fix(docker): keep DOCKER_HOST on from_env so TLS settings apply; a missing current context is an error

strix/runtime/docker_connection.py

@@ -33,7 +33,7 @@ class DockerEndpoint:
 
     @property
     def label(self) -> str:
-        return f"{self.host or 'default socket'} ({self.source})"
+        return f"{self.host} ({self.source})" if self.host else self.source
 
 
 class DockerConnectionError(RuntimeError):
@@ -59,22 +59,26 @@ def resolve_docker_endpoint(environ: dict[str, str] | None = None) -> DockerEndp
         return DockerEndpoint(host, "DOCKER_HOST")
 
     name = get_current_context_name()
-    if name != DEFAULT_CONTEXT:
-        try:
-            context = ContextAPI.get_context(name)
-        except Exception:  # noqa: BLE001 - a broken context file must not hide Docker itself
-            context = None
-        if context is not None and context.Host:
-            return DockerEndpoint(context.Host, f"docker context '{name}'", context.TLSConfig)
-    return DockerEndpoint(None, "default socket")
+    if name == DEFAULT_CONTEXT:
+        return DockerEndpoint(None, "default socket")
+
+    source = f"docker context '{name}'"
+    try:
+        context = ContextAPI.get_context(name)
+    except DockerException as exc:
+        raise DockerConnectionError(DockerEndpoint(None, source), exc) from exc
+    if context is None:
+        missing = DockerException(f"{source} is selected but does not exist")
+        raise DockerConnectionError(DockerEndpoint(None, source), missing)
+    return DockerEndpoint(context.Host, source, context.TLSConfig)
 
 
 def connect_docker() -> Any:
     """Return a ``docker.DockerClient`` for the resolved endpoint or raise DockerConnectionError."""
     endpoint = resolve_docker_endpoint()
     try:
-        if endpoint.host is None:
-            return docker.from_env()
+        if endpoint.source == "DOCKER_HOST" or endpoint.host is None:
+            return docker.from_env()  # also reads DOCKER_TLS_VERIFY and DOCKER_CERT_PATH
         return docker.DockerClient(base_url=endpoint.host, tls=endpoint.tls or False)
     except DockerException as exc:
         raise DockerConnectionError(endpoint, exc) from exc

tests/test_docker_connection.py

@@ -51,17 +51,64 @@ def test_current_context_is_used_like_the_cli(monkeypatch: pytest.MonkeyPatch) -
     assert endpoint.source == "docker context 'desktop-linux'"
 
 
-def test_default_and_broken_contexts_fall_back_to_the_sdk(monkeypatch: pytest.MonkeyPatch) -> None:
+def test_default_context_uses_the_sdk_default(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setattr(docker_connection, "get_current_context_name", lambda: "default")
     assert resolve_docker_endpoint({}) == DockerEndpoint(None, "default socket")
 
-    monkeypatch.setattr(docker_connection, "get_current_context_name", lambda: "gone")
 
-    def boom(_name: str) -> SimpleNamespace:
-        raise ValueError("bad meta.json")
+def test_missing_or_broken_current_context_is_an_error(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr(docker_connection, "get_current_context_name", lambda: "gone")
+    monkeypatch.setattr(
+        "strix.runtime.docker_connection.ContextAPI.get_context", lambda _name: None
+    )
+    with pytest.raises(
+        DockerConnectionError, match="docker context 'gone' is selected but does not exist"
+    ):
+        resolve_docker_endpoint({})
+
+    def boom(_name: str) -> None:
+        raise DockerException("bad meta.json")
 
     monkeypatch.setattr("strix.runtime.docker_connection.ContextAPI.get_context", boom)
-    assert resolve_docker_endpoint({}) == DockerEndpoint(None, "default socket")
+    with pytest.raises(DockerConnectionError, match="bad meta") as info:
+        resolve_docker_endpoint({})
+    assert info.value.endpoint.label == "docker context 'gone'"
+
+
+def test_docker_host_goes_through_from_env_so_tls_settings_apply(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setattr(
+        docker_connection,
+        "resolve_docker_endpoint",
+        lambda _environ=None: DockerEndpoint("tcp://10.0.0.5:2376", "DOCKER_HOST"),
+    )
+    client = object()
+    monkeypatch.setattr("strix.runtime.docker_connection.docker.from_env", lambda: client)
+
+    def unexpected(**_kwargs: Any) -> None:
+        raise AssertionError("DOCKER_HOST must not bypass from_env")
+
+    monkeypatch.setattr("strix.runtime.docker_connection.docker.DockerClient", unexpected)
+    assert docker_connection.connect_docker() is client
+
+
+def test_context_endpoint_keeps_its_tls_config(monkeypatch: pytest.MonkeyPatch) -> None:
+    tls = object()
+    monkeypatch.setattr(
+        docker_connection,
+        "resolve_docker_endpoint",
+        lambda _environ=None: DockerEndpoint("tcp://remote:2376", "docker context 'remote'", tls),
+    )
+    seen: dict[str, Any] = {}
+
+    def client(**kwargs: Any) -> str:
+        seen.update(kwargs)
+        return "client"
+
+    monkeypatch.setattr("strix.runtime.docker_connection.docker.DockerClient", client)
+    assert docker_connection.connect_docker() == "client"
+    assert seen == {"base_url": "tcp://remote:2376", "tls": tls}
 
 
 @pytest.mark.parametrize(
@@ -78,7 +125,7 @@ def test_connect_docker_surfaces_the_root_cause(
     monkeypatch.setattr(
         docker_connection,
         "resolve_docker_endpoint",
-        lambda _environ=None: DockerEndpoint("unix:///nope.sock", "DOCKER_HOST"),
+        lambda _environ=None: DockerEndpoint("unix:///nope.sock", "docker context 'dead'"),
     )
 
     def dead_client(**_kwargs: Any) -> None:
@@ -117,7 +164,7 @@ def test_check_docker_connection_prints_endpoint_and_error_then_exits(
     assert exit_info.value.code == 1
     assert reported == [("docker_unavailable", PermissionError)]
     assert "DOCKER NOT AVAILABLE" in out
-    assert "default socket (default socket)" in out
+    assert "Cannot connect to Docker at default socket." in out
     assert "PermissionError: [Errno 13] Permission denied" in out
     assert "docker info" in out