so the
SLO layer can aggregate.
- `noopExporter` matches the noop pattern from Receiver.
- `stdoutexporter` wired: `IncCallSuccess()` on success path,
`IncCallFailure("marshal" | "io")` on the two failure paths.
Exposes `SelfExporter()` so the runtime can pluck the
FailureRateReader.
Operator side:
- `internal/telemetry.RegisterSLOMetrics(mp, src)` registers the
three Float64ObservableGauges with the exact criterion names.
- `internal/telemetry.SLOSource` is the values-feeder interface.
`AggregateSLOSource` reads from every registered exporter via
`ExporterRegistry`. `ZeroSLOSource` is the no-signal stub for
tests + `tracecore validate`.
- Div-by-zero guard: total=0 returns 0 rather than NaN, so
Prometheus alerts firing on `> 0` don't get poisoned.
Wire-up in `cmd/tracecore`:
- After BuildPipelines returns, walk pipelines.Exporters, collect
every `SelfExporter()` that satisfies FailureRateReader, hand to
`AggregateSLOSource`, call `RegisterSLOMetrics`.
Tests:
- `internal/telemetry/slo_test.go`: all-three-names-appear,
failure-rate math, no-calls-is-zero (div-by-zero guard),
queue+restart carry-forward zero, nil-arg rejection, end-to-end
failure_rate from a registered exporter.
- `internal/selftelemetry/exporter_test.go`: success+failure
counter labels, FailureRateReader satisfaction, nil-provider
rejection, noop discard.
- Integration test in `cmd/tracecore/integration_telemetry_test.go`
extended to assert all three SLO names + the underlying
`tracecore_exporter_calls_total` counter appear in the scrape.
Coverage: telemetry 78.2%, selftelemetry 89.8%, stdoutexporter
72.2%. All above floors. make ci green.
Assisted-by: Anthropic:claude-opus-4-7 [Claude Code]
Signed-off-by: Tri Lam <trilamsr@gmail.com>
Update MILESTONES.md M2 row to reflect the SLO observable gauges now ship; CHANGELOG entry documents the three named gauges + the raw exporter.calls_total counter; internal/telemetry/README.md gains the exporter-side and SLO-gauge taxonomy. Carry-forwards updated: queue + restart mechanisms now point at the gauges that are already registered + reporting 0 until the underlying mechanisms land, so operators can write Prometheus alerts against the names today. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Add an assertion for `tracecore_receiver_degraded_seconds_total` to the end-to-end integration test. Observable counters emit on every scrape via their callback, so the value is 0 (clockreceiver never calls SetDegraded), but the metric name + zero data point surface — bringing integration coverage to 4 of the 5 receiver-side methods. The 5th, IncError → `tracecore_receiver_errors_total`, only surfaces on actual downstream failure. clockreceiver → stdoutexporter doesn't fail under normal operation, so that path is unit-tested (TestReceiver_IncError) rather than integration-tested. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Two real bugs found on self-review of the M2 PR: 1. Server.Start that fails AFTER the started.CAS leaves started=true but no Serve goroutine spawned. Any subsequent Shutdown call (e.g., from cmd/tracecore's failure-unwinder) blocks on <-s.doneCh forever because the goroutine never closes it. Fix: close doneCh in the error path. Regression test TestServer_ShutdownAfterFailedStart_DoesNotHang reproduces by pre-binding a port to force EADDRINUSE. 2. Server.Start's goroutine swallowed http.Server.Serve errors silently (`_ = err`). A listener crash mid-run produced no tracecore log entry; operators were left wondering why /metrics stopped responding. Fix: add Logger field to ServerConfig (defaults to discard, cmd/tracecore wires the runtime logger). Log non-ErrServerClosed errors at slog.Error. cmd/tracecore now passes its logger into ServerConfig. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
The previous AggregateSLOSource computed lifetime cumulative failure ratio. After a single failure on call #1, the gauge stayed > 0 forever — useless for SLO alerting that targets a recent window. Replace with a sliding-window source: maintain a ring of timestamped (success, failure) snapshots; on each scrape, find the latest sample ≥ window-old as the anchor and compute (Δfailure / Δtotal) since. Returns 0 while warming up (no anchor yet) and on zero in-window calls. DefaultSLOWindow is 60s — matches typical k8s probe cadence. API change: AggregateSLOSource gains state and a constructor (NewAggregateSLOSource). cmd/tracecore updated; tests rewritten to exercise the windowing semantics: - TestAggregateSLOSource_WindowedRate: signal in window appears as the expected rate; subsequent signal at the same in-window ratio stays at the same rate. - TestAggregateSLOSource_WindowedRate_LifetimeRatioNotReflected: the bug-driving case — a long-ago single failure doesn't pin the gauge above 0 once it rolls out of the window. Ring buffer is pruned to 2× window of samples per scrape so memory stays bounded under fast scrape cadence. Coverage: internal/telemetry up to 83.6%. make ci clean. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Three closures from the self-review: - DF2 falsifier (Loop 1): TestReceiver_ConcurrentRegistration_SameNames spawns 8 receivers in parallel against the same MeterProvider, all register the same instrument names, all emit successfully. Pins the OTel SDK's idempotent-registration contract, which is the M8/M9 case (multiple receivers starting concurrently). - End-to-end failure_rate signal: TestRegisterSLOMetrics_RealExporter_EndToEnd uses the REAL selftelemetry.NewExporter (not the fakeFailureReader stub) to drive the full chain: real exporter → AggregateSLOSource → SLO gauge → /metrics scrape. Pins both the wiring and the math in one test. - stdoutexporter empty-payload now counts as success. Previously the early return left the calls_total counter under-counting actual ConsumeMetrics invocations; operators expecting "calls = consumes received" saw a discrepancy. The contract was fulfilled (zero work, no error), so it's a success. - BuildInfo.Description corrected from "self-hosted telemetry collector" (inaccurate copy) to "observability collector for GPU clusters" — describes what tracecore actually is. Coverage telemetry 83.6%, selftelemetry 89.8%, stdoutexporter 72.2% (unchanged). make ci clean. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
CHANGELOG, RFC-0006 risk table, and internal/telemetry/README.md updated to describe: - failure_rate is a rolling 60s window (not lifetime cumulative). - raw tracecore.exporter.calls_total counter is the primitive for custom-window PromQL. - Three risks added to the RFC table for the bugs caught on self-review (Start-after-CAS hang, Serve error swallow, lifetime ratio misleading). Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Six self-review closures bringing M2 toward A+:
- collectFailureRateReaders dedups by FailureRateReader pointer
identity. An exporter shared across pipelines (legal today —
e.g., same stdoutexporter from metrics/primary + metrics/secondary)
was being double-counted in the failure_rate calculation.
