fix: redact credentials from generate_content_config.http_options in debug logs

Merge https://github.com/google/adk-python/pull/6546

PiperOrigin-RevId: 967026896

src/google/adk/models/google_llm.py

@@ -717,14 +717,28 @@ def _build_request_log(req: LlmRequest) -> str:
             exclude={
                 'system_instruction': True,
                 'tools': tools_exclusion if req.config.tools else True,
-                # Callers may put credentials in per-request headers, so the
-                # transport options never go to the log.
-                'http_options': True,
+                # `http_options` carries caller-supplied credentials:
+                # `headers` commonly holds an Authorization bearer token,
+                # and `extra_body` / `*client_args` are free-form
+                # passthroughs that can hold auth material too. None of
+                # it may reach a debug log. Mirrors the same exclusion
+                # applied to trace spans in telemetry/tracing.py.
+                'http_options': {
+                    'httpx_client': True,
+                    'httpx_async_client': True,
+                    'aiohttp_client': True,
+                    'headers': True,
+                    'extra_body': True,
+                    'client_args': True,
+                    'async_client_args': True,
+                },
             },
         )
     )
   except Exception:
-    config_log = repr(req.config.model_copy(update={'http_options': None}))
+    # Do not fall back to repr(req.config) here: an unredacted repr would
+    # reintroduce the same credential leak this function exists to avoid.
+    config_log = '<error building config log>'
 
   return f"""
 LLM Request:

tests/unittests/models/test_google_llm.py

@@ -2563,7 +2563,7 @@ def test_build_request_log_function_declarations_in_second_tool():
 
 
 def test_build_request_log_fallback_to_repr_on_all_failures(monkeypatch):
-  """Test that _build_request_log falls back to repr() if model_dump fails."""
+  """Test that _build_request_log falls back to placeholder if model_dump fails."""
 
   llm_request = LlmRequest(
       model="gemini-2.5-flash",
@@ -2584,9 +2584,45 @@ def test_build_request_log_fallback_to_repr_on_all_failures(monkeypatch):
 
   log_output = _build_request_log(llm_request)
 
-  # Should still succeed using repr()
+  # Should still succeed using the placeholder
   assert "Config:" in log_output
-  assert "GenerateContentConfig" in log_output
+  assert "<error building config log>" in log_output
+
+
+def test_build_request_log_redacts_http_options_credentials():
+  """Test that _build_request_log redacts sensitive fields in http_options."""
+  llm_request = LlmRequest(
+      model="gemini-2.5-flash",
+      contents=[Content(role="user", parts=[Part.from_text(text="Hello")])],
+      config=types.GenerateContentConfig(
+          temperature=0.7,
+          http_options=types.HttpOptions(
+              headers={"Authorization": "Bearer secret_token"},
+              extra_body={"secret_key": "some_secret"},
+              client_args={"token": "arg_secret"},
+              async_client_args={"token": "async_secret"},
+              base_url="https://example.com/api",
+          ),
+      ),
+  )
+
+  log_output = _build_request_log(llm_request)
+
+  assert "Config:" in log_output
+  # base_url should be present
+  assert "https://example.com/api" in log_output
+  # sensitive http_options fields should NOT be present in log_output
+  assert "secret_token" not in log_output
+  assert "secret_key" not in log_output
+  assert "arg_secret" not in log_output
+  assert "async_secret" not in log_output
+  assert "'headers'" not in log_output
+  assert "'extra_body'" not in log_output
+  assert "'client_args'" not in log_output
+  assert "'async_client_args'" not in log_output
+  assert "'httpx_client'" not in log_output
+  assert "'httpx_async_client'" not in log_output
+  assert "'aiohttp_client'" not in log_output
 
 
 @pytest.mark.asyncio