fix(fpm): guard response reads and strip bridge headers#62
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sjinks
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Pull request overview
Adds an opt-in FastCGI (FPM) response timeout to prevent the runner from hanging indefinitely when the FPM bridge stalls, and aligns the devcontainer PHP bridge output to strip customer-emitted headers before returning the JSON envelope.
Changes:
- Introduces
-fpm-response-timeout(default0, disabled) and threads it into the CLI performer to bound FPM response handling. - Adds a unit test covering a hung FPM response path using a
gofast.ResponsePipethat never produces output. - Updates the devcontainer
fpm-cron-runner.phpbridge to remove all previously-set headers before sending the JSON response.
Reviewed changes
Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.
Show a summary per file
| File | Description |
|---|---|
| readme.md | Documents the new -fpm-response-timeout flag. |
| main.go | Adds CLI flag plumbing and passes the timeout into the performer. |
| performer/cli.go | Implements timeout-aware request creation + guarded response streaming. |
| performer/performer_test.go | Adds a focused timeout test for a hung FPM response. |
| .devcontainer/local-features/cron-runner-environment/fpm-cron-runner.php | Clears bridge-emitted headers before returning the JSON envelope. |
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…wording Addresses Copilot review comments on PR #62. ## What changed - Bump the FPM response timeout test from 10ms to 1s to avoid CI flake from goroutine scheduling jitter on shared runners. - Rename the timeout error wording from "response write timed out" to "response read timed out" so it reflects that the bound is on reading the FastCGI response stream (the in-memory `fakeHTTPResponseWriter` cannot block on writes), not on writing to a client. - Update the test assertion to match the new wording. ## Why - The 10ms threshold is below typical CI scheduler quanta; the test was fundamentally racy. - "Response write timed out" misled the on-call about which leg of the FPM bridge was stuck during the incident referenced by this PR.
robersongomes
approved these changes
Jun 5, 2026
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Summary
-fpm-response-timeoutflag that bounds the FPM response read/write phase and closes the response pipe on timeout.-fpm-response-timeout=0.fpm-cron-runner.phpbridge before returning the JSON envelope.Why
PLTFRM-2424 traced stuck Cron Control Runner behavior to long customer-emitted response headers reaching the FPM/gofast path before normal watcher startup. The production bridge cleanup is being handled in Automattic/wpvip-dockerfiles#493; this PR keeps the runner devcontainer bridge in parity and adds runner-side fail-fast hardening for future FPM response stalls.
Validation
php -l .devcontainer/local-features/cron-runner-environment/fpm-cron-runner.phpgo test ./...git diff --checkContent-Security-Policyheader returned onlyContent-Type: application/jsonand a valid{ "buf", "stdout", "stderr" }JSON envelope.Notes