Implement dynamic Docker build strategy

A new strategy has been implemented for the Docker build using a matrix from a JSON file. This approach allows flexibility in defining the Docker image builds and pushes, as it moves their configuration into the separate JSON file. The configuration is read, set as an output for a new "config" job, and then used in the original build-and-push job.

.github/workflows/docker-build.yml

@@ -12,6 +12,10 @@ jobs:
   build-and-push:
     runs-on: ubuntu-latest
 
+    strategy:
+      matrix:
+        include: ${{ fromJson(needs.config.outputs.matrix) }}
+
     steps:
       - name: Checkout code
         uses: actions/checkout@v2
@@ -25,39 +29,23 @@ jobs:
           username: ${{ secrets.DOCKER_HUB_USERNAME }}
           password: ${{ secrets.DOCKER_HUB_ACCESS_TOKEN }}
 
-      - name: Build and push Docker image for CentOS 7
-        uses: docker/build-push-action@v4
-        with:
-          context: .
-          platforms: linux/amd64,linux/arm64
-          push: true
-          tags: |
-            getpagespeed/rhel:centos7-lts
-            getpagespeed/rhel:el7-lts
-            getpagespeed/rhel:latest # Adjust this if you want the latest to point to a specific version
-          file: ./Dockerfile.el7
-
-      - name: Build and push Docker image for CentOS 8
-        uses: docker/build-push-action@v4
-        with:
-          context: .
-          platforms: linux/amd64,linux/arm64
-          push: true
-          tags: |
-            getpagespeed/rhel:centos8-lts
-            getpagespeed/rhel:el8-lts
-          file: ./Dockerfile.centos8
-
-      - name: Build and push Docker image for CentOS 9
+      - name: Build and push Docker image
         uses: docker/build-push-action@v4
         with:
           context: .
           platforms: linux/amd64,linux/arm64
           push: true
-          tags: |
-            getpagespeed/rhel:centos9-lts
-            getpagespeed/rhel:el9-lts
-          file: ./Dockerfile.centos9
+          tags: ${{ matrix.tags }}
+          file: ${{ matrix.file }}
 
       - name: Logout from Docker Hub
         run: docker logout
+
+  config:
+    runs-on: ubuntu-latest
+    outputs:
+      matrix: ${{ steps.config.outputs.matrix }}
+    steps:
+      - name: Read configuration
+        id: config
+        run: echo "::set-output name=matrix::$(cat docker-matrix.json)"

docker-matrix.json

@@ -0,0 +1,17 @@
+[
+  {
+    "name": "centos7-lts",
+    "file": "Dockerfile.centos7",
+    "tags": "getpagespeed/rhel:centos7-lts,getpagespeed/rhel:el7-lts"
+  },
+  {
+    "name": "centos8-lts",
+    "file": "Dockerfile.centos8",
+    "tags": "getpagespeed/rhel:centos8-lts,getpagespeed/rhel:el8-lts"
+  },
+  {
+    "name": "centos9-lts",
+    "file": "Dockerfile.centos9",
+    "tags": "getpagespeed/rhel:centos9-lts,getpagespeed/rhel:el9-lts"
+  }
+]