ci: add github actions pipeline for build, push, and manifest update

Author: moabdelazem

.github/workflows/ci.yaml

@@ -0,0 +1,67 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+
+env:
+  DOCKER_IMAGE: moabdelazem/gitops-app
+  MANIFESTS_REPO: moabdelazem/gitops-sample-app-manifests
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set build metadata
+        id: meta
+        run: |
+          echo "VERSION=${GITHUB_SHA::7}" >> $GITHUB_OUTPUT
+          echo "GIT_COMMIT=${GITHUB_SHA::7}" >> $GITHUB_OUTPUT
+          echo "BUILD_TIME=$(date -u '+%Y-%m-%dT%H:%M:%SZ')" >> $GITHUB_OUTPUT
+
+      - name: Login to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: true
+          build-args: |
+            VERSION=${{ steps.meta.outputs.VERSION }}
+            GIT_COMMIT=${{ steps.meta.outputs.GIT_COMMIT }}
+            BUILD_TIME=${{ steps.meta.outputs.BUILD_TIME }}
+          tags: |
+            ${{ env.DOCKER_IMAGE }}:${{ steps.meta.outputs.VERSION }}
+            ${{ env.DOCKER_IMAGE }}:latest
+
+  update-manifests:
+    runs-on: ubuntu-latest
+    needs: build-and-push
+
+    steps:
+      - name: Checkout manifests repo
+        uses: actions/checkout@v4
+        with:
+          repository: ${{ env.MANIFESTS_REPO }}
+          token: ${{ secrets.MANIFESTS_PAT }}
+
+      - name: Update dev overlay image tag
+        run: |
+          cd overlays/dev
+          sed -i "s|newTag:.*|newTag: ${GITHUB_SHA::7}|" kustomization.yaml
+
+      - name: Commit and push
+        run: |
+          git config user.name "github-actions"
+          git config user.email "github-actions@github.com"
+          git add .
+          git commit -m "chore: update dev image to ${GITHUB_SHA::7}"
+          git push