# Docker CI/CD Optimization: Phase 2-3 Implementation Complete

**Date:** February 4, 2026
**Phase:** 2-3 (Integration Workflow Migration)
**Status:** ✅ Complete - Ready for Testing

---

## Executive Summary

Successfully migrated 4 integration test workflows to use the registry image from `docker-build.yml` instead of building their own images. This eliminates **~40 minutes of redundant build time per PR**.

### Workflows Migrated

1. ✅ `.github/workflows/crowdsec-integration.yml`
2. ✅ `.github/workflows/cerberus-integration.yml`
3. ✅ `.github/workflows/waf-integration.yml`
4. ✅ `.github/workflows/rate-limit-integration.yml`

---

## Implementation Details

### Changes Applied (Per Section 4.2 of Spec)

#### 1. **Trigger Mechanism** ✅
- **Added:** `workflow_run` trigger waiting for "Docker Build, Publish & Test"
- **Added:** Explicit branch filters: `[main, development, 'feature/**']`
- **Added:** `workflow_dispatch` for manual testing with optional tag input
- **Removed:** Direct `push` and `pull_request` triggers

**Before:**
```yaml
on:
  push:
    branches: [ main, development, 'feature/**' ]
  pull_request:
    branches: [ main, development ]
```

**After:**
```yaml
on:
  workflow_run:
    workflows: ["Docker Build, Publish & Test"]
    types: [completed]
    branches: [main, development, 'feature/**']
  workflow_dispatch:
    inputs:
      image_tag:
        description: 'Docker image tag to test'
        required: false
```

#### 2. **Conditional Execution** ✅
- **Added:** Job-level conditional: only run if docker-build.yml succeeded
- **Added:** Support for manual dispatch override

```yaml
if: ${{ github.event.workflow_run.conclusion == 'success' || github.event_name == 'workflow_dispatch' }}
```

#### 3. **Concurrency Controls** ✅
- **Added:** Concurrency groups using branch + SHA
- **Added:** `cancel-in-progress: true` to prevent race conditions
- **Handles:** PR updates mid-test (old runs auto-canceled)

```yaml
concurrency:
  group: ${{ github.workflow }}-${{ github.event.workflow_run.head_branch || github.ref }}-${{ github.event.workflow_run.head_sha || github.sha }}
  cancel-in-progress: true
```

#### 4. **Image Tag Determination** ✅
- **Uses:** Native `github.event.workflow_run.pull_requests` array (NO API calls)
- **Handles:** PR events → `pr-{number}-{sha}`
- **Handles:** Branch push events → `{sanitized-branch}-{sha}`
- **Applies:** Tag sanitization (lowercase, replace `/` with `-`, remove special chars)
- **Validates:** PR number extraction with comprehensive error handling

**PR Tag Example:**
```
PR #123 with commit abc1234 → pr-123-abc1234
```

**Branch Tag Example:**
```
feature/Add_New-Feature with commit def5678 → feature-add-new-feature-def5678
```

#### 5. **Registry Pull with Retry** ✅
- **Uses:** `nick-fields/retry@v3` action
- **Configuration:**
  - Timeout: 5 minutes
  - Max attempts: 3
  - Retry wait: 10 seconds
- **Pulls from:** `ghcr.io/wikid82/charon:{tag}`
- **Tags as:** `charon:local` for test scripts

```yaml
- name: Pull Docker image from registry
  id: pull_image
  uses: nick-fields/retry@v3
  with:
    timeout_minutes: 5
    max_attempts: 3
    retry_wait_seconds: 10
    command: |
      IMAGE_NAME="ghcr.io/${{ github.repository_owner }}/charon:${{ steps.image.outputs.tag }}"
      docker pull "$IMAGE_NAME"
      docker tag "$IMAGE_NAME" charon:local
```

#### 6. **Dual-Source Fallback Strategy** ✅
- **Primary:** Registry pull (fast, network-optimized)
- **Fallback:** Artifact download (if registry fails)
- **Handles:** Both PR and branch artifacts
- **Logs:** Which source was used for troubleshooting

**Fallback Logic:**
```yaml
- name: Fallback to artifact download
  if: steps.pull_image.outcome == 'failure'
  run: |
    # Determine artifact name (pr-image-{N} or push-image)
    gh run download ${{ github.event.workflow_run.id }} --name "$ARTIFACT_NAME"
    docker load < /tmp/docker-image/charon-image.tar
    docker tag $(docker images --format "{{.Repository}}:{{.Tag}}" | head -1) charon:local
```

#### 7. **Image Freshness Validation** ✅
- **Checks:** Image label SHA matches expected commit SHA
- **Warns:** If mismatch detected (stale image)
- **Logs:** Both expected and actual SHA for debugging

```yaml
- name: Validate image SHA
  run: |
    LABEL_SHA=$(docker inspect charon:local --format '{{index .Config.Labels "org.opencontainers.image.revision"}}' | cut -c1-7)
    if [[ "$LABEL_SHA" != "$SHA" ]]; then
      echo "⚠️ WARNING: Image SHA mismatch!"
    fi
```

#### 8. **Build Steps Removed** ✅
- **Removed:** `docker/setup-buildx-action` step
- **Removed:** `docker build` command (~10 minutes per workflow)
- **Kept:** All test execution logic unchanged
- **Result:** ~40 minutes saved per PR (4 workflows × 10 min each)

---

## Testing Checklist

Before merging to main, verify:

### Manual Testing

- [ ] **PR from feature branch:**
  - Open test PR with trivial change
  - Wait for docker-build.yml to complete
  - Verify all 4 integration workflows trigger
  - Confirm image tag format: `pr-{N}-{sha}`
  - Check workflows use registry image (no build step)

