fix(tools): support regional Discovery Engine endpoints

src/google/adk/tools/discovery_engine_search_tool.py

@@ -14,6 +14,7 @@
 
 from __future__ import annotations
 
+import re
 from typing import Any
 from typing import Optional
 
@@ -25,6 +26,75 @@
 
 from .function_tool import FunctionTool
 
+_DEFAULT_ENDPOINT = "discoveryengine.googleapis.com"
+_GLOBAL_LOCATION = "global"
+_LOCATION_PATTERN = re.compile(
+    r"/locations/([a-z0-9-]+)(?:/|$)", flags=re.IGNORECASE
+)
+_VALID_LOCATION_PATTERN = re.compile(r"^[a-z0-9-]+$")
+
+
+def _normalize_location(location: str, location_type: str) -> str:
+  """Normalizes and validates a location value."""
+  normalized_location = location.strip().lower()
+  if not normalized_location:
+    raise ValueError(f"{location_type} must not be empty if specified.")
+  if not _VALID_LOCATION_PATTERN.fullmatch(normalized_location):
+    raise ValueError(
+        f"{location_type} must contain only letters, digits, and hyphens."
+    )
+  return normalized_location
+
+
+def _extract_resource_location(resource_id: str) -> Optional[str]:
+  """Extracts and validates location from a resource id."""
+  if "/locations/" not in resource_id.lower():
+    return None
+
+  location_match = _LOCATION_PATTERN.search(resource_id)
+  if not location_match:
+    raise ValueError("Invalid location in data_store_id or search_engine_id.")
+  return _normalize_location(location_match.group(1), "resource location")
+
+
+def _resolve_location(resource_id: str, location: Optional[str]) -> str:
+  """Resolves the Discovery Engine location to use for the endpoint."""
+  inferred_location = _extract_resource_location(resource_id)
+
+  if location is not None:
+    normalized_location = _normalize_location(location, "location")
+    if inferred_location and normalized_location != inferred_location:
+      raise ValueError(
+          "location must match the location in data_store_id or "
+          "search_engine_id."
+      )
+    return normalized_location
+
+  if inferred_location:
+    return inferred_location
+  return _GLOBAL_LOCATION
+
+
+def _build_client_options(
+    resource_id: str,
+    quota_project_id: Optional[str],
+    location: Optional[str],
+) -> Optional[client_options.ClientOptions]:
+  """Builds client options for Discovery Engine requests."""
+  client_options_kwargs = {}
+  resolved_location = _resolve_location(resource_id, location)
+
+  if resolved_location != _GLOBAL_LOCATION:
+    client_options_kwargs["api_endpoint"] = (
+        f"{resolved_location}-{_DEFAULT_ENDPOINT}"
+    )
+  if quota_project_id:
+    client_options_kwargs["quota_project_id"] = quota_project_id
+
+  if not client_options_kwargs:
+    return None
+  return client_options.ClientOptions(**client_options_kwargs)
+
 
 class DiscoveryEngineSearchTool(FunctionTool):
   """Tool for searching the discovery engine."""
@@ -38,6 +108,7 @@ def __init__(
       search_engine_id: Optional[str] = None,
       filter: Optional[str] = None,
       max_results: Optional[int] = None,
+      location: Optional[str] = None,
   ):
     """Initializes the DiscoveryEngineSearchTool.
 
@@ -51,6 +122,9 @@ def __init__(
         "projects/{project}/locations/{location}/collections/{collection}/engines/{engine}".
       filter: The filter to be applied to the search request. Default is None.
       max_results: The maximum number of results to return. Default is None.
+      location: Optional endpoint location override.
+        Examples: "global", "us", "eu". If not specified, location is inferred
+        from `data_store_id` or `search_engine_id` and defaults to "global".
     """
     super().__init__(self.discovery_engine_search)
     if (data_store_id is None and search_engine_id is None) or (
@@ -71,13 +145,15 @@ def __init__(
     self._search_engine_id = search_engine_id
     self._filter = filter
     self._max_results = max_results
+    self._location = location
 
     credentials, _ = google.auth.default()
     quota_project_id = getattr(credentials, "quota_project_id", None)
-    options = (
-        client_options.ClientOptions(quota_project_id=quota_project_id)
-        if quota_project_id
-        else None
+    resource_id = data_store_id or search_engine_id or ""
+    options = _build_client_options(
+        resource_id=resource_id,
+        quota_project_id=quota_project_id,
+        location=location,
     )
     self._discovery_engine_client = discoveryengine.SearchServiceClient(
         credentials=credentials, client_options=options

tests/unittests/tools/test_discovery_engine_search_tool.py

@@ -79,6 +79,193 @@ def test_init_with_data_store_specs_without_search_engine_id_raises_error(
           data_store_id="test_data_store", data_store_specs=[{"id": "123"}]
       )
 
