fix: merge tracking headers even when llm_request.config.http_options is not set in Gemini.generate_content_async

src/google/adk/models/google_llm.py

@@ -116,9 +116,12 @@ async def generate_content_async(
     )
     logger.debug(_build_request_log(llm_request))
 
-    # add tracking headers to custom headers given it will override the headers
-    # set in the api client constructor
-    if llm_request.config and llm_request.config.http_options:
+    # Always add tracking headers to custom headers given it will override
+    # the headers set in the api client constructor to avoid tracking headers
+    # being dropped if user provides custom headers or overrides the api client.
+    if llm_request.config:
+      if not llm_request.config.http_options:
+        llm_request.config.http_options = types.HttpOptions()
       if not llm_request.config.http_options.headers:
         llm_request.config.http_options.headers = {}
       llm_request.config.http_options.headers.update(self._tracking_headers)

tests/unittests/models/test_google_llm.py

@@ -27,12 +27,27 @@
 from google.adk.models.llm_response import LlmResponse
 from google.adk.utils.variant_utils import GoogleLLMVariant
 from google.genai import types
-from google.genai import version as genai_version
 from google.genai.types import Content
 from google.genai.types import Part
 import pytest
 
 
+class MockAsyncIterator:
+  """Mock for async iterator."""
+
+  def __init__(self, seq):
+    self.iter = iter(seq)
+
+  def __aiter__(self):
+    return self
+
+  async def __anext__(self):
+    try:
+      return next(self.iter)
+    except StopIteration as exc:
+      raise StopAsyncIteration from exc
+
+
 @pytest.fixture
 def generate_content_response():
   return types.GenerateContentResponse(
@@ -215,21 +230,6 @@ async def mock_coro():
 @pytest.mark.asyncio
 async def test_generate_content_async_stream(gemini_llm, llm_request):
   with mock.patch.object(gemini_llm, "api_client") as mock_client:
-    # Create mock stream responses
-    class MockAsyncIterator:
-
-      def __init__(self, seq):
-        self.iter = iter(seq)
-
-      def __aiter__(self):
-        return self
-
-      async def __anext__(self):
-        try:
-          return next(self.iter)
-        except StopIteration:
-          raise StopAsyncIteration
-
     mock_responses = [
         types.GenerateContentResponse(
             candidates=[
@@ -292,21 +292,6 @@ async def test_generate_content_async_stream_preserves_thinking_and_text_parts(
     gemini_llm, llm_request
 ):
   with mock.patch.object(gemini_llm, "api_client") as mock_client:
-
-    class MockAsyncIterator:
-
-      def __init__(self, seq):
-        self._iter = iter(seq)
-
-      def __aiter__(self):
-        return self
-
-      async def __anext__(self):
-        try:
-          return next(self._iter)
-        except StopIteration:
-          raise StopAsyncIteration
-
     response1 = types.GenerateContentResponse(
         candidates=[
             types.Candidate(
@@ -436,21 +421,6 @@ async def test_generate_content_async_stream_with_custom_headers(
   llm_request.config.http_options = types.HttpOptions(headers=custom_headers)
 
   with mock.patch.object(gemini_llm, "api_client") as mock_client:
-    # Create mock stream responses
-    class MockAsyncIterator:
-
-      def __init__(self, seq):
-        self.iter = iter(seq)
-
-      def __aiter__(self):
-        return self
-
-      async def __anext__(self):
-        try:
-          return next(self.iter)
-        except StopIteration:
-          raise StopAsyncIteration
-
     mock_responses = [
         types.GenerateContentResponse(
             candidates=[
@@ -488,35 +458,58 @@ async def mock_coro():
     assert len(responses) == 2
 
