chore: import upstream snapshot with attribution

contributing/samples/workflows/auth_api_key/agent.py

@@ -0,0 +1,83 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Auth API Key sample: FunctionNode with API key authentication.
+
+Demonstrates how to use `auth_config` on a FunctionNode to pause
+the workflow and request user credentials before running the node.
+
+Flow:
+  1. User sends any message to start the workflow.
+  2. The `fetch_weather` node pauses and requests an API key.
+  3. The user provides the API key through the auth UI.
+  4. The node runs with the credential available in session state.
+  5. The `summarize` node displays the result.
+"""
+
+from fastapi.openapi.models import APIKey
+from fastapi.openapi.models import APIKeyIn
+from google.adk import Event
+from google.adk import Workflow
+from google.adk.agents.context import Context
+from google.adk.auth.auth_credential import AuthCredential
+from google.adk.auth.auth_credential import AuthCredentialTypes
+from google.adk.auth.auth_tool import AuthConfig
+from google.adk.workflow import node
+
+# --- Auth configuration ---
+# Uses API key auth: the simplest credential type.
+# The user will be prompted to provide an API key via the auth UI.
+auth_config = AuthConfig(
+    auth_scheme=APIKey(**{'in': APIKeyIn.header, 'name': 'X-Api-Key'}),
+    raw_auth_credential=AuthCredential(
+        auth_type=AuthCredentialTypes.API_KEY,
+        api_key='placeholder',
+    ),
+    credential_key='weather_api_key',
+)
+
+
+@node(auth_config=auth_config, rerun_on_resume=True)
+def fetch_weather(ctx: Context):
+  """Fetches weather data using the authenticated API key."""
+  # After auth completes, the credential is available via ctx.
+  cred = ctx.get_auth_response(auth_config)
+  api_key = cred.api_key if cred else 'unknown'
+
+  # In a real agent, you would use the api_key to call an external API.
+  # For this sample, we just echo it back (masked).
+  masked = api_key[:4] + '****' if len(api_key) > 4 else '****'
+  return {
+      'city': 'San Francisco',
+      'temperature': '18C',
+      'condition': 'Sunny',
+      'api_key_used': masked,
+  }
+
+
+def summarize(node_input: dict):
+  """Displays the weather result."""
+  yield Event(
+      message=(
+          f"Weather for {node_input['city']}:"
+          f" {node_input['temperature']}, {node_input['condition']}."
+          f" (Authenticated with key: {node_input['api_key_used']})"
+      )
+  )
+
+
+root_agent = Workflow(
+    name='auth_api_key',
+    edges=[('START', fetch_weather, summarize)],
+)