fix(sessions): Accept Vertex session resource names

Normalize fully qualified Vertex session resource names before building Agent Engine session paths. This keeps strict plain session ID validation while allowing Gemini Enterprise and Vertex resource-name callers to query sessions successfully.

Author: Raghu

src/google/adk/sessions/vertex_ai_session_service.py

@@ -48,6 +48,11 @@
 _USAGE_METADATA_CUSTOM_METADATA_KEY = '_usage_metadata'
 
 _SESSION_ID_PATTERN = re.compile(r'^[A-Za-z0-9_-]+$')
+_SESSION_RESOURCE_NAME_PATTERN = re.compile(
+    r'^projects/[^/]+/locations/[^/]+/'
+    r'(?:collections/[^/]+/engines/[^/]+|reasoningEngines/[^/]+)/'
+    r'sessions/([^/]+)$'
+)
 
 
 def _validate_session_id(session_id: str) -> None:
@@ -61,6 +66,19 @@ def _validate_session_id(session_id: str) -> None:
     )
 
 
+def _normalize_session_id(session_id: str) -> str:
+  """Returns the plain session ID from a session ID or Vertex resource name."""
+  match = (
+      _SESSION_RESOURCE_NAME_PATTERN.fullmatch(session_id)
+      if isinstance(session_id, str)
+      else None
+  )
+  if match:
+    session_id = match.group(1)
+  _validate_session_id(session_id)
+  return session_id
+
+
 def _quote_filter_literal(value: str) -> str:
   """Quotes filter values so embedded metacharacters stay inside the literal."""
   escaped_value = value.replace('\\', '\\\\').replace('"', '\\"')
@@ -178,7 +196,7 @@ async def get_session(
       session_id: str,
       config: Optional[GetSessionConfig] = None,
   ) -> Optional[Session]:
-    _validate_session_id(session_id)
+    session_id = _normalize_session_id(session_id)
     reasoning_engine_id = self._get_reasoning_engine_id(app_name)
     session_resource_name = (
         f'reasoningEngines/{reasoning_engine_id}/sessions/{session_id}'
@@ -278,7 +296,7 @@ async def list_sessions(
   async def delete_session(
       self, *, app_name: str, user_id: str, session_id: str
   ) -> None:
-    _validate_session_id(session_id)
+    session_id = _normalize_session_id(session_id)
     reasoning_engine_id = self._get_reasoning_engine_id(app_name)
     session_resource_name = (
         f'reasoningEngines/{reasoning_engine_id}/sessions/{session_id}'

tests/unittests/sessions/test_vertex_ai_session_service.py

@@ -725,6 +725,53 @@ async def test_get_and_delete_session():
   assert str(excinfo.value) == '404 Session not found: 1'
 
 
+@pytest.mark.asyncio
+@pytest.mark.usefixtures('mock_get_api_client')
+@pytest.mark.parametrize(
+    'resource_name',
+    [
+        (
+            'projects/my-project/locations/global/collections/'
+            'default_collection/engines/my-app/sessions/1'
+        ),
+        'projects/my-project/locations/us-central1/reasoningEngines/123/sessions/1',
+    ],
+)
+async def test_get_session_accepts_fully_qualified_resource_name(
+    resource_name: str,
+):
+  session_service = mock_vertex_ai_session_service()
+
+  session = await session_service.get_session(
+      app_name='123',
+      user_id='user',
+      session_id=resource_name,
+  )
+
+  assert session == MOCK_SESSION
+
+
+@pytest.mark.asyncio
+@pytest.mark.usefixtures('mock_get_api_client')
+async def test_delete_session_accepts_fully_qualified_resource_name():
+  session_service = mock_vertex_ai_session_service()
+
+  await session_service.delete_session(
+      app_name='123',
+      user_id='user',
+      session_id=(
+          'projects/my-project/locations/global/collections/default_collection/'
+          'engines/my-app/sessions/1'
+      ),
+  )
+
+  with pytest.raises(api_core_exceptions.NotFound) as excinfo:
+    await session_service.get_session(
+        app_name='123', user_id='user', session_id='1'
+    )
+  assert str(excinfo.value) == '404 Session not found: 1'
+
+
 @pytest.mark.asyncio
 @pytest.mark.usefixtures('mock_get_api_client')
 async def test_delete_session_rejects_other_users_session():
@@ -753,7 +800,15 @@ async def test_session_id_path_traversal_rejected():
   """Session IDs containing path-traversal characters must be rejected."""
   session_service = mock_vertex_ai_session_service()
 
-  for bad_id in ['..', '../foo', '..?force=true', 'a/b', '']:
+  for bad_id in [
+      '..',
+      '../foo',
+      '..?force=true',
+      'a/b',
+      '',
+      'projects/my-project/locations/global/sessions/../foo',
+      'reasoningEngines/123/sessions/1',
+  ]:
     with pytest.raises(ValueError):
       await session_service.delete_session(
           app_name='123', user_id='user', session_id=bad_id