Test: TestCollectFailureRateReaders_Dedup pins via pointer-shared
exporter across two pipelines.
- internal/telemetry.RegisterBuildInfo emits tracecore.build.info as
an Int64ObservableGauge with value 1 and command/version/revision
labels. Mirrors otelcol_build_info / prometheus_build_info
convention; operators join against it in PromQL. cmd/tracecore
wires it after MeterProvider construction.
- docs/examples/with-telemetry.yaml — operator-runnable example
showing the telemetry block. internal/telemetry/README.md points
here so operators see the full config shape, not just the snippet.
- TestServer_LogsServeErrorOnUncleanExit upgraded from negative-
only (clean shutdown doesn't log) to positive (fault-injection
listener returns error from Accept; assertion: the Logger sees
"Serve exited with error" + the fault string). Adds
StartWithListenerForTest export for the injection path.
- TestServer_HealthzStays200WhileDraining pins the drain-window
policy: ready=false but Server.Shutdown not yet started →
/healthz=200, /readyz=503. k8s wants exactly this signal during
graceful drain.
- TestIntegration_ErrorsTotal_SurfacesOnDownstreamFailure pins
criterion 8's last unverified case: clockreceiver →
failingSink (always errors) → errors_total{kind="downstream"}
surfaces in the scrape. The full producer chain runs (real
MeterProvider, real TelemetrySettings, real selftelemetry.NewReceiver
inside clockreceiver) without a subprocess.
Coverage: telemetry 85.8%, selftelemetry 89.8%, clockreceiver
92.3%, componentstatus 100%. make ci clean.
Assisted-by: Anthropic:claude-opus-4-7 [Claude Code]
Signed-off-by: Tri Lam <trilamsr@gmail.com>
Apply 2 blockers + 6 strong findings from the Pass-1 reviewer agents:
Reviewer A (correctness, Explore):
- BLOCKER: AggregateSLOSource held a pointer into s.samples then
append'd, risking a use-after-realloc footgun. Capture by value
instead. (slo.go)
Reviewer B (UX, general-purpose):
- BLOCKER: tracecore_build_info was emitted but undocumented in
the operator-facing README. Added a "Build identity" section
with labels, the canonical join PromQL, and the rationale.
- STRONG: tracecore.exporter.failure_rate description hid the
rolling-60s-window semantics — auto-generated dashboards would
treat it as lifetime ratio. Description now states the window
explicitly + points at the raw counter for custom windows.
- STRONG: selftelemetry used per-instance Meter scope names
(`Meter(id.String())`), stamping `otel_scope_name="kind/instance"`
on every series and doubling cardinality versus the
`component_id` label we already carry. Switched to the
package-stable
`github.com/tracecoreai/tracecore/internal/selftelemetry` scope.
- STRONG: http.Server had only ReadHeaderTimeout configured —
slowloris attack surface when operators flip listen to ":8888"
per docs. Added ReadTimeout, WriteTimeout, IdleTimeout,
MaxHeaderBytes with conservative defaults.
- STRONG: ReadyFn=nil defaulted to 200, contradicting RFC-0006's
"before [ready flips true] /readyz returns 503". Flipped to
default-503 ("not ready until proven ready"); production always
passes a real predicate so behavior is unchanged in tracecore
itself.
- STRONG: RFC-0006 promised goleak as the listener-fd-leak
mitigation; the test never shipped. Added
TestServer_RepeatedStartShutdown_NoLeaks — 10 cycles, asserts
goleak.Find sees no leak.
- STRONG: docs/examples/with-telemetry.yaml comment said "uncomment
+ set enabled: true" while the file shipped with enabled: true
already. Rewrote the comment so it describes shipped state
honestly.
NITS folded in:
- /healthz + /readyz handlers set explicit `Content-Type: text/plain;
charset=utf-8` so a future code-path that writes the header before
the body doesn't trip on a sniffed Content-Type.
- Carry-forward gauge descriptions reworded — dropped internal
"M2 carry-forward" vocabulary; operators see "always 0 until a
future release" instead.
Coverage: internal/telemetry up to 86.1%; others unchanged. make ci
clean.
Assisted-by: Anthropic:claude-opus-4-7 [Claude Code]
Signed-off-by: Tri Lam <trilamsr@gmail.com>
Apply 8 strong findings from Pass-2 reviewers (security + docs): Reviewer C (security, general-purpose): - STRONG: HTTP handler panic could crash the binary (PRINCIPLES §1 "never crash the workload" is load-bearing for self-telemetry). Added recoverHandler middleware wrapping the ServeMux: any panic (from promhttp, OTel observable callbacks, or future bugs) logs via cfg.Logger and returns 500. Test TestServer_RecoversFromHandlerPanic forces a panic via ReadyFn. - STRONG: RegisterBuildInfo accepted arbitrary label keys. Invalid Prom names (hyphens, dots, leading digits, empty) get silently mangled to `_` by the OTel→Prom translator, causing hidden collisions. Now validates against [a-zA-Z_][a-zA-Z0-9_]* with a clear error. Test TestRegisterBuildInfo_RejectsBadLabelKey. - STRONG: MaxHeaderBytes was 1 MiB — way too generous for an endpoint where legitimate requests are sub-1KB GETs. Shrunk to 8 KiB; reduces resource burn from slow-header attacks while Prom + curl never approach this. - STRONG: /healthz + /readyz responses lacked Cache-Control: no-store. A misconfigured proxy could cache 200 after the pod flipped to 503, defeating k8s readiness gating. Added the header to both handlers. - STRONG: SLO sample ring's `samples[drop:]` reslice kept the old backing array alive across resizes, defeating the memory bound. Now copies into a fresh slice. Added defense-in-depth cap (maxSamples=4096 ≈ 160KiB) for misconfigured 1ms scrape cadence. - Security posture section added to internal/telemetry/README.md explicitly stating "plaintext HTTP; non-loopback binds REQUIRE a reverse proxy with TLS + auth — tracecore ships no TLS in M2." Reviewer D (docs, Explore): - STRONG: RFC-0006 acceptance row said "three clockreceiver self-metrics visible"; the actual test asserts four (and a separate test covers the 5th, errors_total). Updated row. - STRONG: RECEIVER-PATTERNS.md "Self-telemetry wiring" listed call ordering that didn't match clockreceiver.emit. Replaced with the literal six-line snippet from clockreceiver, with a note that ObserveLatency intentionally covers failures too. Also linked the example YAML. - Integration test asserts tracecore_build_info carries the three canonical labels in the scrape (values empty under `go test` — -ldflags only populate in production builds). - cmd/tracecore.collect now passes telemetry.DefaultSLOWindow explicitly rather than relying on the constructor's zero-coercion (Pass-2 nit). Coverage telemetry 85.1%, selftelemetry 89.8%, componentstatus 100%. make ci clean. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Apply 6 of the 10 findings from Pass-3 reviewer F (M8/M9 author
perspective). Reviewer E identified 0 blockers for 1.0-stable.
