ci: retry build on cache miss

Out build pipeline fails on "stale" branches and runs into cache not found errors. To circumvent this, we first try to build the image with cache and should that fail, we try again without cache.

Author: phbelitz

.github/workflows/101_build.yml

@@ -10,7 +10,7 @@ on:
         type: string
         default: "all"
     outputs:
-      chart_version: 
+      chart_version:
         description: "Connaisseur Helm chart version"
         value: ${{ jobs.context.outputs.chart_version }}
       original_registry:
@@ -35,7 +35,8 @@ on:
         description: "Workflow build tag used for testing (unique for each run)"
         value: ${{ jobs.context.outputs.build_tag }}
       build_image:
-        description: "Workflow build image used for testing, i.e. registry + repository + tag"
+        description: "Workflow build image used for testing, i.e. registry + repository
+          + tag"
         value: ${{ jobs.context.outputs.build_image }}
       build_labels:
         description: "Repository- and workflow-specific build labels"
@@ -119,8 +120,8 @@ jobs:
           BUILD_TAG="${BUILD_IMAGE//${PREFIX}/}"
           [[ ${BUILD_TAG} == "sha-"* ]] || exit 1 # check as parsing of the BUILD_TAG maybe fragile and dependent on docker/metadata-action priorities
           REF_TAGS="${REF_TAGS//${BUILD_TAG}/}"
-          
-  
+
+
           echo CHART_VERSION=${CHART_VERSION} >> ${GITHUB_OUTPUT}
           echo ORIGINAL_REGISTRY=${ORIGINAL_REGISTRY} >> ${GITHUB_OUTPUT}
           echo ORIGINAL_REPO=${ORIGINAL_REPO} >> ${GITHUB_OUTPUT}
@@ -136,7 +137,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     if: inputs.jobs_to_run != 'skip-all'
-    needs: [context]
+    needs: [ context ]
     permissions:
       packages: write
     steps:
@@ -158,8 +159,9 @@ jobs:
           TAGS="${PREFIX}${{ needs.context.outputs.build_tag }},$(echo ${{ needs.context.outputs.ref_tags }} | tr ' ' '\n' | awk '{print "${PREFIX}"$1}' | envsubst | tr '\n' ',')"
           echo tags=${TAGS} >> ${GITHUB_OUTPUT}
         shell: bash
-      - name: Build and push image
-        id: build
+      - name: Build and push image (with cache)
+        id: build_cached
+        continue-on-error: true
         uses: docker/build-push-action@bcafcacb16a39f128d818304e6c9c0c18556b85f # v7.1.0
         with:
           push: true
@@ -169,7 +171,19 @@ jobs:
           labels: ${{ needs.context.outputs.build_labels }}
           tags: ${{ steps.tags.outputs.tags }}
           sbom: false
-          provenance: false  #TODO: Set to false, as resulting format is not OCI (GHCR) compliant (https://github.com/docker/build-push-action/issues/820) and causes problems with GHCR and e.g. image deletion (https://github.com/snok/container-retention-policy/issues/63)
+          provenance: false #TODO: Set to false, as resulting format is not OCI (GHCR) compliant (https://github.com/docker/build-push-action/issues/820) and causes problems with GHCR and e.g. image deletion (https://github.com/snok/container-retention-policy/issues/63)
+      - name: Build and push image (without cache)
+        id: build
+        if: steps.build_cached.outcome == 'failure'
+        uses: docker/build-push-action@bcafcacb16a39f128d818304e6c9c0c18556b85f # v7.1.0
+        with:
+          push: true
+          cache-to: type=gha,scope=build-${{ github.ref_name }},mode=max
+          file: build/Dockerfile
+          labels: ${{ needs.context.outputs.build_labels }}
+          tags: ${{ steps.tags.outputs.tags }}
+          sbom: false
+          provenance: false #TODO: Set to false, as resulting format is not OCI (GHCR) compliant (https://github.com/docker/build-push-action/issues/820) and causes problems with GHCR and e.g. image deletion (https://github.com/snok/container-retention-policy/issues/63)
       - name: Show build information
         run: |
           echo "# :building_construction: Build Information" >> ${GITHUB_STEP_SUMMARY}
@@ -178,7 +192,7 @@ jobs:
           echo "<tr><td>Original image</td><td><code>${{ needs.context.outputs.original_image }}</code></td></tr>" >> ${GITHUB_STEP_SUMMARY}
           echo "<tr><td>Workflow image</td><td><code>${{ needs.context.outputs.build_registry }}/${{ needs.context.outputs.build_repo }}:${{ needs.context.outputs.build_tag }}</code></td></tr>" >> ${GITHUB_STEP_SUMMARY}
           echo "<tr><td>All images</td><td><code>$(echo ${{ steps.tags.outputs.tags }} | tr ',' '\n')</code></td></tr>" >> ${GITHUB_STEP_SUMMARY}
-          echo "<tr><td>Digest</td><td><code>${{ steps.build.outputs.digest }}</code></td></tr>" >> ${GITHUB_STEP_SUMMARY}
+          echo "<tr><td>Digest</td><td><code>${{ steps.build_cached.outputs.digest || steps.build.outputs.digest }}</code></td></tr>" >> ${GITHUB_STEP_SUMMARY}
           echo "</table>" >> ${GITHUB_STEP_SUMMARY}
           echo "" >> ${GITHUB_STEP_SUMMARY}
         shell: bash