Build main image on arm (space-ros#206)

Also moves around common environment varaibles to a global level.

Author: dsobek

.github/workflows/earthly-build.yaml

@@ -7,11 +7,26 @@ on:
   pull_request:
   schedule:
     - cron: "0 11 * * *"
+
+env:
+  BASE_IMAGE_TAG: "${{ github.head_ref || github.ref_name }}"
+  VCS_REF: ${{ github.sha }}
+  GHCR_IMAGE_NAME: "ghcr.io/space-ros/space-ros"
+  DOCKER_HUB_USERNAME: osrfbot
+  DOCKER_HUB_TOKEN: ${{ secrets.DOCKER_HUB_RW_TOKEN }}
+  DOCKER_HUB_IMAGE_NAME: "osrf/space-ros"
+
 jobs:
-  build-test:
-    env:
-      VCS_REF: ${{ github.sha }}
+  define-architecture-matrix:
+    runs-on: ubuntu-latest
+    outputs:
+      architecture-matrix: ${{ steps.define-matrix.arch-matrix}}
+    steps: 
+      - id: define-matrix
+        run: |
+          echo 'arch-matrix=[{"runner": "ubuntu-latest", "arch": "x86"}, {"runner": "ubuntu-20.04-arm", "arch": "arm64"},]' >> "$GITHUB_OUTPUT"
 
+  build-test:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
@@ -33,30 +48,41 @@ jobs:
           if-no-files-found: error
 
   space-ros-main-image:
-    runs-on: ubuntu-latest
+    needs: define-architecture-matrix
+    strategy:
+      matrix:
+        arch-info: ${{ fromJSON(needs.define-architecture-matrix.outputs.architecture-matrix) }}
+    # Keep in sync with the architecture-matrix arch values.
+    outputs:
+      output_x86: ${{ steps.push_image.outputs.output_x86 }}
+      output_arm64: ${{ steps.push_image.outputs.output_arm64 }}
+    runs-on: ${{ matrix.arch-info.runner }}
     env:
-      IMAGE_TAG: "${{ github.head_ref || github.ref_name }}"
-      VCS_REF: ${{ github.sha }}
-      GHCR_IMAGE_NAME: "ghcr.io/space-ros/space-ros"
-      DOCKER_HUB_USERNAME: osrfbot
-      DOCKER_HUB_TOKEN: ${{ secrets.DOCKER_HUB_RW_TOKEN }}
-      DOCKER_HUB_IMAGE_NAME: "osrf/space-ros"
+      ARCH_IMAGE_TAG: "${{ env.BASE_IMAGE_TAG }}-${{ matrix.arch-info.arch }}"
 
     steps:
       - name: Checkout
         uses: actions/checkout@v3
 
       - name: Set up earthly
         run: |
-          sudo wget https://github.com/earthly/earthly/releases/latest/download/earthly-linux-amd64 -O /usr/local/bin/earthly
+          sudo wget https://github.com/earthly/earthly/releases/latest/download/earthly-linux-${{ matrix.arch-info.arch }} -O /usr/local/bin/earthly
           sudo chmod 755 /usr/local/bin/earthly
 
-      - name: Build spaceros image without pushing
+      - name: Login to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ env.DOCKER_HUB_USERNAME }}
+          password: ${{ env.DOCKER_HUB_TOKEN }}
+
+      - name: Build spaceros image and push it to Dockerhub
+        id: push_image
         run: |
           earthly --ci --output +push-main-image \
             --VCS_REF="$VCS_REF" \
-            --IMAGE_TAG="$IMAGE_TAG" \
+            --IMAGE_TAG="$ARCH_IMAGE_TAG" \
             --IMAGE_NAME="$DOCKER_HUB_IMAGE_NAME"
+          echo "output_${{ matrix.arch-info.arch }}=$DOCKER_HUB_IMAGE_NAME:$ARCH_IMAGE_TAG" >> "$GITHUB_OUTPUT"
 
