CI Build Cache Advisor#

Optimize CI/CD build caching strategies across GitHub Actions, GitLab CI, CircleCI, and Jenkins. Analyze cache configurations, recommend cache keys, identify cache misses, and reduce build times by maximizing cache hit rates.

Usage#

text

"Optimize caching in my CI pipeline"
"Why are my builds not using cache?"
"Design cache keys for my monorepo CI"
"Reduce my CI build time"

How It Works#

1. CI Platform Detection#

bash

ls .github/workflows/ 2>/dev/null && echo "GitHub Actions"
ls .gitlab-ci.yml 2>/dev/null && echo "GitLab CI"
ls .circleci/config.yml 2>/dev/null && echo "CircleCI"
ls Jenkinsfile 2>/dev/null && echo "Jenkins"

2. Cache Analysis#

What should be cached:

• Package manager dependencies (node_modules, .pip, .cargo, .gradle)
• Build artifacts (compiled code, generated assets)
• Docker layers
• Test fixtures and snapshots
• Linter and type checker caches

Cache key strategy:

• Primary key: hash of lockfile (package-lock.json, Cargo.lock)
• Restore key: platform + branch fallback
• Matrix-aware: different caches per OS/Node version/Python version
• Monorepo: workspace-specific caches

3. Common Issues#

• Cache too broad: Single cache for entire node_modules invalidated by any dep change
• Cache too narrow: Cache key includes commit SHA (never hits)
• Missing restore keys: No fallback when primary key misses
• Cache pollution: Dev dependencies cached for production builds
• Stale cache: Cache never expires, using outdated artifacts
• Cache size limit: Exceeding platform limits (GitHub: 10GB, GitLab: varies)

4. Recommendations by Platform#

GitHub Actions:

yaml

- uses: actions/cache@v4
  with:
    path: ~/.npm
    key: ${{ runner.os }}-npm-${{ hashFiles('**/package-lock.json') }}
    restore-keys: |
      ${{ runner.os }}-npm-

GitLab CI:

yaml

cache:
  key:
    files: [package-lock.json]
    prefix: $CI_JOB_NAME
  paths: [node_modules/]
  policy: pull-push

5. Advanced Strategies#

• Turbo/Nx remote caching: Share build cache across CI and developers
• Docker layer caching: BuildKit cache mounts, registry-backed cache
• Gradle build cache: Remote cache server for team-wide sharing
• ccache/sccache: C/C++/Rust compilation caching

Output#

text

## CI Cache Optimization

**Platform:** GitHub Actions | **Workflows:** 3

### Current Cache Usage
| Workflow | Cache Configured | Hit Rate | Build Time |
|----------|-----------------|----------|------------|
| CI | Yes (npm) | 67% | 8m 30s |
| Deploy | No | 0% | 12m 15s |
| Release | Partial | 45% | 15m |

### Recommendations
1. **Add npm cache to Deploy workflow** — saves ~3 min/run
2. **Fix CI cache key** — includes branch name (low hit rate on PRs)
   → Remove branch, use lockfile hash only
3. **Add Docker layer caching to Release** — saves ~5 min
4. **Add TypeScript build cache** — `tsBuildInfoFile` not cached

### Projected Improvement
- CI: 8m 30s → 3m 45s (56% faster)
- Deploy: 12m 15s → 7m (43% faster)
- Release: 15m → 8m (47% faster)
- Monthly minutes saved: ~2,400 (~$19)