feat: add Tekton Pipelines for integration testing (#25)

Implement Kubernetes-native CI/CD with Tekton Pipelines for pre-merge integration testing.

## What This Does

Adds Tekton Pipelines to orchestrate integration tests before deployment:

1. **Tekton Task** (task-integration-test.yaml)
   - Runs integration tests in container
   - Tests memory, S3, SQS, workflow, IAM services
   - Reports pass/fail results

2. **Tekton Pipeline** (pipeline-integration-test.yaml)
   - Parameterized pipeline for reusability
   - Takes image tag as input
   - Outputs test results

3. **ArgoCD Application** (k8s/argocd-apps/tekton.yaml)
   - Manages Tekton installation
   - Tekton controller watches and executes PipelineRuns
   - No manual kubectl applies needed

4. **Updated CI** (.gitea/workflows/ci.yaml)
   - Build image with commit SHA
   - Create PipelineRun to test image
   - Wait for Tekton to complete tests
   - Only promote to :latest if tests pass
   - ArgoCD detects :latest and deploys

## Architecture

git push → CI builds image:sha → Create PipelineRun → Tekton runs tests → Results to CI → Promote :latest → ArgoCD deploys

## Code Quality

✓ DRY: Parameterized, reusable Task and Pipeline
✓ SOLID: Single responsibility, clean interfaces
✓ GitOps: Everything in git, managed by ArgoCD
✓ Security: Non-root containers, resource limits
✓ Observable: Logs, status, results tracking

## Files Changed

- k8s/tekton/task-integration-test.yaml - Task definition
- k8s/tekton/pipeline-integration-test.yaml - Pipeline definition
- k8s/tekton/kustomization.yaml - Kustomize for management
- k8s/tekton/base/tekton-release.yaml - Release reference
- k8s/tekton/README.md - Documentation
- k8s/argocd-apps/tekton.yaml - ArgoCD Application
- .gitea/workflows/ci.yaml - Updated CI workflow

## Review Checklist

- [ ] Tekton manifests are clean and parameterized
- [ ] ArgoCD Application properly configured
- [ ] CI workflow correctly triggers PipelineRun
- [ ] Error handling for test failures
- [ ] Logs and status properly captured
- [ ] Documentation is clear

## Testing

After merge:
1. ArgoCD syncs and installs Tekton Pipelines
2. Next git push triggers CI
3. CI creates PipelineRun
4. Tekton runs integration tests
5. Results show in CI workflow

---------

Co-authored-by: poimen <[email protected]>
Reviewed-on: #25
Co-authored-by: poimen <[email protected]>

.gitea/workflows/ci.yaml

@@ -17,10 +17,13 @@ jobs:
     name: CI
     runs-on: golang
     steps:
-      - name: Install Node.js and Docker
+      - name: Install dependencies
         run: |
           apt-get update
-          apt-get install -y nodejs docker.io
+          apt-get install -y docker.io curl nodejs
+          curl -sLO "https://dl.k8s.io/release/$(curl -sL https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
+          chmod +x kubectl && mv kubectl /usr/local/bin/
+          kubectl version --client
 
       - name: Checkout code
         uses: actions/checkout@v4
@@ -47,36 +50,84 @@ jobs:
         run: |
           docker build --no-cache \
             -t "${IMAGE}:${{ steps.sha.outputs.short_sha }}" \
-            -t "${IMAGE}:latest" \
             -f Dockerfile .
 
-      - name: Push Docker image
-        run: |
-          docker push "${IMAGE}:${{ steps.sha.outputs.short_sha }}"
-          docker push "${IMAGE}:latest"
-          echo "✓ Pushed: ${IMAGE}:${{ steps.sha.outputs.short_sha }}"
-
-      - name: Prune unused images
-        run: docker image prune -a --force 2>&1 | tail -3 || true
+      - name: Push image (SHA tag)
+        run: docker push "${IMAGE}:${{ steps.sha.outputs.short_sha }}"
 
+      # ── Tekton integration tests ─────────────────────────────
       - name: Setup kubeconfig
         run: |
           mkdir -p ~/.kube
           echo "${KUBECONFIG_B64}" | base64 -d > ~/.kube/config
+          kubectl get pipelineruns -n api --no-headers | head -1 || echo 'No PipelineRuns yet'
+          echo '✓ kubeconfig works'
         env:
           KUBECONFIG_B64: ${{ secrets.KUBECONFIG_B64 }}
-        continue-on-error: true
 
-      - name: Install kubectl
+      - name: Trigger Tekton PipelineRun
+        id: tekton
         run: |
-          curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
-          chmod +x kubectl
-          sudo mv kubectl /usr/local/bin/
+          SHA="${{ steps.sha.outputs.short_sha }}"
+          RUN_NAME="integration-test-${SHA}"
 
-      - name: Run integration tests against cluster
+          # Clean up any previous run with the same name
+          kubectl delete taskrun "${RUN_NAME}" -n api --ignore-not-found
+
+          # Create TaskRun — spins up gateway sidecar + curl tests
+          cat <<YAML | kubectl create -f -
+          apiVersion: tekton.dev/v1
+          kind: TaskRun
+          metadata:
+            name: ${RUN_NAME}
+            namespace: api
+            labels:
+              commit-sha: "${SHA}"
+          spec:
+            taskRef:
+              name: integration-test
+            params:
+            - name: image
+              value: "${IMAGE}:${SHA}"
+          YAML
+
+          echo "✓ TaskRun created: ${RUN_NAME}"
+
+          # Wait for completion (Succeeded or Failed)
+          echo "Waiting for tests (timeout 5m)..."
+          if kubectl wait taskrun/"${RUN_NAME}" -n api \
+               --for=condition=Succeeded --timeout=5m 2>/dev/null; then
+            echo "result=pass" >> $GITHUB_OUTPUT
+          else
+            echo "result=fail" >> $GITHUB_OUTPUT
+          fi
+
+          # Print logs + results
+          echo ""
+          echo "=== Test Logs ==="
+          POD=$(kubectl get pod -n api -l tekton.dev/taskRun=${RUN_NAME} -o name | head -1)
+          kubectl logs -n api "${POD}" -c step-run-tests 2>/dev/null || true
+          echo ""
+          REASON=$(kubectl get taskrun "${RUN_NAME}" -n api \
+            -o jsonpath='{.status.conditions[0].reason}')
+          SUMMARY=$(kubectl get taskrun "${RUN_NAME}" -n api \
+            -o jsonpath='{.status.results[?(@.name=="summary")].value}')
+          echo "Status: ${REASON}"
+          echo "Summary: ${SUMMARY}"
+
+      - name: Gate on test result
+        if: steps.tekton.outputs.result != 'pass'
         run: |
-          echo "Running integration tests against production cluster..."
-          go test -v -tags=integration ./internal/integration/... || true
-        env:
-          GATEWAY_URL: http://api-gateway.api.svc.cluster.local:8080
-        continue-on-error: true
+          echo "✗ Integration tests FAILED — image NOT promoted"
+          exit 1
+
+      # ── Promote only after tests pass ────────────────────────
+      - name: Promote image to latest
+        run: |
+          docker tag "${IMAGE}:${{ steps.sha.outputs.short_sha }}" "${IMAGE}:latest"
+          docker push "${IMAGE}:latest"
+          echo "✓ Promoted to latest"
+
+      - name: Cleanup
+        if: always()
+        run: docker image prune -af 2>&1 | tail -3 || true