Limit auxiliary Docker build contexts

docker/Dockerfile.controller.dockerignore

@@ -0,0 +1,20 @@
+# Controller image context allowlist.
+**
+
+!pyproject.toml
+!setup.py
+!requirements.txt
+!README.md
+!LICENSE
+
+!i[d]rac_ctl/
+!i[d]rac_ctl/**
+!redfish_ctl/
+!redfish_ctl/**
+!k8s/
+!k8s/controller/
+!k8s/controller/**
+
+**/__pycache__/
+**/*.py[cod]
+**/*.egg-info/

docker/Dockerfile.mock-bmc.dockerignore

@@ -0,0 +1,8 @@
+# Mock-BMC image context allowlist.
+**
+
+!k8s/
+!k8s/sandbox/
+!k8s/sandbox/mock_bmc_server.py
+!tests/
+!tests/supermicro_gb300_corpus.tar.gz

tests/gates/test_dockerfile_contract.py

@@ -4,6 +4,20 @@
 DOCKERFILE = REPO_ROOT / "docker" / "Dockerfile"
 DOCKER_README = REPO_ROOT / "docker" / "README.md"
 README = REPO_ROOT / "README.md"
+RELEASE_WORKFLOW = REPO_ROOT / ".github" / "workflows" / "release.yml"
+
+
+def _effective_ignore_rules(path: Path) -> list[str]:
+    """Return non-comment Docker ignore rules.
+
+    :param path: Docker ignore file to parse.
+    :return: Ordered non-empty rules with comments removed.
+    """
+    return [
+        line.strip()
+        for line in path.read_text(encoding="utf-8").splitlines()
+        if line.strip() and not line.lstrip().startswith("#")
+    ]
 
 
 def test_production_dockerfile_installs_local_otlp_wheel_as_non_root() -> None:
@@ -48,3 +62,48 @@ def test_docker_docs_link_the_production_image_usage() -> None:
     assert "exporter --output otlp" in docker_readme
     assert "credentials" in docker_readme.lower()
     assert "[Docker](docker/README.md)" in readme
+
+
+def test_published_auxiliary_images_use_minimal_context_allowlists() -> None:
+    """Published auxiliary images receive only the files copied by their Dockerfiles."""
+    expected_rules = {
+        "Dockerfile.controller": [
+            "**",
+            "!pyproject.toml",
+            "!setup.py",
+            "!requirements.txt",
+            "!README.md",
+            "!LICENSE",
+            "!i[d]rac_ctl/",
+            "!i[d]rac_ctl/**",
+            "!redfish_ctl/",
+            "!redfish_ctl/**",
+            "!k8s/",
+            "!k8s/controller/",
+            "!k8s/controller/**",
+            "**/__pycache__/",
+            "**/*.py[cod]",
+            "**/*.egg-info/",
+        ],
+        "Dockerfile.mock-bmc": [
+            "**",
+            "!k8s/",
+            "!k8s/sandbox/",
+            "!k8s/sandbox/mock_bmc_server.py",
+            "!tests/",
+            "!tests/supermicro_gb300_corpus.tar.gz",
+        ],
+    }
+
+    for dockerfile, rules in expected_rules.items():
+        ignore_file = REPO_ROOT / "docker" / f"{dockerfile}.dockerignore"
+        assert _effective_ignore_rules(ignore_file) == rules
+
+
+def test_release_auxiliary_images_use_the_guarded_contexts() -> None:
+    """Release builds keep the Dockerfile names bound to their matching allowlists."""
+    release_workflow = RELEASE_WORKFLOW.read_text(encoding="utf-8")
+
+    for dockerfile in ("Dockerfile.controller", "Dockerfile.mock-bmc"):
+        assert f"file: docker/{dockerfile}" in release_workflow
+        assert (REPO_ROOT / "docker" / f"{dockerfile}.dockerignore").is_file()