fix: prevent duplicate volumes when same PVC is mounted to multiple paths

When the same PVC is configured with multiple mount paths in the web UI,
add_notebook_volume appends a V1Volume with the same name for each mount,
causing a Kubernetes validation error due to duplicate volume names in the
PodSpec. Add a name-based deduplication check to skip volumes that already
exist.

Signed-off-by: Jaehyeon1020 <jaehyeon.kim1020@navercorp.com>

Author: Jaehyeon1020

components/crud-web-apps/jupyter/backend/apps/common/volumes.py

@@ -136,6 +136,12 @@ def add_notebook_volume(notebook, volume):
     if "volumes" not in podspec:
         podspec["volumes"] = []
 
+    # Skip if a volume with the same name already exists to avoid
+    # duplicate entries when the same PVC is mounted to multiple paths
+    for existing in podspec["volumes"]:
+        if existing["name"] == volume["name"]:
+            return notebook
+
     podspec["volumes"].append(volume)
     return notebook
 

components/crud-web-apps/jupyter/backend/apps/common/volumes_test.py

@@ -111,3 +111,37 @@ def test_use_pvc_name_in_volume_source(self):
                 "claimName": PVC_NAME,
             },
         })
+
+
+class TestAddNotebookVolume(unittest.TestCase):
+    """Test the functionality of the add_notebook_volume function."""
+
+    def setUp(self):
+        """Create a minimal Notebook CR dict."""
+        self.notebook = {
+            "spec": {
+                "template": {
+                    "spec": {
+                        "containers": [{"volumeMounts": []}],
+                    },
+                },
+            },
+        }
+        self.volume = {
+            "name": PVC_NAME,
+            "persistentVolumeClaim": {"claimName": PVC_NAME},
+        }
+
+    def test_add_volume(self):
+        """Add a volume to the Notebook's PodSpec."""
+        volumes.add_notebook_volume(self.notebook, self.volume)
+        podspec = self.notebook["spec"]["template"]["spec"]
+        self.assertEqual(len(podspec["volumes"]), 1)
+        self.assertEqual(podspec["volumes"][0]["name"], PVC_NAME)
+
+    def test_skip_duplicate_volume(self):
+        """Skip adding a volume if one with the same name already exists."""
+        volumes.add_notebook_volume(self.notebook, self.volume)
+        volumes.add_notebook_volume(self.notebook, self.volume)
+        podspec = self.notebook["spec"]["template"]["spec"]
+        self.assertEqual(len(podspec["volumes"]), 1)