half broken

.github/workflows/ci.yml

@@ -184,11 +184,29 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Build 
+      # `github.sha` exists on GitHub and on Gitea (which aliases the github
+      # context). The `gitea.*` context only exists on Gitea, so a workflow
+      # under .github/ that used it could never tag an image here.
+      #
+      # The image is published by .gitea/workflows/build.yaml on the real
+      # runner, which is the one with registry access; this job only pushes
+      # when this repository has been given a token for it, so a GitHub runner
+      # without credentials builds and stops instead of failing the pipeline.
+      - name: Build
         run: |
-          docker build -t $IMAGE:${{ gitea.sha }} -t $IMAGE:latest .
+          docker build --build-arg VERSION=${{ github.sha }} \
+            -t $IMAGE:${{ github.sha }} -t $IMAGE:latest .
+
+      - name: Log in to the registry
+        if: ${{ secrets.FANCYDNS_REGISTRY_TOKEN != '' }}
+        uses: docker/login-action@v3
+        with:
+          registry: registry.k6n.net
+          username: ${{ secrets.FANCYDNS_REGISTRY_USER }}
+          password: ${{ secrets.FANCYDNS_REGISTRY_TOKEN }}
 
       - name: Push image
+        if: ${{ secrets.FANCYDNS_REGISTRY_TOKEN != '' }}
         run: |
-          docker push $IMAGE:${{ gitea.sha }}
+          docker push $IMAGE:${{ github.sha }}
           docker push $IMAGE:latest