HIGH priority (real M8/M9 unblockers):
- Resource attrs were empty. pipelinebuilder now populates
pcommon.Resource with host.name (os.Hostname), service.name +
service.version (from BuildInfo), service.instance.id. M8/M9
receivers reading `set.Telemetry.Resource` get canonical OTel
semconv attributes rather than a bare empty Resource that
would ship as label-less pdata to operators.
- Canonical `kind` constants published in
`internal/selftelemetry/interface.go`: KindConnect, KindParse,
KindDownstream, KindEnumerate, KindRead, KindCardinality,
KindPanic, KindInit. M8 and M9 were already diverging silently
(M8 uses "init"/"watch"/"mig"/"consume"; M9 uses
"journalctl_crash"/"kmsg_oversized"). Cross-receiver Prom
dashboards on `{kind=…}` now have a stable canonical set.
MEDIUM priority (operator-alert correctness):
- `last_activity_unix_seconds` was 0 until first MarkActivity,
meaning alerts on `time() - last_activity > 60` fired during
receiver boot. NewReceiver now seeds activityUnix to
construction time — gauge reports "alive but no activity yet"
rather than 1970-01-01.
- `ObserveLatency` godoc now states the convention explicitly:
observed for both successes AND failures, with splitting
deferred to a future ergonomics pass. M9 was diverging from
clockreceiver here; the doc now anchors the contract.
- `SetDegraded` godoc requires receivers booting already-degraded
(e.g. NVML init fails at Start) to call SetDegraded(true)
explicitly so degraded_seconds_total begins ticking. Without
this, alerts on `> 0` miss boot-time stuck-degraded receivers
until first recovery.
LOW priority:
- RECEIVER-PATTERNS.md pattern doc wording clarified: "inside
the receiver's newReceiver (the function the factory's
CreateMetrics calls)" rather than the ambiguous "factory's
create path."
DEFERRED (out of scope for M2):
- Test-injection seam helper (would add scope; M8/M9 already
ship their own Option pattern).
- selftelemetry init-failed metric (silent fallback to noop is
acceptable; revisit if operators see it).
- ReportStatus available at construct time (Host arrives at Start;
document at next ergonomics pass).
- Processor producer interface (post-M2; no in-tree processor yet).
Coverage: pipelinebuilder 74.7% → 76.2%; selftelemetry 89.8% → 90.0%.
make ci clean.
Assisted-by: Anthropic:claude-opus-4-7 [Claude Code]
Signed-off-by: Tri Lam <trilamsr@gmail.com>
The three reviewer passes produced ~30+ findings; ~20 were addressed in code (commits c685f43, 0fa17a6, 628c5ea), but the remaining items were not written down. Add an "M2 Loop 4 reviewer deferrals" section to FOLLOWUPS.md cataloging every reviewer-raised item that was intentionally NOT shipped in the M2 PR. Grouped by category, each with rationale + revisit condition: - Hardening / observability of the surface itself: * scrape_panics_total counter (log path suffices today) * serve_exited{reason} counter (log path suffices today) * selftelemetry.init_errors_total (silent noop OK until reported) - Cardinality + cost guards: * Runtime cap on kind cardinality (doc-only enforcement today) * Histogram bucket tuning (defer until real-receiver data) - API ergonomics (third-caller defer): * selftelemetry.NewRecordingReceiver(t) test helper * selftelemetry.Processor producer interface * Per-exporter failure_rate{component_id} series * Live ExporterRegistry (factory func vs snapshot) * Unexporting AggregateSLOSource - Edge cases worth a test someday: * Tighter Server path validation (url.Parse) * uint64 underflow guard in AggregateSLOSource * Server.Shutdown ctx semantics under expired contexts * SetDegraded ↔ observable-callback mutex consistency - Documentation polish: * Datadog backend compatibility claim (unverified) This closes the "did you document all deferrals" gap I left after the reviewer passes. Now every floating item has either (a) a commit closing it or (b) a documented rationale + revisit. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Close concrete gaps from the self-rating "B+ effort, A- artifact":
1. CRITERION 13 VERIFIED. Actually rebased M8/M9 onto
feat/m2-self-telemetry. Both branches conflict ONLY in additive
doc files (CHANGELOG, RECEIVER-PATTERNS, FAILURE-MODES — where
both M2 and M8/M9 added new entries to the same sections). ZERO
Go code conflicts. The criterion's "no changes beyond the rebase"
promise is met for Go; doc merges are one-minute mechanical.
2. EXAMPLE CONFIG IS NOW CI-GATED.
TestIntegration_ExampleConfigValidates runs `tracecore validate`
against docs/examples/with-telemetry.yaml. Doc rot (schema drift
vs the example) now breaks CI rather than shipping to operators.
3. THREE SAFETY ITEMS FROM FOLLOWUPS:
- uint64 underflow guard in AggregateSLOSource: if a future
restart-mechanism non-monotonically resets exporter counters,
`failure - anchor.failure` would wrap to ~2^64 and pin the
gauge at garbage. Guarded with `if failure < anchor.failure
{ return 0 }`.
- Tighter path validation in telemetry.Server: rejects paths
with whitespace, control bytes, query strings, fragments —
surfaces the operator-actionable error rather than letting
http.ServeMux panic at registration.
- tracecore.selftelemetry.init_errors_total counter: the
silent-noop-fallback path in clockreceiver/stdoutexporter
factories now ticks an Int64Counter so operators alerting on
`> 0` see when a component is silently running with the noop.
RecordInitError takes ctx (linted via contextcheck), errors
from the meta-counter itself are swallowed so the meta-path
can't crash callers. Test pins all three labels surface.
4. SLO CALLBACK PERFORMANCE BENCHMARKED.
BenchmarkAggregateSLOSource_ExporterFailureRate_{1,10,100}Readers
at internal/telemetry/slo_bench_test.go. Apple M4 Pro results:
3.89µs (1 reader), 3.98µs (10), 4.63µs (100), 0 allocs/op
steady-state. Operators scraping at 15s pay <5µs CPU per scrape
even at 100 exporters. PRINCIPLES §1 ("self-telemetry must never
spike CPU") demonstrably honored. Numbers documented in README
"Performance" section.
5. DATADOG BACKEND CLAIM HEDGED. README compatibility matrix now
distinguishes "verified" (Prometheus + Grafana, CI-tested),
"verified-by-protocol" (Mimir/Thanos/VictoriaMetrics, Prom-spec
compatible), and "unverified" (Datadog Agent — the integration
should work but tracecore has not been end-to-end-tested against
a real Agent). Honest claims only.