       # Login and push the main builds to GHCR
       - name: Login to GHCR
@@ -70,35 +96,41 @@ jobs:
       - name: Push the main spaceros image to GHCR
         if: ${{ github.ref_name == 'main' }}
         run: |
-          docker tag "$DOCKER_HUB_IMAGE_NAME:$IMAGE_TAG" "$GHCR_IMAGE_NAME:$IMAGE_TAG"
-          docker push "$GHCR_IMAGE_NAME:$IMAGE_TAG"
+          docker tag "$DOCKER_HUB_IMAGE_NAME:$ARCH_IMAGE_TAG" "$GHCR_IMAGE_NAME:$ARCH_IMAGE_TAG"
+          docker push "$GHCR_IMAGE_NAME:$ARCH_IMAGE_TAG"
 
-      # Push both tagged releases and the latest main builds to Dockerhub
-      - name: Push spaceros images to Dockerhub
-        if: ${{ github.ref_type == 'tag' || github.ref_name == 'main' }}
-        run: |
-          # We must login using the password and not the action, as the action only supports tokens.
-          echo "$DOCKER_HUB_TOKEN" | docker login --username "$DOCKER_HUB_USERNAME" --password-stdin
-          docker push "$DOCKER_HUB_IMAGE_NAME:$IMAGE_TAG"
 
+  combine-main-image-manifests:
+    env:
+      IMAGE_TAG: "${{ env.BASE_IMAGE_TAG }}"
+      
+    runs-on: ubuntu-latest
+    needs: space-ros-main-image
+    steps:
+      - name: Login to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ env.DOCKER_HUB_USERNAME }}
+          password: ${{ env.DOCKER_HUB_TOKEN }}
+
+      - name: Combine Manifests
+        run: |
+          docker manifest create osrf/space-ros:${{ github.ref_name }} \
+            --amend ${{ join(needs.space-ros-main-image.outputs, ' --amend ') }}
+          docker manifest push $DOCKER_HUB_IMAGE_NAME:$IMAGE_TAG
+          
       # Any tagged image should also be marked as "latest"
       - name: Push spaceros latest images to Dockerhub
         if: ${{ github.ref_type == 'tag' }}
         run: |
           # We must login using the password and not the action, as the action only supports tokens.
-          echo "$DOCKER_HUB_TOKEN" | docker login --username "$DOCKER_HUB_USERNAME" --password-stdin
           docker tag "$DOCKER_HUB_IMAGE_NAME:$IMAGE_TAG" "$DOCKER_HUB_IMAGE_NAME:latest"
           docker push "$DOCKER_HUB_IMAGE_NAME:latest"
 
   space-ros-dev-image:
     runs-on: ubuntu-latest
     env:
-      IMAGE_TAG: "${{ github.head_ref || github.ref_name }}-dev"
-      VCS_REF: ${{ github.sha }}
-      GHCR_IMAGE_NAME: "ghcr.io/space-ros/space-ros"
-      DOCKER_HUB_USERNAME: osrfbot
-      DOCKER_HUB_TOKEN: ${{ secrets.DOCKER_HUB_RW_TOKEN }}
-      DOCKER_HUB_IMAGE_NAME: "osrf/space-ros"
+      IMAGE_TAG: "${{ env.BASE_IMAGE_TAG }}-dev"
 
     steps:
       - name: Checkout
@@ -116,7 +148,6 @@ jobs:
             --IMAGE_TAG="$IMAGE_TAG" \
             --IMAGE_NAME="$DOCKER_HUB_IMAGE_NAME"
 
-      # Only push the main dev builds to GHCR
       - name: Login to GHCR
         uses: docker/login-action@v3
         if: ${{ github.ref_name == 'main' }}
@@ -125,6 +156,7 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
+      # Only push the main dev builds to GHCR
       - name: Push the dev spaceros image to GHCR
         if: ${{ github.ref_name == 'main' }}
         run: |