Deflake pkg/trace/writer by isolating tests from each other - #55614
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TestStatsSyncWriter/ok failed on main with `gzip: invalid header`, alongside seven `use of closed network connection` panics from the test server. The same signature hit TestTraceWriterMultipleEndpointsConcurrent earlier; the fix then (#55406) only removed a follow-on nil deref, so the cause was never found. A body that is not valid gzip means the first bytes were not 1f 8b, so it was never a writer payload at all. The package's tests were not isolated: several created writers whose senders were never stopped, and test servers that were never closed. newSender starts ConnectionLimit worker goroutines immediately, so a forgotten writer left workers, an HTTP client and a bound listener alive for every later test to interact with, and a closed listener's ephemeral port can be handed to a later test's server. Test isolation: - cleanupWriter gives every stats test ownership of its writer and server, stopping senders before closing the server. - Stop the five trace writers that were never stopped, and close the test server in TestTraceWriterMultipleEndpointsConcurrent, which was the only listener in trace_test.go left bound. - TestMain fails an otherwise-green run that leaks sender goroutines. This is what found the five leaks above. Diagnostics, so the next occurrence names its own cause: - The test server records each accepted request with its remote address, listener, headers and body prefix, and flags a body carrying the expectResponses marker, which is the one non-gzip body in the package. - assertPayload, payloadsContain and payloadsContainV1 assert how many requests arrived before decoding any, and print that provenance on failure. Two call sites whose counts are genuinely nondeterministic opt out with a documented sentinel. - The server no longer panics when a request body read fails. That is ordinary when a server closes with a request in flight, and a suspected panic makes the CI harness skip the rerun pass. It now records the error and aborts the connection with http.ErrAbortHandler, preserving the old transport-error semantics for the sender without the stack trace. Sender fixes found while reading the shutdown path: - Push counted a payload as inflight after queuing it, so FlushSync and Stop could observe zero while a payload was already queued and return before it was sent. - Stop is idempotent and now waits for its worker goroutines, bounded by the same five second budget the inflight wait uses so a worker asleep in backoff cannot stall agent shutdown. Validation: pkg/trace/writer and pkg/trace/... pass with and without -race; 20 consecutive full-package runs and 10 with -race are green; linter.go reports no issues. The new ErrAbortHandler behaviour is covered by TestTestServer/truncated-body, verified to fail if that change is reverted. Not addressed here: Stop can still close the queue under a producer blocked on a full queue once the five second wait expires, which predates this change and wants its own fix. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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AI review by Codex (OpenAI) - workflow run
Patch is incorrect: shutdown can now block for roughly 15 seconds despite documenting a five-second budget, and the release note claims behavior the code does not implement.
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| func (s *sender) Stop() { | ||
| s.WaitForInflight() | ||
| s.mu.Lock() | ||
| s.closed = true | ||
| s.mu.Unlock() | ||
| close(s.queue) | ||
| s.stopOnce.Do(func() { | ||
| // Wait once before closing, so that payloads already inflight keep their | ||
| // full retry budget. | ||
| s.WaitForInflight() | ||
| s.mu.Lock() | ||
| s.closed = true | ||
| s.mu.Unlock() | ||
| // Push increments inflight while holding a read lock, so any Push that | ||
| // observed !closed has already been counted by the time the write lock | ||
| // above is acquired. Waiting again here therefore cannot miss a payload | ||
| // that raced with the close, and guarantees the channel is only closed | ||
| // once no producer can still be sending on it. | ||
| s.WaitForInflight() |
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Each of the two WaitForInflight calls gets its own five-second timer, and waitTimeout below gets a third. If a request remains stuck, Stop can therefore take about 15 seconds, regressing the previous five-second shutdown bound. Use one shared deadline/budget across all three waits.
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| closed, and is safe to call more than once. Payloads handed to a sender | ||
| that is already stopped are returned to the payload pool instead of being | ||
| dropped without being recycled. |
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This recycling claim is not implemented: Push still returns immediately when s.closed is true without returning p to its pool. Either implement the stated behavior or remove it from the release note.
