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https://github.com/google/adk-docs.git
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Gururaj Deshpande
ff454ac1c9
* fix: change call_agent to call_agent_async * added await in storyflow where missing * updated callbacks and storyflow with await and user comment * fixed more * added licencse header --------- Co-authored-by: Lavi Nigam <98014943+lavinigam-gcp@users.noreply.github.com> Co-authored-by: Lavi Nigam <lavinigam@google.com>
108 lines
4.6 KiB
Python
108 lines
4.6 KiB
Python
# Copyright 2025 Google LLC
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from google.adk.agents import LlmAgent
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from google.adk.agents.callback_context import CallbackContext
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from google.adk.models import LlmResponse, LlmRequest
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from google.adk.runners import Runner
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from typing import Optional
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from google.genai import types
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from google.adk.sessions import InMemorySessionService
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GEMINI_2_FLASH="gemini-2.0-flash"
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# --- Define the Callback Function ---
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def simple_before_model_modifier(
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callback_context: CallbackContext, llm_request: LlmRequest
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) -> Optional[LlmResponse]:
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"""Inspects/modifies the LLM request or skips the call."""
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agent_name = callback_context.agent_name
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print(f"[Callback] Before model call for agent: {agent_name}")
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# Inspect the last user message in the request contents
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last_user_message = ""
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if llm_request.contents and llm_request.contents[-1].role == 'user':
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if llm_request.contents[-1].parts:
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last_user_message = llm_request.contents[-1].parts[0].text
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print(f"[Callback] Inspecting last user message: '{last_user_message}'")
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# --- Modification Example ---
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# Add a prefix to the system instruction
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original_instruction = llm_request.config.system_instruction or types.Content(role="system", parts=[])
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prefix = "[Modified by Callback] "
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# Ensure system_instruction is Content and parts list exists
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if not isinstance(original_instruction, types.Content):
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# Handle case where it might be a string (though config expects Content)
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original_instruction = types.Content(role="system", parts=[types.Part(text=str(original_instruction))])
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if not original_instruction.parts:
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original_instruction.parts.append(types.Part(text="")) # Add an empty part if none exist
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# Modify the text of the first part
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modified_text = prefix + (original_instruction.parts[0].text or "")
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original_instruction.parts[0].text = modified_text
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llm_request.config.system_instruction = original_instruction
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print(f"[Callback] Modified system instruction to: '{modified_text}'")
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# --- Skip Example ---
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# Check if the last user message contains "BLOCK"
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if "BLOCK" in last_user_message.upper():
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print("[Callback] 'BLOCK' keyword found. Skipping LLM call.")
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# Return an LlmResponse to skip the actual LLM call
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return LlmResponse(
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content=types.Content(
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role="model",
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parts=[types.Part(text="LLM call was blocked by before_model_callback.")],
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)
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)
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else:
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print("[Callback] Proceeding with LLM call.")
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# Return None to allow the (modified) request to go to the LLM
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return None
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# Create LlmAgent and Assign Callback
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my_llm_agent = LlmAgent(
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name="ModelCallbackAgent",
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model=GEMINI_2_FLASH,
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instruction="You are a helpful assistant.", # Base instruction
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description="An LLM agent demonstrating before_model_callback",
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before_model_callback=simple_before_model_modifier # Assign the function here
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)
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APP_NAME = "guardrail_app"
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USER_ID = "user_1"
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SESSION_ID = "session_001"
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# Session and Runner
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async def setup_session_and_runner():
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session_service = InMemorySessionService()
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session = await session_service.create_session(app_name=APP_NAME, user_id=USER_ID, session_id=SESSION_ID)
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runner = Runner(agent=my_llm_agent, app_name=APP_NAME, session_service=session_service)
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return session, runner
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# Agent Interaction
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async def call_agent_async(query):
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content = types.Content(role='user', parts=[types.Part(text=query)])
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session, runner = await setup_session_and_runner()
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events = runner.run_async(user_id=USER_ID, session_id=SESSION_ID, new_message=content)
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async for event in events:
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if event.is_final_response():
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final_response = event.content.parts[0].text
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print("Agent Response: ", final_response)
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# Note: In Colab, you can directly use 'await' at the top level.
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# If running this code as a standalone Python script, you'll need to use asyncio.run() or manage the event loop.
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await call_agent_async("write a joke on BLOCK") |