fix: lazy-init K8s client for spark_application engine

Defer kubeconfig load until materialize/cleanup so feast apply can construct the engine without a cluster. Signed-off-by: Aniket Paluskar <apaluska@redhat.com>
ntkathole · Jul 17, 2026 · Jun 24, 2026 · Jul 3, 2026 · Jul 3, 2026 · Jul 3, 2026
commit cef6fa63289d0396b7598add2b74c5d0f3332a7c
@@ -91,12 +91,33 @@ def __init__(
                 "snowflake.registry, etc."
             )
 
-        k8s_config.load_config()
-        self.k8s_client = client.ApiClient()
-        self.core_v1 = client.CoreV1Api(self.k8s_client)
-        self.custom_api = client.CustomObjectsApi(self.k8s_client)
+        # Defer kubeconfig load until materialize/cleanup — feast apply only
+        # constructs the engine and calls update() (a no-op), so it must not
+        # require a cluster.
+        self._k8s_client = None
+        self._core_v1 = None
+        self._custom_api = None
         self._server_id = uuid.uuid4().hex[:8]
 
+    def _ensure_k8s(self) -> None:
+        """Load kubeconfig and create API clients on first K8s use."""
+        if self._custom_api is not None:
+            return
+        k8s_config.load_config()
+        self._k8s_client = client.ApiClient()
+        self._core_v1 = client.CoreV1Api(self._k8s_client)
+        self._custom_api = client.CustomObjectsApi(self._k8s_client)
+
+    @property
+    def core_v1(self):
+        self._ensure_k8s()
+        return self._core_v1
+
+    @property
+    def custom_api(self):
+        self._ensure_k8s()
+        return self._custom_api
+
     @property
     def supports_batch(self) -> bool:
         return True

@@ -55,15 +55,22 @@ def _make_repo_config(
 @patch("feast.infra.compute_engines.spark_application.compute.k8s_config")
 @patch("feast.infra.compute_engines.spark_application.compute.client")
 def _make_engine(mock_client, mock_k8s_config, **kwargs):
-    """Create engine with mocked K8s client."""
+    """Create engine with mocked K8s client.
+
+    Pre-seed API clients so later property access does not call real
+    load_config() after this helper's patches have exited.
+    """
     from feast.infra.compute_engines.spark_application.compute import (
         SparkApplicationComputeEngine,
     )
 
     repo_config = _make_repo_config(**kwargs)
-    return SparkApplicationComputeEngine(
+    engine = SparkApplicationComputeEngine(
         repo_config=repo_config, offline_store=None, online_store=None
     )
+    engine._core_v1 = MagicMock()
+    engine._custom_api = MagicMock()
+    return engine
 
 
 # ── Test 1: Config defaults + required field ──
@@ -124,6 +131,27 @@ def test_accepts_snowflake_registry():
     assert engine is not None
 
 
+@patch("feast.infra.compute_engines.spark_application.compute.k8s_config")
+@patch("feast.infra.compute_engines.spark_application.compute.client")
+def test_init_does_not_load_kubeconfig(mock_client, mock_k8s_config):
+    """feast apply constructs the engine but never materializes — no kubeconfig needed."""
+    from feast.infra.compute_engines.spark_application.compute import (
+        SparkApplicationComputeEngine,
+    )
+
+    engine = SparkApplicationComputeEngine(
+        repo_config=_make_repo_config(), offline_store=None, online_store=None
+    )
+    mock_k8s_config.load_config.assert_not_called()
+
+    _ = engine.core_v1
+    mock_k8s_config.load_config.assert_called_once()
+    assert engine.custom_api is not None
+    # Second access must not reload
+    _ = engine.custom_api
+    mock_k8s_config.load_config.assert_called_once()
+
+
 # ── Test 5: _build_driver_repo_config — one rewrite (batch_engine only) ──