In CI always build images locally; outside CI pull then build as fallback

- pull_or_build_image: when GITHUB_ACTIONS=true, always build from the
  local build context (uploaded source) instead of checking for a
  pre-loaded or registry image. Outside CI, try pull first, build on failure.
- remote.py: forward GITHUB_ACTIONS=true over SSH so nodes see it.
- tests.yml: remove the build-and-load step; nodes now build images
  themselves during deployment, so pre-loading is unnecessary.

Author: szachovy

.github/workflows/tests.yml

@@ -53,29 +53,6 @@ jobs:
         run: "terraform apply --auto-approve"
         working-directory: "${{ env.TERRAFORM_WORKING_DIRECTORY }}"
 
-      - name: "Build and pre-load service images into test containers"
-        run: |
-          set -o pipefail
-          build_and_load() {
-            local image_name="$1"
-            local build_context="$2"
-            shift 2
-            local nodes=("$@")
-            docker build --quiet -t "${image_name}:latest" "$build_context"
-            for node in "${nodes[@]}"; do
-              docker save "${image_name}:latest" | docker exec -i "$node" docker load
-            done
-            docker rmi "${image_name}:latest" || true
-            docker image prune --force
-          }
-          build_and_load "ghcr.io/szachovy/superset-cluster-mysql-server" \
-            "services/mysql-server" node-2 node-3 node-4
-          build_and_load "ghcr.io/szachovy/superset-cluster-mysql-mgmt" \
-            "services/mysql-mgmt" node-0 node-1
-          build_and_load "ghcr.io/szachovy/superset-cluster-superset-service" \
-            "services/superset" node-0 node-1
-          docker image prune --all --force
-
       - name: "Run Ansible testsuite"
         run: |
           set -o pipefail

src/container.py

@@ -102,9 +102,9 @@ def __init__(self, container: str | None) -> None:
 
     @staticmethod
     def pull_or_build_image(client: docker.client.DockerClient, image: str, build_context: str) -> None:
-        try:
-            client.images.get(image)
-        except docker.errors.ImageNotFound:
+        if os.environ.get("GITHUB_ACTIONS") == "true":
+            client.images.build(path=build_context, tag=image)
+        else:
             try:
                 client.images.pull(image)
             except (docker.errors.DockerException, requests.exceptions.RequestException):

src/remote.py

@@ -125,8 +125,9 @@ def run_python_container_command(self, command: str) -> dict:
         ) as memfile:
             source = memfile.read() + command
         self.upload_file(content=source, remote_file_path=f'/opt/{nonce}.py')
+        github_actions_env = "GITHUB_ACTIONS=true " if os.environ.get("GITHUB_ACTIONS") == "true" else ""
         _, stdout, stderr = self.ssh_client.exec_command(
-            f"PYTHONPATH=/home/superset/.local/lib/python3.10/site-packages python3 /opt/{nonce}.py"
+            f"{github_actions_env}PYTHONPATH=/home/superset/.local/lib/python3.10/site-packages python3 /opt/{nonce}.py"
         )
         result = {
             "output": stdout.read().decode(),