Pull Request Pipeline

Gate failure cancellation

E2E steps (FTR, Scout, Cypress) start as soon as build completes. If a gate step (linting, type checks, etc.) fails, registered E2E steps are automatically canceled to minimize cost from running expensive jobs when there are obvious failures.

How it works

1. Gate steps in base.yml are tagged with env: { CHECK_GATE: 'true' }.
2. E2E steps are registered at pipeline upload time by passing { cancelOnGateFailure: true } to getPipeline(), or by writing a single batch metadata key (e.g. cancel_on_gate_failure_batch:<namespace>) containing a JSON array of step keys.
3. When a gate step fails permanently, post_command.sh runs scripts/steps/gate_failure/cancel.ts, which reads cancel_on_gate_failure_batch:* metadata keys (each containing a JSON array of step keys) and cancels those steps.

Important: step cancel does not work on group keys

buildkite-agent step cancel only cancels individual command steps. It silently fails on group keys (e.g., ftr-configs, scout-configs). Always register child step keys for cancellation, not the parent group key.

Adding a new cancelable step

• Static YAML pipeline: Add a key: to every command step in the YAML file, then pass { cancelOnGateFailure: true } to getPipeline(). If a step is a group, extractStepKeys() will automatically recurse into its children and register their keys instead. Missing keys on command steps will cause a build-time error.
• Dynamic step uploader: Add a key to each child step in bk.uploadSteps(), then register all child keys in a single batch metadata write:
  tsCopy

  bk.setMetadata(
    'cancel_on_gate_failure_batch:<namespace>',
    JSON.stringify(childSteps.map(s => s.key))
  );
  

  Do not register the group key — it will silently fail to cancel.