Coverage: selftelemetry 89.8% → 89.6% (RecordInitError covered);
telemetry 85.1% → 83.7% (new validateMountPath + perf benchmark code
not counted as covered statements). All above floors. make ci clean.
Per-exporter failure_rate label intentionally NOT shipped — Pass-2
reviewer C explicitly deferred it pending multi-exporter deployment
demand, and FOLLOWUPS.md (commit 6b0af2d) records the decision.
Reversing the deferral mid-PR would be flip-flopping, not A+.
Assisted-by: Anthropic:claude-opus-4-7 [Claude Code]
Signed-off-by: Tri Lam <trilamsr@gmail.com>
Address self-review items #5 (pkg-name confusion), #12 (MILESTONES glyph), #16+#17 (commit/scope discipline), #18 (telemetry pkg architecture intent), #19 (Resource auto-pop) — all doc-only. internal/telemetry/doc.go + internal/selftelemetry/doc.go: explicit "where do I add code" guidance with the conceptual split (process- level SURFACE vs per-component PRODUCER CONTRACT). Includes the architecture intent for future milestones — when tracing lands the TracerProvider goes in `telemetry`, signal-direction-driven split (consumer/producer) rather than modality-driven (metrics/traces). selftelemetry/doc.go also pins the cardinality contract explicitly (every label value must be low-cardinality; canonical Kind* constants exist for that purpose) and the Resource auto-population contract. MILESTONES.md: new ☒ glyph for "policy-declined, not deferred." Applied to the /readyz SLO-threshold criterion — RFC-0006 explicitly chose degraded ≠ not-ready, that's a policy, not a missing feature. FOLLOWUPS.md: new "M2 process lessons" section captures three honest process gaps from this milestone for the next loop's prompt: - Scope-creep (Go-bump + CI-fix-deadlines shipped under [telemetry]) - Commit history discipline (25 commits incl. 13 review-fixes) - Self-assessment optimism caught by gates four separate times Lessons → next-milestone-prompt input, not corrective action for M2 (retroactive split blocked by no-force-push rule). Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Address items #9 (--version OTel SDK), #13 (Example_* tests), #14 (Kind constant coverage + helper), #15 (shutdown error logging). Also tactical: extract initTelemetryStack from runCollect so the silent-shutdown-error fix didn't push cyclomatic complexity past 15. - internal/version: Build gains OTelSDKMetric + OTelPromExporter fields, populated from debug.ReadBuildInfo. Surfaces in --version output as `otel-sdk-metric=vX.Y.Z, otel-prom-exporter=vA.B.C`. Operators debugging OTel-side bugs see which SDK actually shipped without grep'ing go.mod. - internal/selftelemetry: new CanonicalKinds() returning the Kind* constant set and IsCanonicalKind(s) helper. Test pins the set + asserts clockreceiver's KindDownstream is canonical. Future receivers (M8/M9) plug in the same test pattern; eventual lint enforcement is documented in FOLLOWUPS. - internal/selftelemetry/example_test.go: ExampleNewReceiver + ExampleNewExporter render in pkg.go.dev for M8/M9 authors and compile-check the 6-line wiring pattern every CI run. The RECEIVER-PATTERNS.md snippet can no longer drift from a working example without breaking this test. - cmd/tracecore.runCollect: previously swallowed mp.Shutdown errors in the failure-unwinder paths with `_ = mp.Shutdown(ctx)`. Now logs at Warn level so a real drain failure surfaces. Extracted the telemetry-init block into initTelemetryStack helper to keep runCollect's cyclomatic complexity under the gocyclo 15 ceiling (the helper's own error-handling carries the rest of the cleanup branches). make ci clean. Coverage unchanged on most pkgs; selftelemetry up to 91.0% via the new IsCanonicalKind test. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Address item #6: ServerConfig had 7 exported fields with the three path knobs (MetricsPath, HealthzPath, ReadyzPath) splayed out, while the config side already groups them as TelemetryPaths. The two shapes had to stay in sync field-by-field — a future renaming touched two places, a maintenance trap. Hoist into telemetry.Paths sub-struct so the YAML → ServerConfig mapping is mechanical: cfg.Paths.Metrics ↔ telemetry.Paths.Metrics (same field name) cfg.Paths.Healthz ↔ telemetry.Paths.Healthz cfg.Paths.Readyz ↔ telemetry.Paths.Readyz Trailing `_ struct{}` on telemetry.Paths keeps field additions non-breaking. All ServerConfig literals updated: 7 in tests + 1 in cmd/tracecore. Validation errors now reference "Paths.Metrics" rather than "MetricsPath", matching the field path. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Address item #1: the 292-line internal/selftelemetry/impl.go mixed three concerns (receiver impl + exporter impl + init-error tracking), forcing readers to context-switch across responsibilities. Split: receiver_impl.go (~200 lines) — NewReceiver, receiverImpl, the five-method binding, degraded- seconds bookkeeping exporter_impl.go (~80 lines) — NewExporter, exporterImpl, FailureRateReader satisfaction init_errors.go (~40 lines) — RecordInitError Common state hoisted to receiver_impl.go: ErrNilMeterProvider sentinel and `instrumentationScope` constant (the package-stable Meter scope name shared across all three call sites). No API change; tests pass without modification. Each file is now a single coherent unit and a future maintainer reading "what does NewExporter do?" doesn't have to scroll past Receiver internals. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Address item #2: the rolling-window failure-rate math was baked into AggregateSLOSource (~80 lines of ring-buffer + underflow guard + 2× window pruning + maxSamples cap). When the future queue mechanism and runtime-restart mechanism land — both with their own SLI gauges — they'd need the same math. Extract into a standalone WindowedRate primitive in internal/telemetry/windowed_rate.go. AggregateSLOSource is now a thin walker over the exporter registry that delegates the math: rate := s.rate.Observe(failure, success+failure) Public API: NewWindowedRate(window) → *WindowedRate (*WindowedRate).Observe(numerator, denominator) → float64 Same semantics as before (warming-up returns 0, underflow returns 0, zero-delta returns 0), now with five focused tests pinning each contract (warming up, rate-over-window, underflow safety, zero-delta, default window). AggregateSLOSource shrinks from ~120 lines to ~25 lines of glue. When queue.depth_ratio gets a real source in a future milestone, its callback drops in `NewWindowedRate(...)` + `Observe(depth, capacity)` and inherits the same bounded-memory + monotonic-safe behavior for free. make ci clean. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Address item #3: `syncBuffer` was duplicated in cmd/tracecore + internal/telemetry, and `failingSink` lived only in clockreceiver even though M8/M9 will need the same downstream-error stub. Hoisted into `internal/pipeline/pipelinetest`: pipelinetest.SyncBuffer (was syncBuffer ×2) pipelinetest.RecordingMetricsSink (new — for capturing pushes) pipelinetest.FailingMetricsSink (was failingSink ×1) Migrations: - cmd/tracecore/integration_test.go: drops 19-line syncBuffer def, type alias to pipelinetest.SyncBuffer (call sites unchanged). - internal/telemetry/server_test.go: same alias pattern. - components/receivers/clockreceiver/errors_integration_test.go: drops failingSink, uses pipelinetest.FailingMetricsSink{Err: ...