feat: build docker image w/ GHA

.github/workflows/on-pull-request.yaml

@@ -0,0 +1,12 @@
+name: On Pull Request
+
+on:
+  pull_request:
+
+jobs:
+  build:
+    name: Build
+    uses: ./.github/workflows/wf-docker-build.yaml
+    with:
+      push-ghcr: true
+      save-cache: true

.github/workflows/on-push-main.yaml

@@ -0,0 +1,13 @@
+name: On Push Main
+
+on:
+  push:
+    branches: [main]
+
+jobs:
+  build:
+    name: Build
+    uses: ./.github/workflows/wf-docker-build.yaml
+    with:
+      push-ghcr: false
+      save-cache: false

.github/workflows/wf-docker-build.yaml

@@ -0,0 +1,55 @@
+name: Build Docker Images
+
+on:
+  workflow_call:
+    inputs:
+      push-ghcr:
+        type: boolean
+        default: false
+      save-cache:
+        type: boolean
+        default: false
+
+jobs:
+  build_and_push:
+    name: Build and Push
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    steps:
+      - uses: actions/checkout@v4
+      - uses: docker/setup-buildx-action@v3
+      - uses: docker/setup-qemu-action@v3
+
+      - if: inputs.push-ghcr
+        name: Login to ghcr.io
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Docker Metadata
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: |
+            ${{ inputs.push-ghcr && format('ghcr.io/{0}', github.repository) || '' }}
+          tags: |
+            type=raw,value=latest,enable={{is_default_branch}}
+            type=ref,event=pr
+            type=sha
+      - name: Build and Push Artifacts
+        uses: docker/bake-action@v5
+        with:
+          push: true
+          # Metadata Action のタグ出力を加工したいのでここではラベルのみを渡す
+          # タグの情報は環境変数 DOCKER_METADATA_OUTPUT_TAGS を使って受け取る
+          files: |
+            docker-bake.hcl
+            ${{ steps.meta.outputs.bake-file-labels }}
+          # 基本的に main ブランチのキャッシュしか共有できないのでキャッシュの保存はオプトインにしておく
+          set: |
+            *.cache-from=type=gha
+            ${{ inputs.save-cache && '*.cache-to=type=gha,mode=max' || '' }}

docker-bake.hcl

@@ -0,0 +1,24 @@
+group "default" {
+  targets = ["backend"]
+}
+
+target "docker-metadata-action" {}
+
+target "backend" {
+  inherits = ["docker-metadata-action"]
+  context = "./backend"
+  matrix = {
+    image = ["scoreserver"]
+  }
+  name = "backend-${image}"
+  tags = make_tags("${image}")
+  target = "${image}"
+}
+
+variable "DOCKER_METADATA_OUTPUT_TAGS" {
+    default = ""
+}
+function "make_tags" {
+    params = [ns]
+    result = split("\n", replace("${DOCKER_METADATA_OUTPUT_TAGS}", ":", "/${ns}:"))
+}