Google ADK 教學：從零開始打造 AI Agent 並部署至生產環境

pip install google-adk

# Set your API key (add to .bashrc/.zshrc for persistence)
export GOOGLE_API_KEY="your-api-key-here"

my_agent/
  __init__.py    # Exports root_agent
  agent.py       # Agent definition
.env             # Optional: GOOGLE_API_KEY=your-key

# my_agent/agent.py
from google.adk.agents import LlmAgent

root_agent = LlmAgent(
    name="my_assistant",
    model="gemini-2.0-flash",
    instruction="""You are a helpful coding assistant. 
    You explain concepts clearly and provide working code examples.
    Keep responses concise but thorough.""",
    description="A coding assistant that explains concepts and writes code"
)

# my_agent/__init__.py
from .agent import root_agent

# CLI mode -- chat in your terminal
adk run my_agent

# Web UI mode -- opens a browser interface
adk web my_agent

# my_agent/agent.py
from google.adk.agents import LlmAgent

def get_stock_price(ticker: str) -> dict:
    """Get the current stock price for a given ticker symbol.
    
    Args:
        ticker: The stock ticker symbol (e.g., 'AAPL', 'GOOGL', 'MSFT')
    
    Returns:
        A dictionary with the ticker and its current price.
    """
    # In production, you'd call a real API here
    mock_prices = {"AAPL": 198.50, "GOOGL": 175.20, "MSFT": 425.80}
    price = mock_prices.get(ticker.upper(), None)
    if price:
        return {"ticker": ticker.upper(), "price": price, "currency": "USD"}
    return {"error": f"Ticker {ticker} not found"}

root_agent = LlmAgent(
    name="finance_assistant",
    model="gemini-2.0-flash",
    instruction="You help users check stock prices. Use the get_stock_price tool when asked about any stock.",
    tools=[get_stock_price],
    description="A financial assistant that looks up stock prices"
)

from google.adk.agents import LlmAgent
from google.adk.tools import google_search, code_execution

root_agent = LlmAgent(
    name="research_agent",
    model="gemini-2.0-flash",
    instruction="You research topics using Google Search and can run Python code to analyze data.",
    tools=[google_search, code_execution],
    description="A research agent with search and code execution capabilities"
)

from google.adk.agents import LlmAgent
from google.adk.tools import google_search

# Sub-agent 1: handles research
research_agent = LlmAgent(
    name="researcher",
    model="gemini-2.0-flash",
    instruction="You research topics thoroughly using Google Search. Return factual, well-sourced information.",
    tools=[google_search],
    description="Researches topics and returns factual information"
)

# Sub-agent 2: handles writing
writing_agent = LlmAgent(
    name="writer",
    model="gemini-2.0-flash",
    instruction="You write clear, engaging content based on provided information. Focus on readability and accuracy.",
    description="Writes polished content from research notes"
)

# Root agent: delegates to the right sub-agent
root_agent = LlmAgent(
    name="content_manager",
    model="gemini-2.0-flash",
    instruction="""You manage content creation. 
    - When the user wants information gathered, delegate to the researcher.
    - When the user wants content written or edited, delegate to the writer.
    - You can chain both: research first, then write.""",
    sub_agents=[research_agent, writing_agent],
    description="Manages content creation by delegating to research and writing specialists"
)

from google.adk.tools import agent_tool

research_tool = agent_tool.AgentTool(agent=research_agent)

root_agent = LlmAgent(
    name="writer_with_research",
    model="gemini-2.0-flash",
    instruction="You write articles. Use the research tool to gather facts before writing.",
    tools=[research_tool],
    description="A writer that can research topics on demand"
)

from google.adk.agents import SequentialAgent, ParallelAgent, LlmAgent

# Three agents that must run in order
research_agent = LlmAgent(name="researcher", model="gemini-2.0-flash",
    instruction="Research the given topic.", description="Researches topics")
    
draft_agent = LlmAgent(name="drafter", model="gemini-2.0-flash",
    instruction="Write a draft based on the research.", description="Writes drafts")
    
review_agent = LlmAgent(name="reviewer", model="gemini-2.0-flash",
    instruction="Review the draft for accuracy and clarity.", description="Reviews content")

# Pipeline: research -> draft -> review
content_pipeline = SequentialAgent(
    name="content_pipeline",
    sub_agents=[research_agent, draft_agent, review_agent],
    description="Runs a complete content creation pipeline"
)

