1.4. Reflection Checkpoint

Key Takeaways

• Memorize the chain: event → workflow → job(s) → steps → runner, and decompose every scenario question into which link it tests.
• Jobs are isolated on fresh, disposable VMs — state never survives implicitly; it must be passed via artifacts, outputs, or caches.
• Triggers are the control surface of automation: event choice, activity types, and branch/path filters determine when (and whether) anything runs — with schedules in UTC from the default branch only.
• Reuse exists at three granularities — composite actions (steps), reusable workflows (jobs/pipelines), starter workflows (one-time scaffolds) — and they are not interchangeable.

Connecting Forward

Phase 2 turns each link of the chain into exam-grade detail: the full trigger vocabulary (including workflow_dispatch inputs and workflow_call secret mapping), job orchestration with needs: and conditionals, matrices, service containers, YAML anchors, contexts and expressions, and the artifact/cache/output machinery that moves data through a run.

Self-Check Questions

• A question describes a workflow that "ran on a schedule but used stale code from the wrong branch." Which two properties of schedule: explain the behavior?
• Without looking ahead: why must actions/checkout be the first real step of nearly every job, and what does that tell you about the runner contract?
• Name the three reuse mechanisms and, for each, the moment at which the consumer's copy of the logic is fixed: authoring time, creation time, or call time?