CI: publish a Gitea release naming the IPCR image and digest on v* tags

.gitea/workflows/docker-publish.yml

@@ -36,7 +36,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     permissions:
-      contents: read
+      contents: write    # the release step below
       packages: write
 
     steps:
@@ -82,9 +82,48 @@ jobs:
             type=raw,value=${{ inputs.tag }},enable=${{ inputs.tag != '' }}
 
       - name: Build and push Docker image
+        id: build
         uses: docker/build-push-action@v5
         with:
           context: .
           push: true
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
+
+      # Gitea's Packages tab only lists images in Gitea's own registry, so a v* tag gets a
+      # release instead, naming the image it shipped. The digest line is the one to trust:
+      # ipcr 1.7.1 can drop some of the tags pushed together (see the tag list).
+      - name: Publish the Gitea release
+        if: startsWith(github.ref, 'refs/tags/v')
+        env:
+          TOKEN: ${{ secrets.GITEA_TOKEN }}
+          API: ${{ github.server_url }}/api/v1/repos/${{ github.repository }}
+          TAG: ${{ github.ref_name }}
+          SHA: ${{ github.sha }}
+          DIGEST: ${{ steps.build.outputs.digest }}
+          TAGS: ${{ steps.meta.outputs.tags }}
+          PULL: ipcr-watch.nsl.sh/ipns/metadec.eth/${{ env.IMAGE_NAME }}
+        run: |
+          node -e '
+            const e = process.env, ver = e.TAG.replace(/^v/, "");
+            const tags = e.TAGS.split("\n").filter(Boolean).map(t => "`" + t.split(":").pop() + "`");
+            const body = [
+              "**Image** (anonymous pull):",
+              "```", `docker pull ${e.PULL}:${ver}`, "```",
+              "Pinned by digest:",
+              "```", `${e.PULL}@${e.DIGEST}`, "```",
+              `Tags pushed: ${tags.join(", ")} · commit ${e.SHA.slice(0, 7)}`,
+            ].join("\n");
+            console.log(JSON.stringify({ tag_name: e.TAG, name: e.TAG, body }));
+          ' > /tmp/release.json
+          auth="Authorization: token $TOKEN"
+          code=$(curl -s -o /tmp/existing.json -w '%{http_code}' -H "$auth" "$API/releases/tags/$TAG")
+          if [ "$code" = 200 ]; then
+            id=$(node -p 'require("/tmp/existing.json").id')
+            method=PATCH url="$API/releases/$id"
+          else
+            method=POST url="$API/releases"
+          fi
+          code=$(curl -s -o /tmp/out.json -w '%{http_code}' -X "$method" -H "$auth" \
+            -H 'Content-Type: application/json' --data @/tmp/release.json "$url")
+          case "$code" in 2*) echo "release $TAG: $method $code" ;; *) cat /tmp/out.json; exit 1 ;; esac