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| conn, err := net.Dial("tcp", strings.TrimPrefix(ts.URL, "http://")) | ||
| assert.NoError(err) |
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If net.Dial fails, assert.NoError continues and the following conn.Close()/type assertion dereferences a nil connection, hiding the actual failure. Use require.NoError before accessing conn.
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🎯 Code Coverage (details) 🔗 Commit SHA: 2fc896c | Docs | View more details | Give us feedback! |
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Files inventory check summaryFile checks results against ancestor ac3e2c30: Results for datadog-agent_7.84.0~devel.git.582.2fc896c.pipeline.134034001-1_amd64.deb:No change detected Results for datadog-iot-agent_7.84.0~devel.git.582.2fc896c.pipeline.134034001-1_amd64.deb:No change detected |
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Static quality checks✅ Please find below the results from static quality gates Successful checksInfo
28 successful checks with minimal change (< 2 KiB)
|
Regression DetectorRegression Detector ResultsMetrics dashboard Baseline: ac3e2c3 Optimization Goals: ✅ No significant changes detected
|
| perf | experiment | goal | Δ mean % | Δ mean % CI | trials | links |
|---|---|---|---|---|---|---|
| ➖ | quality_gate_security_idle | memory utilization | +0.50 | [+0.45, +0.55] | 1 | Logs bounds checks dashboard |
| ➖ | quality_gate_idle | memory utilization | +0.08 | [+0.03, +0.12] | 1 | Logs bounds checks dashboard |
| ➖ | dsd_uds_10mb_3k_timestamped_contexts_memory | memory utilization | +0.03 | [-0.19, +0.24] | 1 | Logs |
| ➖ | quality_gate_idle_all_features | memory utilization | +0.00 | [-0.04, +0.04] | 1 | Logs bounds checks dashboard |
| ➖ | quality_gate_private_action_runner | memory utilization | -0.04 | [-0.16, +0.09] | 1 | Logs bounds checks dashboard |
| ➖ | quality_gate_security_no_fs_load | memory utilization | -0.05 | [-0.13, +0.04] | 1 | Logs bounds checks dashboard |
| ➖ | quality_gate_security_mean_fs_load | memory utilization | -0.16 | [-0.20, -0.13] | 1 | Logs bounds checks dashboard |
| ➖ | quality_gate_logs | % cpu utilization | -0.17 | [-1.03, +0.69] | 1 | Logs bounds checks dashboard |
| ➖ | quality_gate_metrics_logs | memory utilization | -0.85 | [-1.08, -0.62] | 1 | Logs bounds checks dashboard |
| ➖ | dsd_uds_10mb_3k_timestamped_contexts_cpu | % cpu utilization | -1.72 | [-1.97, -1.46] | 1 | Logs |
Bounds Checks: ✅ Passed
| perf | experiment | bounds_check_name | replicates_passed | observed_value | links |
|---|---|---|---|---|---|
| ✅ | quality_gate_idle | intake_connections | 10/10 | 4 = 4 | bounds checks dashboard |
| ✅ | quality_gate_idle | memory_usage | 10/10 | 176.15MiB ≤ 179MiB | bounds checks dashboard |
| ✅ | quality_gate_idle | total_bytes_received | 10/10 | 748.78KiB ≤ 819.20KiB | bounds checks dashboard |
| ✅ | quality_gate_idle_all_features | intake_connections | 10/10 | 4 = 4 | bounds checks dashboard |
| ✅ | quality_gate_idle_all_features | memory_usage | 10/10 | 519.87MiB ≤ 537MiB | bounds checks dashboard |
| ✅ | quality_gate_idle_all_features | total_bytes_received | 10/10 | 1.14MiB ≤ 1.25MiB | bounds checks dashboard |
| ✅ | quality_gate_logs | intake_connections | 10/10 | 20 ≤ 40 | bounds checks dashboard |
| ✅ | quality_gate_logs | memory_usage | 10/10 | 214.24MiB ≤ 220MiB | bounds checks dashboard |
| ✅ | quality_gate_logs | missed_bytes | 10/10 | 0B = 0B | bounds checks dashboard |
| ✅ | quality_gate_logs | total_bytes_received | 10/10 | 263.10MiB ≤ 292MiB | bounds checks dashboard |
| ✅ | quality_gate_metrics_logs | cpu_usage | 10/10 | 373.67 ≤ 2000 | bounds checks dashboard |
| ✅ | quality_gate_metrics_logs | intake_connections | 10/10 | 17 ≤ 40 | bounds checks dashboard |
| ✅ | quality_gate_metrics_logs | memory_usage | 10/10 | 419.03MiB ≤ 455MiB | bounds checks dashboard |
| ✅ | quality_gate_metrics_logs | missed_bytes | 10/10 | 0B = 0B | bounds checks dashboard |
