Merge pull request #108 from garethjevans/cosign

Sign with cosign

Author: garethjevans

.github/workflows/release.yaml

@@ -6,9 +6,16 @@ on:
     tags:
       - '*'
 
+
 jobs:
   goreleaser:
     runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+      # This is used to complete the identity challenge
+      # with sigstore/fulcio when running outside of PRs.
+      id-token: write
     steps:
       - name: Checkout
         uses: actions/checkout@v2
@@ -45,9 +52,18 @@ jobs:
             TAGS="$TAGS,${DOCKER_IMAGE}:sha-${GITHUB_SHA::8}"
           fi
           echo ::set-output name=version::${VERSION}
+          echo ::set-output name=image::${DOCKER_IMAGE}
           echo ::set-output name=tags::${TAGS}
           echo ::set-output name=created::$(date -u +'%Y-%m-%dT%H:%M:%SZ')
 
+      # Install the cosign tool except on PR
+      # https://github.com/sigstore/cosign-installer
+      - name: Install cosign
+        if: github.event_name != 'pull_request'
+        uses: sigstore/cosign-installer@1e95c1de343b5b0c23352d6417ee3e48d5bcd422
+        with:
+          cosign-release: 'v1.4.0'
+
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v1
 
@@ -61,7 +77,7 @@ jobs:
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
       - name: Build and push
-        id: docker_build
+        id: build-and-push
         uses: docker/build-push-action@v2
         with:
           context: .
@@ -77,3 +93,16 @@ jobs:
             org.label-schema.url=${{ github.event.repository.html_url }}
             org.label-schema.vcs-ref=${{ github.sha }}
             org.label-schema.build-date=${{ steps.prep.outputs.created }}
+
+      # Sign the resulting Docker image digest except on PRs.
+      # This will only write to the public Rekor transparency log when the Docker
+      # repository is public to avoid leaking data.  If you would like to publish
+      # transparency data even for private images, pass --force to cosign below.
+      # https://github.com/sigstore/cosign
+      - name: Sign the published Docker image
+        if: ${{ github.event_name != 'pull_request' }}
+        env:
+          COSIGN_EXPERIMENTAL: "true"
+        # This step uses the identity token to provision an ephemeral certificate
+        # against the sigstore community Fulcio instance.
+        run: cosign sign ${{ steps.prep.outputs.image }}@${{ steps.build-and-push.outputs.digest }}