# Three data fetchers that run concurrently
fetch_news = LlmAgent(name="news_fetcher", model="gemini-2.0-flash",
    instruction="Fetch latest tech news.", description="Fetches news")
    
fetch_stocks = LlmAgent(name="stock_fetcher", model="gemini-2.0-flash",
    instruction="Fetch stock market summary.", description="Fetches stocks")
    
fetch_weather = LlmAgent(name="weather_fetcher", model="gemini-2.0-flash",
    instruction="Fetch weather forecast.", description="Fetches weather")

morning_briefing = ParallelAgent(
    name="morning_briefing",
    sub_agents=[fetch_news, fetch_stocks, fetch_weather],
    description="Gathers morning briefing data in parallel"
)

from google.adk.agents import LlmAgent

def save_preference(key: str, value: str, context) -> str:
    """Save a user preference to session state.
    
    Args:
        key: The preference name (e.g., 'language', 'theme')
        value: The preference value
        context: The ADK context object
    
    Returns:
        Confirmation message
    """
    context.state[key] = value
    return f"Saved preference: {key} = {value}"

def get_preference(key: str, context) -> str:
    """Retrieve a user preference from session state.
    
    Args:
        key: The preference name to look up
        context: The ADK context object
    
    Returns:
        The preference value or a not-found message
    """
    value = context.state.get(key, "Not set")
    return f"{key} = {value}"

root_agent = LlmAgent(
    name="personalized_assistant",
    model="gemini-2.0-flash",
    instruction="You remember user preferences. Save them when told, recall them when asked.",
    tools=[save_preference, get_preference],
    description="An assistant that remembers user preferences"
)

from google.adk.memory import InMemoryMemoryService

# For development (data lost on restart)
memory_service = InMemoryMemoryService()

# For production, use VertexAIMemoryBankService
# memory_service = VertexAIMemoryBankService(project="your-project")

from google.adk.agents import LlmAgent

def safety_filter(callback_context, llm_request):
    """Block requests containing harmful content patterns."""
    user_message = str(llm_request)
    blocked_patterns = ["ignore your instructions", "pretend you are"]
    
    for pattern in blocked_patterns:
        if pattern.lower() in user_message.lower():
            # Return a response directly, skipping the model call
            return {"blocked": True, "reason": "Request matched safety filter"}
    
    # Return None to proceed normally
    return None

def log_tool_usage(callback_context, tool_name, tool_result):
    """Log every tool call for monitoring."""
    print(f"[TOOL LOG] {tool_name}: {tool_result}")
    return None  # Don't modify the result

root_agent = LlmAgent(
    name="safe_assistant",
    model="gemini-2.0-flash",
    instruction="You are a helpful assistant.",
    before_model_callback=safety_filter,
    after_tool_callback=log_tool_usage,
    description="A safety-filtered assistant with tool logging"
)

[
  {
    "input": "What's the stock price of AAPL?",
    "expected_output": "198.50",
    "expected_trajectory": [
      {"tool_name": "get_stock_price", "args": {"ticker": "AAPL"}}
    ]
  },
  {
    "input": "Compare AAPL and GOOGL prices",
    "expected_output": "AAPL.*198.*GOOGL.*175",
    "expected_trajectory": [
      {"tool_name": "get_stock_price", "args": {"ticker": "AAPL"}},
      {"tool_name": "get_stock_price", "args": {"ticker": "GOOGL"}}
    ]
  }
]

# test_agent.py
import pytest
from google.adk.evaluation import ResponseEvaluator, TrajectoryEvaluator

def test_stock_agent_response():
    evaluator = ResponseEvaluator(agent=root_agent)
    results = evaluator.evaluate("test_cases.json")
    
    assert results.pass_rate >= 0.8, f"Response pass rate too low: {results.pass_rate}"

def test_stock_agent_trajectory():
    evaluator = TrajectoryEvaluator(agent=root_agent)
    results = evaluator.evaluate("test_cases.json")
    
    assert results.pass_rate >= 0.9, f"Trajectory pass rate too low: {results.pass_rate}"

adk deploy cloud_run \
  --project your-gcp-project-id \
  --region us-central1 \
  --service-name my-agent-service \
  --with_ui

FROM python:3.11-slim
WORKDIR /app
COPY requirements.txt .
RUN pip install -r requirements.txt
COPY . .
EXPOSE 8080
CMD ["adk", "api_server", "--port", "8080", "my_agent"]