+  @pytest.mark.parametrize(
+      ("tool_kwargs", "expected_endpoint"),
+      [
+          (
+              {
+                  "data_store_id": (
+                      "projects/test/locations/eu/collections/default_collection/"
+                      "dataStores/test_data_store"
+                  )
+              },
+              "eu-discoveryengine.googleapis.com",
+          ),
+          (
+              {
+                  "search_engine_id": (
+                      "projects/test/locations/us/collections/default_collection/"
+                      "engines/test_search_engine"
+                  )
+              },
+              "us-discoveryengine.googleapis.com",
+          ),
+          (
+              {
+                  "data_store_id": (
+                      "projects/test/locations/europe-west1/collections/"
+                      "default_collection/dataStores/test_data_store"
+                  )
+              },
+              "europe-west1-discoveryengine.googleapis.com",
+          ),
+      ],
+  )
+  @mock.patch.object(discovery_engine_search_tool, "client_options")
+  @mock.patch.object(discoveryengine, "SearchServiceClient")
+  def test_init_with_regional_location_uses_regional_endpoint(
+      self,
+      mock_search_client,
+      mock_client_options,
+      tool_kwargs,
+      expected_endpoint,
+  ):
+    """Test initialization uses the expected regional API endpoint."""
+    DiscoveryEngineSearchTool(**tool_kwargs)
+
+    mock_client_options.ClientOptions.assert_called_once_with(
+        api_endpoint=expected_endpoint
+    )
+    mock_search_client.assert_called_once_with(
+        credentials="credentials",
+        client_options=mock_client_options.ClientOptions.return_value,
+    )
+
+  @mock.patch.object(discovery_engine_search_tool, "client_options")
+  @mock.patch.object(discoveryengine, "SearchServiceClient")
+  def test_init_with_explicit_location_override_uses_input_location(
+      self, mock_search_client, mock_client_options
+  ):
+    """Test initialization uses explicit location when resource has none."""
+    DiscoveryEngineSearchTool(
+        data_store_id="test_data_store",
+        location="eu",
+    )
+
+    mock_client_options.ClientOptions.assert_called_once_with(
+        api_endpoint="eu-discoveryengine.googleapis.com"
+    )
+    mock_search_client.assert_called_once_with(
+        credentials="credentials",
+        client_options=mock_client_options.ClientOptions.return_value,
+    )
+
+  @mock.patch.object(discoveryengine, "SearchServiceClient")
+  def test_init_with_mismatched_location_raises_error(self, mock_search_client):
+    """Test initialization rejects mismatched location overrides."""
+    with pytest.raises(
+        ValueError,
+        match=(
+            "location must match the location in data_store_id or "
+            "search_engine_id."
+        ),
+    ):
+      DiscoveryEngineSearchTool(
+          data_store_id=(
+              "projects/test/locations/us/collections/default_collection/"
+              "dataStores/test_data_store"
+          ),
+          location="eu",
+      )
+
+    mock_search_client.assert_not_called()
+
+  @mock.patch.object(discoveryengine, "SearchServiceClient")
+  def test_init_with_empty_location_raises_error(self, mock_search_client):
+    """Test initialization rejects an empty location override."""
+    with pytest.raises(
+        ValueError, match="location must not be empty if specified."
+    ):
+      DiscoveryEngineSearchTool(
+          data_store_id=(
+              "projects/test/locations/us/collections/default_collection/"
+              "dataStores/test_data_store"
+          ),
+          location=" ",
+      )
+
+    mock_search_client.assert_not_called()
+
+  @mock.patch.object(discoveryengine, "SearchServiceClient")
+  def test_init_with_invalid_override_location_raises_error(
+      self, mock_search_client
+  ):
+    """Test initialization rejects invalid override location characters."""
+    with pytest.raises(
+        ValueError,
+        match="location must contain only letters, digits, and hyphens.",
+    ):
+      DiscoveryEngineSearchTool(
+          data_store_id="test_data_store",
+          location="attacker.com#",
+      )
+
+    mock_search_client.assert_not_called()
+
+  @mock.patch.object(discoveryengine, "SearchServiceClient")
+  def test_init_with_invalid_resource_location_raises_error(
+      self, mock_search_client
+  ):
+    """Test initialization rejects invalid resource location characters."""
+    with pytest.raises(
+        ValueError,
+        match="Invalid location in data_store_id or search_engine_id.",
+    ):
+      DiscoveryEngineSearchTool(
+          data_store_id=(
+              "projects/test/locations/attacker.com#/collections/"
+              "default_collection/dataStores/test_data_store"
+          )
+      )
+
+    mock_search_client.assert_not_called()
+
+  @mock.patch.object(discovery_engine_search_tool, "client_options")
+  @mock.patch.object(discoveryengine, "SearchServiceClient")
+  def test_init_with_global_location_keeps_default_endpoint(
+      self, mock_search_client, mock_client_options
+  ):
+    """Test initialization keeps default API endpoint for global location."""
+    DiscoveryEngineSearchTool(
+        data_store_id=(
+            "projects/test/locations/global/collections/default_collection/"
+            "dataStores/test_data_store"
+        )
+    )
+
+    mock_client_options.ClientOptions.assert_not_called()
+    mock_search_client.assert_called_once_with(
+        credentials="credentials", client_options=None
+    )
+
+  @mock.patch.object(discovery_engine_search_tool, "client_options")
+  @mock.patch.object(discoveryengine, "SearchServiceClient")
+  def test_init_with_regional_location_and_quota_project_id(
+      self, mock_search_client, mock_client_options
+  ):
+    """Test initialization uses endpoint and quota project id together."""
+    mock_credentials = mock.MagicMock()
+    mock_credentials.quota_project_id = "test-quota-project"
+
+    with mock.patch.object(
+        auth, "default", return_value=(mock_credentials, "project")
+    ):
+      DiscoveryEngineSearchTool(
+          data_store_id=(
+              "projects/test/locations/eu/collections/default_collection/"
+              "dataStores/test_data_store"
+          )
+      )
+
+    mock_client_options.ClientOptions.assert_called_once_with(
+        api_endpoint="eu-discoveryengine.googleapis.com",
+        quota_project_id="test-quota-project",
+    )
+    mock_search_client.assert_called_once_with(
+        credentials=mock_credentials,
+        client_options=mock_client_options.ClientOptions.return_value,
+    )
+
   @mock.patch.object(discovery_engine_search_tool, "client_options")
   @mock.patch.object(
       discoveryengine,