}. clockreceiver_test.go's metricsSink intentionally not migrated — it's package-internal, tightly coupled to a few test assertions, and migration cost exceeds value for this PR. M8/M9 + future receivers reach for pipelinetest.RecordingMetricsSink instead. Coverage: internal/pipeline/pipelinetest 77.3% → 86.8% via new helper tests. Other packages unchanged. make ci clean. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Address item #4: runCollect was orchestrating 13 distinct steps in ~125 lines. Hard to read top-down; hard to test individual phases in isolation. Extract two narrow helpers: registerObservability(mp, pipelines, buildInfo, revision) error Registers the SLO observable gauges + the build_info join-target on the MeterProvider. No-op when telemetry is disabled. runRuntime(ctx, logger, pipelines, drainBudget, ready, srv, mp) int Starts the runtime, flips /readyz, blocks on signal, performs the ordered shutdown: ready=false → rt.Shutdown → telemetry shutdown. Returns the exit code. runCollect now reads top-down as a short sequence: 1. log starting 2. load config + build BuildInfo 3. initTelemetryStack (Phase 2) 4. BuildPipelines 5. registerObservability ← new helper 6. runRuntime ← new helper Each helper takes only what it needs (no closure-over-closure on runCollect's locals); easier to test the orchestration shape in isolation when M-something adds a tracing surface. No behavior change. make ci clean. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Address item #8: operators setting `telemetry.enabled: true` and nothing else couldn't easily see what port tracecore would actually bind to. The full config is in their YAML mentally, but the default-resolution rules live in code. Surface them. New `tracecore validate --config=foo.yaml --explain`: config valid: 1 pipeline(s) metrics/primary: receivers=1 processors=0 exporters=1 resolved configuration (after defaults applied): telemetry.enabled: true telemetry.listen: localhost:8888 telemetry.paths.metrics: /metrics telemetry.paths.healthz: /healthz telemetry.paths.readyz: /readyz pipelines: metrics/primary: receivers: [clockreceiver] exporters: [stdoutexporter] When telemetry is disabled the block notes "HTTP surface OFF; no port bound" — so operators see telemetry.enabled defaulting to false even without the YAML key present. Two integration tests: - TestIntegration_ValidateExplain_DumpsResolvedConfig: defaults resolve correctly for an "enabled: true with nothing else" YAML. - TestIntegration_ValidateExplain_TelemetryOff: disabled branch surfaces the off state explicitly. Behavior unchanged when --explain is absent; exit codes identical. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Address items #10 (deprecation policy for self-metric names) and #11 (JSON content negotiation on /healthz + /readyz). JSON probes: - /healthz + /readyz now honor `Accept: application/json` and return `{"status":"ok|ready|not ready|shutting down"}` with Content-Type application/json. Default (no Accept or Accept: text/plain) stays text/plain so k8s probes + curl are unchanged. - Hand-rolled JSON to keep encoding/json off the hot scrape path; status strings are operator-set constants so no quoting risk. - Cache-Control: no-store applies to both content types. - Test pins six cases covering both paths, with/without Accept, malformed Accept, and the text-beats-json precedence case. Deprecation policy (RFC-0006 new section): - Pre-1.0 (M2–M7): tracecore reserves the right to rename without procedure; the surface is still settling. CHANGELOG calls out any rename as "no bridge window: pre-1.0 contract." - Post-1.0: any rename gets an RFC, then a bridge window (≥1 minor release emitting BOTH names simultaneously) backed by a `tracecore_deprecated_metric{old_name, new_name}` counter so operators see dashboards still asking for the old name. Removal after the bridge window, flagged loudly in `[Removed]` + release-notes `[CHANGE]`. This is the documented commitment operators alerting on these metrics need before they take a hard dependency. Coverage: internal/telemetry 84.4% → 86.9% via new probe tests. make ci clean. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Address item #7: internal/telemetry had two export_test.go files (export_test.go + server_addr_export_test.go), each containing one test-only re-export. Go convention is one export_test.go per package; the split was an artifact of incremental work. Merge HTTPAddr into export_test.go alongside StartWithListenerForTest with a header comment establishing the file as the package's single test-escape-hatch home. Delete server_addr_export_test.go. No behavior change; test compilations unchanged. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Apply 3 reviewer strong findings:
1. **selfExporterCarrier promoted to selftelemetry.ExporterCarrier.**
Previously the carrier interface lived in cmd/tracecore as invisible
duck-typing; future binary entry points would have to re-define it.
Now a public contract in the selftelemetry package with a
receiver-author template in the godoc. stdoutexporter already
satisfies it; clockreceiver inherits the example.
2. **SetDegraded mutex dropped.** muSetDegraded was redundant against
atomic.Pointer — CAS-only is the canonical pattern. Replaced the
switch-on-current-value with:
degraded=true → CompareAndSwap(nil, &now)
degraded=false → Swap(nil) + accumulate.Add
Hot-path no longer takes a lock. Microsecond-scale read race in
the observable callback documented in the new SetDegraded comment
(under-count self-corrects on the next scrape, matches histogram
bucket precision).
3. **IncError two-attribute merge collapsed to one call.** Previously
the OTel SDK merged WithAttributeSet(r.attrs) + WithAttributes(kind)
via documented-implementation-detail semantics. Now passes a single
WithAttributes with both component_id + kind, the spec-stable shape.
Bonus: atomic style normalized — `accumulated` and `activityUnix`
were pointer-typed (&atomic.Uint64{}) for no reason while degradedAt
was value-typed. Both flavors work via embedding; value-typed is the
modern idiom (atomic.Uint64 from go1.19+). Receiver-impl is now
consistently value-typed atomics.
Tests pass without modification — the public surface and observable
contracts are preserved.
Assisted-by: Anthropic:claude-opus-4-7 [Claude Code]
Signed-off-by: Tri Lam <trilamsr@gmail.com>
Three reviewer-flagged simplifications:
1. **Probe JSON payloads pre-marshaled at package init.** Replaces
hand-rolled string concatenation with encoding/json — the
marshal cost is paid once for {"ok","ready","not ready",
"shutting down"}, hot path writes pre-encoded bytes. Removes the
maintenance trap of "what if status ever needs quoting" and
pulls in encoding/json (already transitive via yaml.v3).
2. **PromHandler cached in MeterProvider.** Previously re-created
`promhttp.HandlerFor(reg, opts)` on every PromHandler() call.
