github/workflows: fix docker tags (#375)

Fixes "build" github action to:
 - Push "latest" tag on commits to main.
 - Push "git short sha" tag on commits to main.
 - Push "git tag" tag on tag pushes

category: bug
ticket: #339

.github/workflows/build.yml

@@ -2,7 +2,8 @@ on:
   push:
     branches:
       - main
-
+    tags:
+      - 'v*'
 name: Build docker image
 jobs:
   build-docker:
@@ -13,17 +14,19 @@ jobs:
 
     - uses: docker/setup-buildx-action@v1
 
-    - id: get-version
-      run: |
-        version=$(echo "${{ github.sha }}" | cut -c1-8)
-        echo "::set-output name=version::$version"
-
     - id: meta
       uses: docker/metadata-action@v3
       with:
-        images: |
-          ghcr.io/obolnetwork/charon/charon
-        tags: "latest,${{steps.get-version.outputs.version}}"
+        images: ghcr.io/obolnetwork/charon/charon
+        tags: |
+          # Tag "git short sha" on push to branch (main)
+          type=sha,event=branch
+
+          # Tag "latest" on all events
+          type=raw,value=latest
+
+          # Tag "tag ref" on tag push events
+          type=ref,event=tag
 
     - uses: docker/login-action@v1
       with:
@@ -38,5 +41,3 @@ jobs:
         push: true
         build-args: GITHUB_SHA=${{ github.sha }}
         tags: ${{ steps.meta.outputs.tags }}
-
-    - run: echo ${{ steps.docker_build.outputs.digest }}

.github/workflows/release.yml

@@ -10,34 +10,6 @@ jobs:
     steps:
     - uses: actions/checkout@v2
 
-    - uses: docker/setup-buildx-action@v1
-
-    - id: get-tag
-      run: |
-        tag=$(echo "${{ github.ref }}" | cut -d / -f 3)
-        echo "::set-output name=tag::$tag"
-
-    - id: meta
-      uses: docker/metadata-action@v3
-      with:
-        images: |
-          ghcr.io/obolnetwork/charon/charon
-        tags: "${{steps.get-tag.outputs.tag}}"
-
-    - uses: docker/login-action@v1
-      with:
-        registry: ghcr.io
-        username: ${{ github.actor }}
-        password: ${{ secrets.CONTAINER_REGISTRY_SECRET }}
-
-    - uses: docker/build-push-action@v2
-      with:
-        context: .
-        platforms: linux/amd64,linux/arm64
-        push: true
-        build-args: GITHUB_SHA=${{ github.sha }}
-        tags: ${{ steps.meta.outputs.tags }}
-
     - run: docker run ghcr.io/obolnetwork/charon/charon:${{steps.get-tag.outputs.tag}} charon run --help > cli-reference.txt
 
     - run: cat cli-reference.txt