ready-gate

Readiness gate

Hold a dependent service until a check passes. ready-check blocks the start of dependents until the named check reports healthy.

Config

# Readiness gate: hold a dependent until a check passes.
processes:
  - name: db
    command: /usr/local/bin/db
    args: ["300"]
    on-failure: shutdown

  - name: app
    command: /usr/local/bin/app
    args: ["300"]
    after: [db]
    ready-check: db-ready
    ready-timeout: 10s
    on-failure: shutdown

checks:
  db-ready:
    exec:
      command: /bin/true
      args: []
    period: 300ms
    threshold: 1
    level: ready

• after: [db] orders app to start after db.
• ready-check: db-ready gates app: it does not start until the db-ready check passes.
• ready-timeout bounds the wait; if the check never passes, gopherd exits non-zero.
• level: ready marks the check as a readiness gate (vs. an ongoing liveness probe).

Expected behavior

• gopherd starts db, then runs the db-ready check.
• app stays unstarted until db-ready reports healthy, then starts.
• Both report running once the gate opens. A failing check that never passes trips ready-timeout and gopherd exits non-zero.

Test

Run level. The test substitutes /usr/bin/sleep for both db and app. Because app carries a ready-check gate, a running app proves the gate opened after db-ready passed; the test asserts both db and app are running, then a clean SIGTERM exit 0.

The ready-timeout path (a check that never passes) is asserted in the root e2e suite (TestE2EReadyCheckTimeout).

go test ./documentation/ready-gate/ -v