Now set once at NewMeterProvider, exposed via the field. Saves
the closure allocation per scrape.
3. **registerObservableFloat64Gauge helper.** RegisterSLOMetrics had
three near-identical Float64ObservableGauge blocks; STYLE.md's
"three similar lines is the threshold" rule applies. New
sloGaugeSpec struct + helper function reduces three 8-line
blocks to three 5-line entries in a slice.
wantsJSON gains a docstring noting it substring-matches Accept rather
than parsing RFC 7231 q-values; operators wanting q-value-aware
negotiation belong behind a reverse proxy.
No behavior change. make ci clean.
Assisted-by: Anthropic:claude-opus-4-7 [Claude Code]
Signed-off-by: Tri Lam <trilamsr@gmail.com>
Address reviewer findings on duplication + missing context: 1. **Path validation lived in two places** with mismatched strictness: internal/config did "leading /"; internal/telemetry/server did "leading / + no whitespace + no query/fragment". Stricter rules on the server side meant a config that passed `tracecore validate` could still surface a panic at server.start time. Promoted the strict rules to `config.ValidateMountPath`; the server-side validator now delegates. One source of truth. 2. **WindowedRate gets a rationale comment.** A reviewer asking "why a custom 131-line primitive when golang.org/x/time/rate exists?" now finds the answer in the docstring: x/time/rate is a token-bucket limiter (wrong semantics); PromQL rate() runs server-side and can't emit during boot when the SLO gauge needs to surface. The math is small enough to own. 3. **AggregateSLOSource.ExporterFailureRate gains an O(n) note.** "Walk cost is O(n) in registered exporters... benchmarked <5µs for 100 readers on M4 Pro" — anchors the perf claim to the existing benchmark file so a future reader debugging scrape latency knows where to look first. No behavior change; all tests pass without modification. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Two closures from the reviewer + the M2 prompt artifact:
1. **Fd-count fault-injection added to TestServer_RepeatedStartShutdown_NoLeaks.**
Previously only goleak ran — catches goroutine leaks but not fd
leaks. Now also samples /proc/self/fd (Linux) or /dev/fd (macOS)
before + after 10 Start/Shutdown cycles; a listener leak of
1 fd/cycle produces a delta ≥10. Slack of 3 absorbs legitimate
test-runtime fd churn. Skips gracefully on platforms without
either path (the goleak check still runs).
2. **docs/loops/m2-self-telemetry.md success-criteria checkboxes
ticked.** All 19 are now [x] with one-line evidence each pointing
at the commit / test / RFC section that satisfies them. Two
notable annotations:
- Criterion 8 (clockreceiver covers all 5 receiver methods):
4 surface in TelemetrySurface_EndToEnd; 5th
(errors_total) covered by ErrorsTotal_SurfacesOnDownstreamFailure
because normal clockreceiver→stdoutexporter doesn't fail.
- Criterion 13 (M8/M9 rebase): verified non-destructively via
`git merge-tree`; zero Go-code conflicts on either branch.
The m2 prompt file is gitignored (docs/loops/), so this commit doesn't
push anything operator-visible — it's the local artifact gating the
M2 COMPLETE promise. Walking back to mark progress closes the same
"declared-before-done" pattern the M2 lessons section in FOLLOWUPS
calls out.
Assisted-by: Anthropic:claude-opus-4-7 [Claude Code]
Signed-off-by: Tri Lam <trilamsr@gmail.com>
Two passes: 1. **Comment trim.** Walked new code with "address why not what" as the rule. Removed restatements of obvious behavior; kept rationale comments (cardinality-tradeoff, slowloris-defense, atomic-style-consistency, package-stable-scope, etc.) and exported-symbol doc-comments the linter requires. Net: ~60 lines of comment churn out of code that explained behavior the identifier already named. 2. **Phased-deferral index added to FOLLOWUPS.md.** Every M2 review round (Loop 4 passes × 2 agents, then 10 self-review phases, then 4 A+ reviewer batches) now has its commit indexed and its deferred items collated into a single table with "trigger to revisit" hints. A future maintainer (or future-me) opening FOLLOWUPS sees: - which commit closed which review - which deferrals are still open - what event flips each from deferred to actionable This is the artifact M-something needs to scan before opening new tickets — answers "did we already decide on X?" without re-reading the entire PR thread. Coverage holds (pipelinetest 86.8%, selftelemetry 90.1%, telemetry 88.0%). make ci clean. Assisted-by: Anthropic:claude-opus-4-7 [Claude Code] Signed-off-by: Tri Lam <trilamsr@gmail.com>
Reviewer's post-A+ pass flagged ecosystem-fit gaps. Land items 1-3
+ 5 + 7 in-scope; rest cataloged in FOLLOWUPS with milestone targets.
1. **docs/examples/prometheus-alerts.example.yaml** — 5 starter
alert rules covering the operationally meaningful failure modes:
ExporterFailureRateHigh, ReceiverDegraded, ReceiverNoActivity,
SelftelemetryInitErrors, BuildIdentityKnown (scaffolding for
fleet version-drift). Operators include under rule_files: in
prometheus.yml or convert to a PrometheusRule CRD.
2. **selftelemetry.NewCapturingReceiver** — test helper recording
every call from all 5 Receiver methods. Concurrent-safe
accessors return copies. M10+ receiver authors stop reinventing
this — half an hour saved per receiver.
3. **TLS schema sketch in RFC-0006** — `telemetry.tls: { enabled,
cert_file, key_file, client_ca_file, min_version }` plus
semantics (mTLS via client_ca_file; SIGHUP reload). Documents
the shape so when TLS lands the config schema is stable. M2
still ships plaintext-only with reverse-proxy as the
documented near-term path.
5. **selftelemetry.Reason* constants** — mirrors the Kind* pattern:
ReasonNilProvider, ReasonInstrumentRegister, ReasonUnsupportedSDK
plus CanonicalReasons() + IsCanonicalReason() helpers.
clockreceiver + stdoutexporter updated to use the constants
rather than string literals.
7. **Histogram bucket tuning** for
`tracecore.receiver.collection_latency_seconds`. Default OTel
buckets miss sub-millisecond resolution; new boundaries
[100µs..10s] log-spaced cover both a 200µs collection cycle
and a 2s slow one with distinct buckets. Closes the Loop-2
carry-forward.
**Documented as ecosystem-fit deferrals in FOLLOWUPS** (items 4, 6,
8, 9, 10 from the reviewer's list): Helm chart (M5b), Mermaid arch
diagram (M3), `version --bundle` CLI (M3), overhead numbers in
README (M3), threat model 1-pager (M3), plus the smaller items the
reviewer noted in passing (OpenMetrics toggle for M5, recording
rules + Grafana dashboard for M4, Server header strip
opportunistic, /metrics rate limit for M5, SBOM summary for M3).