- [ ] **Push to development branch:**
  - Push to development branch
  - Wait for docker-build.yml to complete
  - Verify integration workflows trigger
  - Confirm image tag format: `development-{sha}`

- [ ] **Manual dispatch:**
  - Trigger each workflow manually via Actions UI
  - Test with explicit tag (e.g., `latest`)
  - Test without tag (defaults to `latest`)

- [ ] **Concurrency cancellation:**
  - Open PR with commit A
  - Wait for workflows to start
  - Force-push commit B to same PR
  - Verify old workflows are canceled

- [ ] **Artifact fallback:**
  - Simulate registry failure (incorrect tag)
  - Verify workflows fall back to artifact download
  - Confirm tests still pass

### Automated Validation

- [ ] **Build time reduction:**
  - Compare PR build times before/after
  - Expected: ~40 minutes saved (4 × 10 min builds eliminated)
  - Verify in GitHub Actions logs

- [ ] **Image SHA validation:**
  - Check workflow logs for "Image SHA matches expected commit"
  - Verify no stale images used

- [ ] **Registry usage:**
  - Confirm no `docker build` commands in logs
  - Verify `docker pull ghcr.io/wikid82/charon:*` instead

---

## Rollback Plan

If issues are detected:

### Partial Rollback (Single Workflow)
```bash
# Restore specific workflow from git history
git checkout HEAD~1 -- .github/workflows/crowdsec-integration.yml
git commit -m "Rollback: crowdsec-integration to pre-migration state"
git push
```

### Full Rollback (All Workflows)
```bash
# Create rollback branch
git checkout -b rollback/integration-workflows

# Revert migration commit
git revert HEAD --no-edit

# Push to main
git push origin rollback/integration-workflows:main
```

**Time to rollback:** ~5 minutes per workflow

---

## Expected Benefits

### Build Time Reduction
| Metric | Before | After | Improvement |
|--------|--------|-------|-------------|
| Builds per PR | 5x (1 main + 4 integration) | 1x (main only) | **5x reduction** |
| Build time per workflow | ~10 min | 0 min (pull only) | **100% saved** |
| Total redundant time | ~40 min | 0 min | **40 min saved** |
| CI resource usage | 5x parallel builds | 1 build + 4 pulls | **80% reduction** |

### Consistency Improvements
- ✅ All tests use **identical image** (no "works on my build" issues)
- ✅ Tests always use **latest successful build** (no stale code)
- ✅ Race conditions prevented via **immutable tags with SHA**
- ✅ Build failures isolated to **docker-build.yml** (easier debugging)

---

## Next Steps

### Immediate (Phase 3 Complete)
1. ✅ Merge this implementation to feature branch
2. 🔄 Test with real PRs (see Testing Checklist)
3. 🔄 Monitor for 1 week on development branch
4. 🔄 Merge to main after validation

### Phase 4 (Week 6)
- Migrate `e2e-tests.yml` workflow
- Remove build job from E2E workflow
- Apply same pattern (workflow_run + registry pull)

### Phase 5 (Week 7)
- Enhance `container-prune.yml` for PR image cleanup
- Add retention policies (24h for PR images)
- Implement "in-use" detection

---

## Metrics to Monitor

Track these metrics post-deployment:

| Metric | Target | How to Measure |
|--------|--------|----------------|
| Average PR build time | <20 min (vs 62 min before) | GitHub Actions insights |
| Image pull success rate | >95% | Workflow logs |
| Artifact fallback rate | <5% | Grep logs for "falling back" |
| Test failure rate | <5% (no regression) | GitHub Actions insights |
| Workflow trigger accuracy | 100% (no missed triggers) | Manual verification |

---

## Documentation Updates Required

- [ ] Update `CONTRIBUTING.md` with new workflow behavior
- [ ] Update `docs/ci-cd.md` with architecture diagrams
- [ ] Create troubleshooting guide for integration tests
- [ ] Update PR template with CI/CD expectations

---

## Known Limitations

1. **Requires docker-build.yml to succeed first**
   - Integration tests won't run if build fails
   - This is intentional (fail fast)

2. **Manual dispatch requires knowing image tag**
   - Use `latest` for quick testing
   - Use `pr-{N}-{sha}` for specific PR testing

3. **Registry must be accessible**
   - If GHCR is down, workflows fall back to artifacts
   - Artifact fallback adds ~30 seconds

---

## Success Criteria Met

✅ **All 4 workflows migrated** (`crowdsec`, `cerberus`, `waf`, `rate-limit`)
✅ **No redundant builds** (verified by removing build steps)
✅ **workflow_run trigger** with explicit branch filters
✅ **Conditional execution** (only if docker-build.yml succeeds)
✅ **Image tag determination** using native context (no API calls)
✅ **Tag sanitization** for feature branches
✅ **Retry logic** for registry pulls (3 attempts)
✅ **Dual-source strategy** (registry + artifact fallback)
✅ **Concurrency controls** (race condition prevention)
✅ **Image SHA validation** (freshness check)
✅ **Comprehensive error handling** (clear error messages)
✅ **All test logic preserved** (only image sourcing changed)

---

## Questions & Support

- **Spec Reference:** `docs/plans/current_spec.md` (Section 4.2)
- **Implementation:** Section 4.2 requirements fully met
- **Testing:** See "Testing Checklist" above
- **Issues:** Check Docker build logs first, then integration workflow logs

---

## Approval

**Ready for Phase 4 (E2E Migration):** ✅ Yes, after 1 week validation period

**Estimated Time Savings per PR:** 40 minutes
**Estimated Resource Savings:** 80% reduction in parallel build compute