 
+@pytest.mark.parametrize("stream", [True, False])
 @pytest.mark.asyncio
-async def test_generate_content_async_without_custom_headers(
-    gemini_llm, llm_request, generate_content_response
+async def test_generate_content_async_patches_tracking_headers(
+    stream, gemini_llm, llm_request, generate_content_response
 ):
-  """Test that tracking headers are not modified when no custom headers exist."""
-  # Ensure no http_options exist initially
+  """Tests that tracking headers are added to the request config."""
+  # Set the request's config.http_options to None.
   llm_request.config.http_options = None
 
   with mock.patch.object(gemini_llm, "api_client") as mock_client:
+    if stream:
+      # Create a mock coroutine that returns the mock_responses.
+      async def mock_coro():
+        return MockAsyncIterator([generate_content_response])
 
-    async def mock_coro():
-      return generate_content_response
+      # Mock for streaming response.
+      mock_client.aio.models.generate_content_stream.return_value = mock_coro()
+    else:
+      # Create a mock coroutine that returns the generate_content_response.
+      async def mock_coro():
+        return generate_content_response
 
-    mock_client.aio.models.generate_content.return_value = mock_coro()
+      # Mock for non-streaming response.
+      mock_client.aio.models.generate_content.return_value = mock_coro()
 
+    # Call the generate_content_async method.
     responses = [
         resp
         async for resp in gemini_llm.generate_content_async(
-            llm_request, stream=False
+            llm_request, stream=stream
         )
     ]
 
-    # Verify that the config passed to generate_content has no http_options
-    mock_client.aio.models.generate_content.assert_called_once()
-    call_args = mock_client.aio.models.generate_content.call_args
-    config_arg = call_args.kwargs["config"]
-    assert config_arg.http_options is None
+    # Assert that the config passed to the generate_content or
+    # generate_content_stream method contains the tracking headers.
+    if stream:
+      mock_client.aio.models.generate_content_stream.assert_called_once()
+      call_args = mock_client.aio.models.generate_content_stream.call_args
+    else:
+      mock_client.aio.models.generate_content.assert_called_once()
+      call_args = mock_client.aio.models.generate_content.call_args
 
-    assert len(responses) == 1
+    final_config = call_args.kwargs["config"]
+
+    assert final_config is not None
+    assert final_config.http_options is not None
+    assert (
+        final_config.http_options.headers["x-goog-api-client"]
+        == gemini_llm._tracking_headers["x-goog-api-client"]
+    )
+
+    assert len(responses) == 2 if stream else 1
 
 
 def test_live_api_version_vertex_ai(gemini_llm):
@@ -665,8 +658,7 @@ async def test_preprocess_request_handles_backend_specific_fields(
     expected_inline_display_name: Optional[str],
     expected_labels: Optional[str],
 ):
-  """
-  Tests that _preprocess_request correctly sanitizes fields based on the API backend.
+  """Tests that _preprocess_request correctly sanitizes fields based on the API backend.
 
   - For GEMINI_API, it should remove 'display_name' from file/inline data
     and remove 'labels' from the config.
@@ -732,21 +724,6 @@ async def test_generate_content_async_stream_aggregated_content_regardless_of_fi
   )
 
   with mock.patch.object(gemini_llm, "api_client") as mock_client:
-
-    class MockAsyncIterator:
-
-      def __init__(self, seq):
-        self.iter = iter(seq)
-
-      def __aiter__(self):
-        return self
-
-      async def __anext__(self):
-        try:
-          return next(self.iter)
-        except StopIteration:
-          raise StopAsyncIteration
-
     # Test with different finish reasons
     test_cases = [
         types.FinishReason.MAX_TOKENS,
@@ -820,21 +797,6 @@ async def test_generate_content_async_stream_with_thought_and_text_error_handlin
   )
 
   with mock.patch.object(gemini_llm, "api_client") as mock_client:
-
-    class MockAsyncIterator:
-
-      def __init__(self, seq):
-        self.iter = iter(seq)
-
-      def __aiter__(self):
-        return self
-
-      async def __anext__(self):
-        try:
-          return next(self.iter)
-        except StopIteration:
-          raise StopAsyncIteration
-
     mock_responses = [
         types.GenerateContentResponse(
             candidates=[
@@ -902,21 +864,6 @@ async def test_generate_content_async_stream_error_info_none_for_stop_finish_rea
   )
 
