[scott-lowe-vapi]

Support partial GitOps promotions using traffic splitting

Part of DEPLOY-205. 3 of 5: the ticker that moves ramps forward, and the workflows that run it.

What changes

• npm run rollout -- advance|abort|status (src/rollout-cmd.ts; decisions in src/rollout-tick.ts, pure):
  • A step whose interval has passed moves to the next step.
  • The last step is an explicit 100%. The next tick hands back to follow-latest, or holds if a newer, un-ramped version was published meanwhile, because follow-latest would send that version every call.
  • A pin older than 6h (the promotion step's cap is 330 min, and a test ties the two) is adopted if its run published, released if it replaced the default, and otherwise flagged.
  • Any split changed by someone else stops that ramp.
  • An abort is retried once on a race.
• .github/workflows/rollout.yml:
  • cron every 15 min, behind VAPI_ROLLOUT_ENABLED; dispatch always runs;
  • its own vapi-rollout concurrency group, never vapi-promotion, so a tick can't cancel a pending promotion;
  • a dispatched abort gets a group of its own;
  • timeout-minutes: 15, read-only, commits nothing.
• promotion.yml gains a rollout dispatch input (default, no-rollout, override; override needs pipeline/from/to). Push-triggered runs are unchanged.
• Docs: the rollout workflow in docs/guides/promotion.md, npm run rollout in commands.md and the README, and the per-write labels in how-it-works.md.

Evidence

• tests/rollout-tick.test.ts covers every row of the decision table, including the killed-before-publish pins over an abort, a hold and an override, which are not adopted.
• tests/rollout-cmd.test.ts covers advance, a foreign change, an idempotent 409, the probe skip, abort and its race, and status.
• tests/rollout-workflow.test.ts runs both workflows' real shell steps with an npm stub, plus the 6h-vs-330-min check.

672 tests pass. actionlint runs in CI; I didn't run it locally.

🤖 Generated with Claude Code

[scott-lowe-vapi]

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Learn more

• feat(rollout): report each tick's ramps and fail the run when one is overdue #90
• feat(rollout): gate each ramp step on the new version's calls and errors #89
• feat(rollout): add the rollout ticker, its workflow and promotion's rollout input #88 👈 (View in Graphite)
• feat(promote): pin assistants around the apply so a rollout org ramps instead of cutting over #87
• feat(promote): add rollout config, traffic-allocation client and splitting probe #86
• main

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