| ✅ | quality_gate_metrics_logs | total_bytes_received | 10/10 | 0.94GiB ≤ 1.04GiB | bounds checks dashboard |
| ✅ | quality_gate_private_action_runner | memory_usage | 10/10 | 72.95MiB ≤ 75MiB | bounds checks dashboard |
| ✅ | quality_gate_security_idle | cpu_usage | 10/10 | 29.42 ≤ 100 | bounds checks dashboard |
| ✅ | quality_gate_security_idle | memory_usage | 10/10 | 326.63MiB ≤ 355MiB | bounds checks dashboard |
| ✅ | quality_gate_security_mean_fs_load | cpu_usage | 10/10 | 73.66 ≤ 200 | bounds checks dashboard |
| ✅ | quality_gate_security_mean_fs_load | memory_usage | 10/10 | 305.22MiB ≤ 335MiB | bounds checks dashboard |
| ✅ | quality_gate_security_no_fs_load | cpu_usage | 10/10 | 22.78 ≤ 100 | bounds checks dashboard |
| ✅ | quality_gate_security_no_fs_load | memory_usage | 10/10 | 311.90MiB ≤ 345MiB | bounds checks dashboard |
Explanation
Confidence level: 90.00%
Effect size tolerance: |Δ mean %| ≥ 5.00%
Performance changes are noted in the perf column of each table:
- ✅ = significantly better comparison variant performance
- ❌ = significantly worse comparison variant performance
- ➖ = no significant change in performance
A regression test is an A/B test of target performance in a repeatable rig, where "performance" is measured as "comparison variant minus baseline variant" for an optimization goal (e.g., ingress throughput). Due to intrinsic variability in measuring that goal, we can only estimate its mean value for each experiment; we report uncertainty in that value as a 90.00% confidence interval denoted "Δ mean % CI".
For each experiment, we decide whether a change in performance is a "regression" -- a change worth investigating further -- if all of the following criteria are true:
-
Its estimated |Δ mean %| ≥ 5.00%, indicating the change is big enough to merit a closer look.
-
Its 90.00% confidence interval "Δ mean % CI" does not contain zero, indicating that if our statistical model is accurate, there is at least a 90.00% chance there is a difference in performance between baseline and comparison variants.
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Its configuration does not mark it "erratic".
CI Pass/Fail Decision
✅ Passed. All Quality Gates passed.
- quality_gate_idle_all_features, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
- quality_gate_idle_all_features, bounds check intake_connections: 10/10 replicas passed. Gate passed.
- quality_gate_idle_all_features, bounds check memory_usage: 10/10 replicas passed. Gate passed.
- quality_gate_security_idle, bounds check memory_usage: 10/10 replicas passed. Gate passed.
- quality_gate_security_idle, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
- quality_gate_security_no_fs_load, bounds check memory_usage: 10/10 replicas passed. Gate passed.
- quality_gate_security_no_fs_load, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
- quality_gate_metrics_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
- quality_gate_metrics_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
- quality_gate_metrics_logs, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
- quality_gate_metrics_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
- quality_gate_metrics_logs, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
- quality_gate_idle, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
- quality_gate_idle, bounds check memory_usage: 10/10 replicas passed. Gate passed.
- quality_gate_idle, bounds check intake_connections: 10/10 replicas passed. Gate passed.
- quality_gate_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
- quality_gate_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
- quality_gate_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
- quality_gate_logs, bounds check total_bytes_received: 10/10 replicas passed. Gate passed.
- quality_gate_private_action_runner, bounds check memory_usage: 10/10 replicas passed. Gate passed.
- quality_gate_security_mean_fs_load, bounds check memory_usage: 10/10 replicas passed. Gate passed.
