Split push image manifest

Author: dsotirakis

.github/workflows/push-to-gar-docker-multiarch.yaml

@@ -117,10 +117,16 @@ jobs:
         with:
           repository: ${{ env.action_repo }}
           ref: ${{ env.action_ref }}
+      - name: Checkout
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+        with:
+          repository: grafana/shared-workflows
+          ref: multiarch-docker-builds-using-sh-runners
           path: shared-workflows
-      - name: Download digests
-        uses: actions/download-artifact@v4
+      - name: Create and push image manifests
+        uses: ./shared-workflows/actions/create-and-push-image-manifests
         with:
+<<<<<<< Updated upstream
           path: /tmp/digests
           pattern: digests-*-${{ matrix.tags }}
           merge-multiple: true
@@ -147,3 +153,7 @@ jobs:
       - name: Inspect image
         run: |
           "docker buildx imagetools inspect ${{ needs.build-multi-arch.outputs.full_image_name }}:${{ steps.meta.outputs.version }}"
+=======
+          full-image-name: ${{ needs.build-multi-arch.outputs.full_image_name }}
+          tag: ${{ matrix.tags }}
+>>>>>>> Stashed changes

actions/create-and-push-image-manifests/action.yaml

@@ -0,0 +1,42 @@
+---
+description: Pulls image digests from GitHub and pushes manifests to GAR
+inputs:
+  full-image-name:
+    description: Image name to push the manifest for
+    required: true
+  tag:
+    description: Tag to create and push the manifest for
+    required: true
+name: Create and push image manifest
+
+runs:
+  using: composite
+  steps:
+    - name: Checkout
+      uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
+    - name: Download digests
+      uses: actions/download-artifact@v4
+      with:
+        merge-multiple: true
+        path: /tmp/digests
+        pattern: digests-*-${{ inputs.tag }}
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v3
+    - id: meta
+      name: Docker meta
+      uses: docker/metadata-action@v5
+      with:
+        images: ${{ inputs.full-image-name }}
+        tags: ${{ inputs.tag }}
+    - id: login-to-gar
+      uses: grafana/shared-workflows/actions/login-to-gar@main
+    - name: Create manifest list and push
+      working-directory: /tmp/digests
+      shell: bash
+      run: |
+        "docker buildx imagetools create $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \ $(printf '${{ inputs.full-image-name }}@sha256:%s ' *)"
+    - name: Inspect image
+      shell: bash
+      run: |
+        "docker buildx imagetools inspect ${{ inputs.full-image-name }}:${{ steps.meta.outputs.version }}"
+