Publish Events via the Outbox Pattern

Write the event to an outbox table in the same transaction as the business write so the event is not lost if the broker is down.

~25 minapioutboxevents

Task

Implement INSERT INTO outbox (event_type, payload) VALUES ('order.created', $1); -- same tx as INSERT INTO orders so the service degrades gracefully under failure instead of cascading timeouts to callers.

When to use this

A downstream service slows down and without INSERT INTO outbox (event_type, payload) VALUES ('order.created', $1); -- same tx as INSERT INTO orders the upstream exhausts its thread pool in 12 seconds.

Prerequisites

A service with inter-service calls or external dependencies
A retry or circuit breaker library available

Steps

1. Configure INSERT INTO outbox (event_type, payload) VALUES ('order.created', $1); -- same tx as INSERT INTO orders in the project configuration file with the recommended defaults.

INSERT INTO outbox (event_type, payload) VALUES ('order.created', $1); -- same tx as INSERT INTO orders

Expected output: The configuration is accepted and INSERT INTO outbox (event_type, payload) VALUES ('order.created', $1); -- same tx as INSERT INTO orders runs without errors on the first invocation.

2. Run the check locally to verify INSERT INTO outbox (event_type, payload) VALUES ('order.created', $1); -- same tx as INSERT INTO orders produces the expected result before pushing.

pnpm test

Expected output: Local run matches CI behavior; no surprises after push.

3. Add the gate to the CI pipeline so INSERT INTO outbox (event_type, payload) VALUES ('order.created', $1); -- same tx as INSERT INTO orders blocks merge on failure.

- name: Run add outbox event publish
  run: pnpm test

Expected output: Pull requests with failing INSERT INTO outbox (event_type, payload) VALUES ('order.created', $1); -- same tx as INSERT INTO orders are blocked from merging.

Troubleshooting

Problem

The check passes locally but fails in CI

Solution

Pin dependency versions and the runtime to match CI exactly; reproduce with the same Docker image or act.

Problem

Configuration is rejected with a schema error

Solution

Check the tool version matches the config schema; older versions may not support newer fields.

Limitations

The gate only runs on events that trigger the workflow; locally pushed commits bypass it.
Configuration drift is possible if someone edits settings outside version control.

Isolate failure

Start by measuring the problem. Write the event to an outbox table in the same transaction as the business write so the event is not lost if the broker is down. The most common mistake is adding the gate without first confirming it catches the issue you care about. Run INSERT INTO outbox (event_type, payload) VALUES (‘order.created’, $1); – same tx as INSERT INTO orders against the current codebase and inspect the output before wiring it into CI.

INSERT INTO outbox (event_type, payload) VALUES ('order.created', $1); -- same tx as INSERT INTO orders

Verify graceful degradation

Once the gate is in place, make failures actionable. A failing INSERT INTO outbox (event_type, payload) VALUES (‘order.created’, $1); – same tx as INSERT INTO orders should point to the exact file and line, not a generic error. Pin the tool version in the lockfile so a upstream release does not silently change behavior. Review the gate output in every pull request just like a test result.