Use a build-job matrix so components can be built in parallel

.github/workflows/main.yml

@@ -16,27 +16,41 @@ permissions:
   contents: read
   packages: write
 
+# build components using a job matrix, so they can run in parallel
 jobs:
   build:
-    # The type of runner that the job will run on
     runs-on: ubuntu-20.04
+    env:
+      TAG: ${GITHUB_SHA::8}
+    strategy:
+      fail-fast: true  # cancel all in-progress jobs if any matrix job fails
+      matrix:
+        component:
+          - downloader
+          - restreamer
+          - backfiller
+          - thrimshim
+          - cutter
+          - sheetsync
+          - nginx
+          - postgres
+          - segment_coverage
+          - playlist_manager
     steps:
-      # Checks out repository under $GITHUB_WORKSPACE, so we can access it
-      - uses: actions/checkout@v2
-      
+      - name: Check out repo
+        uses: actions/checkout@v2
+
       - name: Log into ghcr.io
         uses: docker/login-action@v1
         with:
           registry: ghcr.io
           username: ${{ github.repository_owner }}
           password: ${{ secrets.GITHUB_TOKEN }}
-          
-      - name: Run build script
-        run: |
-            # always push
-            export PUSH=true
-            # if this is a push to master and not a PR, also push latest - GITHUB_HEAD_REF is only set for PRs
-            if [ -z ${GITHUB_HEAD_REF+x} ] && [ "$GITHUB_REF" == "refs/heads/master" ]; then export PUSH=latest; fi
-            # build and push all components. try to pull and re-use layers from images for all parent commits.
-            'CACHE_FROM=$(git rev-list HEAD -n1 --parents | cut -d" " -f 2-) ./build'
-  
+
+      - name: Build ${{ matrix.component }}
+        uses: docker/build-push-action@v2.7.0
+        with:
+          context: ./${{ matrix.component }}
+          file: Dockerfile
+          tags: ghcr.io/ekimekim/wubloader-${{ matrix.component }}:$TAG,ghcr.io/ekimekim/wubloader-${{ matrix.component }}:latest
+          push: true