- quality_gate_security_mean_fs_load, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
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What does this PR do?
Isolates the
pkg/trace/writertests from each other, and adds the diagnostics needed to identify the culprit if the flake recurs. Also fixes two sender shutdown bugs found while reading that path.Test isolation
cleanupWritergives every stats test ownership of its writer and its test server, stopping senders before closing the server. Bothsender.StopandtestServer.Closeare now idempotent so a test may still tear down explicitly.TestTraceWriterFlushSync/ok,TestResetBuffer,TestTraceWriterSyncNoop/ok,TestTraceWriterV1FlushSync/ok,TestTraceWriterV1ResetBuffer) and closes the test server inTestTraceWriterMultipleEndpointsConcurrent, the only listener intrace_test.goleft bound.TestMainnow fails an otherwise-green run that leaks sender goroutines. This is what found the five leaks above.Diagnostics
expectResponsesmarker — the one non-gzip body the package produces.assertPayload,payloadsContainandpayloadsContainV1assert how many requests arrived before decoding any, and print that provenance on failure. Two call sites whose counts are genuinely nondeterministic opt out via a documented-1sentinel.http.ErrAbortHandler.Sender fixes (the only non-test changes)
Pushcounted a payload as inflight after queuing it, soFlushSyncandStopcould observe zero while a payload was already queued and return before it was sent.Stopis idempotent and now waits for its worker goroutines, bounded by the same five second budget the inflight wait uses so a worker asleep in backoff cannot stall agent shutdown.Motivation
TestStatsSyncWriter/okfailed onmain(job 1995053897) withgzip: invalid header, alongside sevenuse of closed network connectionpanics from the test server. The same signature hitTestTraceWriterMultipleEndpointsConcurrentearlier (job 1977041561); #55406 only removed a follow-on nil deref, so the cause was never found. Earlier attempts (#44601, #42036) did not touch it either.gzip: invalid headermeans the first bytes were not1f 8b, so the recorded body was never a writer payload at all. The package's tests were not isolated:newSenderstartsConnectionLimitworker goroutines immediately, so a forgotten writer left workers, an HTTP client and a bound listener alive for every later test to interact with — and a closed listener's ephemeral port can be handed to a later test's server, at which point one test's requests land on another test's server and get recorded as its payloads. The only non-gzip bodies in the package are the plain-text onesexpectResponsesbuilds.Describe how you validated your changes
dda inv test --targets=./pkg/trace/writerand--race— 84 tests pass, no leaked goroutinesdda inv test --targets=./pkg/trace/...and--race— 1721 tests pass--race— all greendda inv linter.go --targets=./pkg/trace/writer— 0 issues;gofmtclean; gazelle produced no BUILD changesErrAbortHandlerbehaviour is covered byTestTestServer/truncated-body, verified to fail if that change is reverted (it reads backHTTP/1.1 400 Bad Request). An earlier version of that test passed against both behaviours and was rewritten.Additional Notes
Two points worth a reviewer's judgement rather than treating as settled:
ReadErrors()tripwire changes a failure mode. A straggler request that previously passed vacuously —assertPayloadnever checked the payload count — now fails the test. That is intentional, but on a loaded runner it could makeTestStatsSyncWriterfail more often, just with a message naming the cause instead ofgzip: invalid header.TestStatsSyncWriteris left in place. Removing it would be the real test of this fix; I did not want to gamble on macOS CI in the same PR.TestStatsSyncWriter/stoppreviously asserted nothing: in sync modeWriteonly buffers andStopdoes not flush, so zero payloads arrive, and the oldassertPayloadpassed vacuously. It now asserts that behaviour explicitly. WhetherStopshould flush pending sync-mode payloads is a separate question I have not answered here.Deliberately out of scope:
Stopcan stillclose(s.queue)under a producer blocked on a full queue once the five second wait expires (sender.go). Pre-existing; this PR makes it strictly less likely by counting inflight before the blocking send, but does not remove it. Wants its own fix.httptestlisteners — the listener is the actual port-reuse hazard. Fixed the one instance by hand; nothing prevents the next.waitTimeoutleaks its helper goroutine if the wait group never completes.🤖 Generated with Claude Code