feat: add github actions and dockerfile (#16)

.github/workflows/build.yaml

@@ -0,0 +1,61 @@
+name: Build
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  build-and-push-image:
+    name: Build and Push Docker images
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - uses: dorny/paths-filter@v3
+        id: changes
+        with:
+          filters: |
+            dockerfile:
+              - 'Dockerfile'
+
+      - if: steps.changes.outputs.dockerfile == 'true'
+        name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+
+      - if: steps.changes.outputs.dockerfile == 'true'
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - if: steps.changes.outputs.dockerfile == 'true'
+        name: Login to GitHub Container Registry
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      # GHCR requires lowercase.
+      - if: steps.changes.outputs.dockerfile == 'true'
+        id: repo-lower
+        uses: ASzc/change-string-case-action@v5
+        with:
+          string: ${{ github.repository }}
+
+      - if: steps.changes.outputs.dockerfile == 'true'
+        uses: benjlevesque/[email protected]
+        id: short-sha
+        with:
+          length: 7
+
+      - if: steps.changes.outputs.dockerfile == 'true'
+        name: Build and push
+        uses: docker/build-push-action@v4
+        with:
+          push: true
+          platforms: linux/amd64,linux/arm64
+          tags: ghcr.io/${{ steps.repo-lower.outputs.lowercase }}:${{ steps.short-sha.outputs.sha }}, ghcr.io/${{ steps.repo-lower.outputs.lowercase }}:latest

Dockerfile

@@ -0,0 +1 @@
+FROM quay.io/akuity/argo-cd-learning-assets/guestbook:latest