Add a docker build

Author: JohnGarbutt

.github/workflows/docker.yaml

@@ -0,0 +1,56 @@
+name: Docker image
+# Run the tasks on every push
+on: push
+jobs:
+  build_push_api:
+    name: Build and push execution environment
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out the repository
+        uses: actions/checkout@v2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+
+      - name: Set up Docker layer caching
+        uses: actions/cache@v2
+        with:
+          path: /tmp/.buildx-cache
+          key: ${{ runner.os }}-buildx-${{ github.sha }}
+          restore-keys: |
+            ${{ runner.os }}-buildx-
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v1
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Calculate metadata for image
+        id: image-meta
+        uses: docker/metadata-action@v3
+        with:
+          images: ghcr.io/stackhpc/os-capacity
+          # Produce the branch name or tag and the SHA as tags
+          tags: |
+            type=ref,event=branch
+            type=ref,event=tag
+            type=sha,prefix=
+      - name: Build and push image
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.image-meta.outputs.tags }}
+          labels: ${{ steps.image-meta.outputs.labels }}
+          cache-from: type=local,src=/tmp/.buildx-cache
+          cache-to: type=local,dest=/tmp/.buildx-cache-new,mode=max
+
+      # Temp fix
+      # https://github.com/docker/build-push-action/issues/252
+      # https://github.com/moby/buildkit/issues/1896
+      # https://github.com/docker/buildx/pull/535
+      - name: Move cache
+        run: |
+          rm -rf /tmp/.buildx-cache
+          mv /tmp/.buildx-cache-new /tmp/.buildx-cache

Dockerfile

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+FROM ubuntu:22.04
+
+RUN apt-get update && apt-get upgrade -y && apt-get install python3-pip tini -y && apt-get clean
+
+COPY . /opt/os-capacity
+RUN pip install -U -e /opt/os-capacity
+
+ENTRYPOINT ["tini", "-g", "--"]
+CMD ["python3", "/opt/os-capacity/os_capacity/prometheus.yaml"]