Reusable Workflows & Composite Actions

DRY workflow patterns, composite actions, and workflow composition

Language / Topic

GitHub Actions

Rules

Reusable Workflows & Composite Actions · balanced balanced

- Create reusable workflows (workflow_call trigger) for shared CI/CD patterns across repositories

- Use composite actions for reusable step sequences within a single job (e.g., setup + build + cache)

- Define clear input/output contracts: use inputs with descriptions and required flags

- Store reusable workflows in a central .github repository for organization-wide sharing

- Prefer reusable workflows over duplicated workflow YAML across repositories

- Reusable workflows (on: workflow_call): shared CI/CD pipelines called from other workflows with inputs/secrets

- Composite actions (action.yml with using: composite): reusable step groups for setup, build, deploy patterns

- Clear contracts: define inputs (descriptions, required, defaults), outputs, and secrets on all reusable components

- Central repository: .github org repo or dedicated actions-* repos for organization-wide workflow sharing

- Reusable > copy-paste: one workflow definition, called from all repos, updates propagate automatically

- Version reusable workflows with tags: uses: org/.github/.github/workflows/ci.yml@v2 for stability

- Pass secrets explicitly: secrets: inherit or named secrets mapping — never rely on ambient secret access

- Composite actions for complex setup: checkout + cache + install + build as one action with clear outputs

- Use strategy matrices in caller workflows for variation (OS, language version) while keeping pipeline DRY

- Document reusable workflows with README, example caller workflow, and input/output specification