Add GitHub workflow for building and publishing docker image

.github/workflows/docker_publish.yml

@@ -0,0 +1,83 @@
+name: Create and publish a Docker image
+
+# Run this workflow every time a change is pushed to the branch called `release`
+on:
+  push:
+    branches: ['main']
+
+env:
+  # GitHub container registry
+  REGISTRY: ghcr.io
+
+  # Name used for Docker image
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  build-and-push-image:
+    runs-on: ubuntu-latest
+
+    # Set permissions granted to the `GITHUB_TOKEN` for the actions in this job
+    permissions:
+      contents: read
+      packages: write
+      attestations: write
+      id-token: write
+
+    steps:
+      # Checkout the repository
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Generate XNAT container service labels
+        id: xnat-command-label
+        run: |
+          import json
+          import os
+          repo_dir = os.getenv('GITHUB_WORKSPACE')
+          command_list = []
+          for file in os.listdir(repo_dir):
+              if file.endswith(".json"):
+                  with open(file) as f:
+                      command_object = json.load(f)
+                      command_string = json.dumps(command_object)
+                      command_list.append(command_string)
+          
+          commands = ','.join(command_list)
+          label = f'org.nrg.commands=[{commands}]'
+          with open(os.environ['GITHUB_OUTPUT'], 'a') as github_output:
+              print(f"label={label}", file=github_output)
+        shell: python
+
+      # Log into the container registry
+      - name: Log in to the Container registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      # Extract metadata (tags and labels) to be applied to the image. See [docker/metadata-action](https://github.com/docker/metadata-action#about)
+      # The `id` "meta" allows the output of this step to be referenced in a subsequent step. The `images` value provides the base name for the tags and labels.
+      - name: Extract metadata for Docker
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+#          labels: |
+#            # set xnat container service label defining commands in this image
+#            ${{ steps.xnat-command-label.outputs.label }}
+          tags: |
+            # set latest tag for default branch
+            type=raw,value=latest,enable={{is_default_branch}}
+
+      # Build the image from the Dockerfile in the repo and push to the container registry.
+      # The `context` parameter defines the build's context as the set of files located in the specified path. For more information, see "[Usage](https://github.com/docker/build-push-action#usage)" in the README of the `docker/build-push-action` repository.
+      # Tag and label the image using the output from the metadata step above
+      - name: Build and push Docker image
+        id: push
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}