Each carries a "suggested target" hint for the milestone planner.
Coverage holds: selftelemetry 89.7%, telemetry 88.0%. make ci clean.
Assisted-by: Anthropic:claude-opus-4-7 [Claude Code]
Signed-off-by: Tri Lam <trilamsr@gmail.com>
Five "diminishing returns" items the post-A+ reviewer flagged. All
ship — the last review called these "the kind of PR you'd ship as
a reference."
1. **Mermaid architecture diagram in RFC-0006.** Three-layer flow
(components → SDK → surface) with the operator/k8s touch points
on the right. The two dashed-line extensions for M3+
(TracerProvider parallel, OTLP push reader parallel) are
called out in prose so the diagram doesn't need re-drawing
when tracing lands.
2. **Concrete benchmark numbers in `internal/telemetry/README.md`
Performance section.** Median across 3-5 runs on Apple M4 Pro:
- AggregateSLOSource.ExporterFailureRate: ~3.85µs (1 reader),
~3.87µs (10), ~4.51µs (100). 0 allocs steady-state.
- WindowedRate.Observe (primitive): ~3.85µs. 0 allocs.
At 15s scrape: 0.00003% of one core. Bench numbers map to
NORTHSTARS O2's per-receiver overhead budget (<0.05%).
New BenchmarkWindowedRate_Observe isolates the primitive cost
for future SLI authors sizing their own gauges.
3. **`docs/examples/grafana-dashboard.example.json`.** Nine panels:
build identity (table), failure_rate (timeseries with
thresholds), calls_total rate by result, emissions per
component, latency p50/p95/p99, activity staleness with
threshold colors, errors by kind, degraded-seconds rate,
selftelemetry init errors. Templated by `instance` + `component_id`
so federated dashboards Just Work. Operators import via
Grafana → New → Import.
4. **`make bench-check` Makefile target + frozen baseline at
`internal/telemetry/testdata/bench-baseline.txt`.** Runs the
current benchmark set against the baseline via `benchstat`;
prints the geomean delta. CI gate is a FOLLOWUPS item (don't
block PRs on perf during heavy refactor weeks); manual
`make bench-check` available now.
5. **`internal/telemetry/SECURITY.md` 1-pager threat model.**
Single attacker class (network principal reaching the listen
socket); goals table; mitigations table mapping each Server
field to the attack it bounds; "not mitigated in M2" table
pointing at the FOLLOWUPS rows; recommended production
deployment posture (reverse proxy + NetworkPolicy + unpriv
user). Closes the auditor-lens gap the reviewer flagged.
Coverage unchanged. make ci clean.
Assisted-by: Anthropic:claude-opus-4-7 [Claude Code]
Signed-off-by: Tri Lam <trilamsr@gmail.com>
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## What landed (at a glance) | Area | Shipped | |---|---| | Bench-regression gate | `scripts/bench-check.sh` parses benchstat `+NN.NN%` deltas and exits non-zero if any row exceeds the threshold | | Makefile target | `make bench-check` (with `THRESHOLD=N` override) delegates to the wrapper | | README correction | `internal/telemetry/README.md` regression-detection section rewritten to describe actual behavior | ## What this PR does Post-merge fix for the M2 self-telemetry PR (#17). The `make bench-check` target in that PR claimed "fails if any row regresses >10%" — but `benchstat` itself always exits 0, so the target reported deltas without gating on them. Caught by the post-merge reviewer. Wraps benchstat in `scripts/bench-check.sh`: - Runs the benchmark output through benchstat (printed verbatim so operators still see the comparison table) - Awk-parses the per-row `+NN.NN%` deltas - Exits 1 if any benchmark regressed by more than the configured threshold; prints the offending row + delta to stderr Tested locally: - Identical input files → `PASS`, exit 0. - Synthetic +31% regression → `REGRESSION: WindowedRate_Observe-14 +31.28%` + exit 1. POSIX-awk compatible (BSD awk on macOS, gawk on Linux). README's regression-detection section rewritten to match actual behavior and document the "intentional regression — update the baseline" workflow. ## Linked issue(s) Refs #17 (post-merge fix). ## Release notes \`\`\`release-notes NONE \`\`\` ## Checklist - [x] Tests added or updated — manual end-to-end test of both pass + fail paths documented in commit message; baseline file unchanged so the gate is a no-op until someone actually regresses. - [x] \`make ci\` passes locally - [x] Commits are signed off (\`git commit -s\`) - [x] Commits cryptographically signed (SSH) - [x] N/A — no new components --------- Signed-off-by: Tri Lam <trilamsr@gmail.com>
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Two independent reviews of PR #18 surfaced a stack of blockers, strong findings, and quality lifts. This commit lands the tractable items (defers documented in docs/FOLLOWUPS.md M8 section). Operator-visible drift (closes Reviewer 2 #13-#17): - RUNBOOK kind-triage row `consume` → `downstream` (last commit renamed the kind but missed the doc table). - README config table: `initial_delay` range updated from "0.. collection_interval" to "≥ 0" (code already relaxed for DGX cold-starts; doc was stale). - prometheus-alerts: DCGMReceiverHighErrorRate threshold changed from `rate > 0.1/sec` (unreachable: 15s default tick caps at 0.067/sec) to `increase > 5 in 5m`. Stale "M2 has not landed" caveat removed. - example_config: single `mode:` line with a clarifying comment (was showing both `mode: standalone` and `# mode: embedded`, inviting operators to uncomment both → YAML duplicate-key). - cmd/tracecore receivers list now prints `dcgm [stub]` / `dcgm [cgo]` so operators can verify deploy shape without reading go.mod. Build-tag-conditional via three small files in cmd/tracecore (receiver_variants*.go) — pattern extends to M11 NVML. Correctness bugs (closes Reviewer 2 #2, #3, #4, #6, #7): - receiver.Shutdown: `r.running.CompareAndSwap(true, false)` gates teardown so a second Shutdown is a no-op (cgo libdcgm `dcgmShutdown` is not documented idempotent). Same CAS provides the happens-before for `r.cancel` publish that Pass-1 flagged. - receiver.ensureWatched: zero-entities path now emits IncError(KindEnumerate) + degraded rather than returning true. Without this, a misconfigured host (no GPUs visible, ACL blocks /dev/nvidia*) had the receiver looking healthy while emitting nothing. - receiver: new `warnOnce` helper gates the 7 per-tick failure- path Warn logs to fire only on the first failure after recovery. Closes the log-storm bug (4 errors/min × 60 min = 240 lines). Counter (`receiver_errors_total`) still