   with mock.patch.object(gemini_llm, "api_client") as mock_client:
-
-    class MockAsyncIterator:
-
-      def __init__(self, seq):
-        self.iter = iter(seq)
-
-      def __aiter__(self):
-        return self
-
-      async def __anext__(self):
-        try:
-          return next(self.iter)
-        except StopIteration:
-          raise StopAsyncIteration
-
     mock_responses = [
         types.GenerateContentResponse(
             candidates=[
@@ -980,21 +927,6 @@ async def test_generate_content_async_stream_error_info_set_for_non_stop_finish_
   )
 
   with mock.patch.object(gemini_llm, "api_client") as mock_client:
-
-    class MockAsyncIterator:
-
-      def __init__(self, seq):
-        self.iter = iter(seq)
-
-      def __aiter__(self):
-        return self
-
-      async def __anext__(self):
-        try:
-          return next(self.iter)
-        except StopIteration:
-          raise StopAsyncIteration
-
     mock_responses = [
         types.GenerateContentResponse(
             candidates=[
@@ -1058,21 +990,6 @@ async def test_generate_content_async_stream_no_aggregated_content_without_text(
   )
 
   with mock.patch.object(gemini_llm, "api_client") as mock_client:
-
-    class MockAsyncIterator:
-
-      def __init__(self, seq):
-        self.iter = iter(seq)
-
-      def __aiter__(self):
-        return self
-
-      async def __anext__(self):
-        try:
-          return next(self.iter)
-        except StopIteration:
-          raise StopAsyncIteration
-
     # Mock response with no text content
     mock_responses = [
         types.GenerateContentResponse(
@@ -1127,21 +1044,6 @@ async def test_generate_content_async_stream_mixed_text_function_call_text():
   )
 
   with mock.patch.object(gemini_llm, "api_client") as mock_client:
-
-    class MockAsyncIterator:
-
-      def __init__(self, seq):
-        self.iter = iter(seq)
-
-      def __aiter__(self):
-        return self
-
-      async def __anext__(self):
-        try:
-          return next(self.iter)
-        except StopIteration:
-          raise StopAsyncIteration
-
     # Create responses with pattern: text -> function_call -> text
     mock_responses = [
         # First text chunk
@@ -1247,21 +1149,6 @@ async def test_generate_content_async_stream_multiple_text_parts_in_single_respo
   )
 
   with mock.patch.object(gemini_llm, "api_client") as mock_client:
-
-    class MockAsyncIterator:
-
-      def __init__(self, seq):
-        self.iter = iter(seq)
-
-      def __aiter__(self):
-        return self
-
-      async def __anext__(self):
-        try:
-          return next(self.iter)
-        except StopIteration:
-          raise StopAsyncIteration
-
     # Create a response with multiple text parts
     mock_responses = [
         types.GenerateContentResponse(
@@ -1314,21 +1201,6 @@ async def test_generate_content_async_stream_complex_mixed_thought_text_function
   )
 
   with mock.patch.object(gemini_llm, "api_client") as mock_client:
-
-    class MockAsyncIterator:
-
-      def __init__(self, seq):
-        self.iter = iter(seq)
-
-      def __aiter__(self):
-        return self
-
-      async def __anext__(self):
-        try:
-          return next(self.iter)
-        except StopIteration:
-          raise StopAsyncIteration
-
     # Complex pattern: thought -> text -> function_call -> thought -> text
     mock_responses = [
         # Thought
@@ -1450,21 +1322,6 @@ async def test_generate_content_async_stream_two_separate_text_aggregations():
   )
 
   with mock.patch.object(gemini_llm, "api_client") as mock_client:
-
-    class MockAsyncIterator:
-
-      def __init__(self, seq):
-        self.iter = iter(seq)
-
-      def __aiter__(self):
-        return self
-
-      async def __anext__(self):
-        try:
-          return next(self.iter)
-        except StopIteration:
-          raise StopAsyncIteration
-
     # Create responses: multiple text chunks -> function_call -> multiple text chunks
     mock_responses = [
         # First text accumulation (multiple chunks)