ticks every failure. - metrics.applyCardinalityCap: parameter `cap` → `maxSeries` (cap shadowed the Go builtin). Quality / contract lifts: - metrics.emit now returns a `stale` count for StatusStale and StatusError samples. pushSamples calls IncError(KindRead) once per tick when stale > 0 — surfaces DCGM serving slow/faulty data, which is precisely what StatusStale exists for. Per-tick not per-sample so GPU count doesn't inflate the rate. (StatusNoData and StatusFieldNotSupported still silent.) - docs_parity_test.go: new TestRUNBOOK_KindsMatchEmitted walks every emitted IncError/failedTick kind against the RUNBOOK per-kind triage table in both directions. This is the structural fix for the bug class — RUNBOOK can never again drift from emitted kinds without CI failure. - receiver.go: promoted `watchUpdateDivisor` / `watchKeepForMultiplier` / `watchUpdateEveryMinimum` constants for the previously-magic DCGM watch-cadence ratios. Documentation + dedup: - dcgm README: new "Privacy + data residency considerations" subsection (compliance-auditor ask). Flags hw.id / pci.bdf / NVLink peer IDs as quasi-identifying; provides two mitigation patterns (attr-drop processor, salt-hash pseudonymization). - docs/agents/examples/constructor_options.go: `WithTelemetry` renamed to `WithSelfTelemetry` to match the real in-tree receiver API. M9+ authors copying the example no longer drift. - RUNBOOK kind enumeration line restored with both watch and mig (dcgm-local kinds) per the last commit's promotion. - Repo-root `FOLLOWUPS.md` consolidated into `docs/FOLLOWUPS.md` (M8-opportunistic + M8-skipped sections). Single source of truth; 17 deferred items pulled forward with falsifiable triggers (cgo client landing, M11 sibling-receiver shape, operator-report thresholds, file-size triggers). - All bare `FOLLOWUPS.md` references updated to `docs/FOLLOWUPS.md`. Honest pushback documented: - I disagree with the M8-AGRADE-GAP claim of Operator UX 3.7→4.0. The drift findings above are exactly the class of bugs that rubric criterion was supposed to prevent — the alerts-vs-RUNBOOK parity test existed but didn't check kind values against emitted call sites. The new TestRUNBOOK_KindsMatchEmitted closes that gap; future operator-UX claims should pin to a test like this. - Deferred: split receiver.go (475 LOC) into 3 files, hoist dcgmtest.BaseClient, SECURITY.md for receiver, dcgm_info join-target, libdcgm setup in CONTRIBUTING — all logged with triggers. Reviewer 1's "construct receiver via M9-style primary-Option" inconsistency goes in the queue for M9-close review. `make ci` passes; dcgm coverage 86.0% (essentially flat — new tests offset by widened emit signature in test paths). Assisted-by: Claude Opus 4.7 Signed-off-by: Tri Lam <trilamsr@gmail.com>
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What landed (at a glance)
/metrics+/healthz+/readyzon one listener; default-OFF; defaultlocalhost:8888; slowloris timeouts; panic-recovery middleware; JSON content negotiation;Cache-Control: no-storeon probesinternal/telemetry/server.go, RFC-0006selftelemetry.Receiver(5 methods) +selftelemetry.Exporter(call success/failure) +FailureRateReader+ExporterCarrier;Kind*canonical constants +IsCanonicalKindselftelemetry.Processor; runtime cap onIncError(kind)cardinalityinternal/selftelemetry/*.goPromHandler, idempotentShutdownMetricsLevelknobinternal/telemetry/meter_provider.gotracecore.exporter.failure_rate(real signal, rolling 60s window viaWindowedRate),tracecore.queue.depth_ratio(honest zero),tracecore.component.restart_count_per_hour(honest zero); rawtracecore.exporter.calls_total{result,kind}counterfailure_rate{component_id}; histogram bucket tuninginternal/telemetry/slo.go+windowed_rate.gotracecore_build_info{command,version,revision}Prom join-target; label-name validationinternal/telemetry/build_info.goCreateSettingsgainsBuildInfo+_ struct{}guard;TelemetrySettingsgainsMeterProvider+_ struct{}guard;pipelinebuilderauto-populatesResourcewithhost.name/service.{name,version,instance.id}Settingssplit (post-v1);TracerProviderfield (tracing milestone)internal/pipeline/{component,factory}.go,internal/pipelinebuilder/builder.goHost.ReportStatusmethod → free fninternal/componentstatus.ReportStatus(host, ev);StatusReporteropt-in interfaceinternal/componentstatus/clockreceiver+stdoutexporteras canonical examples; selftelemetry init-failure surfaces astracecore.selftelemetry.init_errors_totalgit merge-tree)components/receivers/clockreceiver/clockreceiver.go,components/exporters/stdoutexporter/stdoutexporter.gorunCollect→initTelemetryStack+registerObservability+runRuntimehelpers; shutdown errors logged;--versionincludes OTel SDK + Prom exporter versions;validate --explaindumps resolved configvalidate --explainprovenance (default vs explicit)cmd/tracecore/{collect,validate,main}.gotelemetry: { enabled, listen, paths }block; defaults applied;config.ValidateMountPathis the single source of truth for path validationinternal/config/config.gopipelinetest.{SyncBuffer,RecordingMetricsSink,FailingMetricsSink}; goleak + fd-count fault injection; benchmark (<5µsat 100 readers, 0 allocs); example godoc testsselftelemetry.NewRecordingReceiver(t)helper; q-value-awareAcceptparserinternal/pipeline/pipelinetest/fakes.go,internal/telemetry/{leak,slo_bench}_test.gointernal/telemetry/README.md(operator quickstart + security posture + perf table); package doc.go files;docs/examples/with-telemetry.yaml(CI-gated); MILESTONES + FOLLOWUPS + FAILURE-MODES updatedHost.ReportStatus,CreateSettings,TelemetrySettings); 3 new permanent rows (localhost:8888default,tracecore.*namespace, in-treecomponentstatus)docs/STRATEGY.mdProcess
docs/FOLLOWUPS.mdwith revisit triggers.Assisted-by:trailer; no history rewrites; branch offmain; PR opened viaprskill.STRATEGY divergence table changes
Host.ReportStatusCreateSettingsshapeTelemetrySettingsshapelocalhost:8888(security tiebreaker over OTel0.0.0.0:8888)tracecore.*(separate surface fromotelcol_*)componentstatuslocationinternal/componentstatus(revisit at M22)Linked issue(s)
N/A — milestone work tracked in MILESTONES.md §M2.
Release notes
Checklist
make cipasses locally — lint clean, all tests pass under-race, coverage above floors (selftelemetry 90.1%, telemetry 88.0%, componentstatus 100%, config 95.2%, clockreceiver 91.2%, pipelinetest 86.8%), govulncheck clean, doc-check 31 refs verified.git commit -s)internal/packages + existing component wire-ups)