如何使用Postgres检查点器进行持久化¶
在创建LangGraph代理时，您可以设置它们以持久化其状态。这允许您多次与代理交互，并使其记住之前的交互。
本操作指南展示了如何使用Postgres作为持久化检查点状态的后端，使用langgraph-checkpoint-postgres库。
为了演示目的，我们将在预构建的React代理中添加持久化。
一般来说，您可以像下面这样为任何自定义图添加检查点器：
from langgraph.graph import StateGraph
builder = StateGraph(....)
# ... 定义图
checkpointer = # postgres 检查点器（见下面示例）
graph = builder.compile(checkpointer=checkpointer)
...
设置
您需要在检查点器上运行一次.setup()以初始化数据库，然后才能使用它。
环境搭建¶
你需要访问一个Postgres实例。网上有许多资源可以帮助你设置Postgres实例。
接下来，我们将安装所需的软件包并设置API密钥
import getpass
import os
def _set_env(var: str):
if not os.environ.get(var):
os.environ[var] = getpass.getpass(f"{var}: ")
_set_env("OPENAI_API_KEY")
为LangGraph开发设置LangSmith
注册LangSmith，可以快速发现并解决您的LangGraph项目中的问题，提高项目性能。LangSmith允许您使用跟踪数据来调试、测试和监控使用LangGraph构建的LLM应用程序——更多关于如何开始的信息，请参阅这里。
定义图的模型和工具¶
from typing import Literal
from langchain_core.tools import tool
from langchain_openai import ChatOpenAI
from langgraph.prebuilt import create_react_agent
from langgraph.checkpoint.postgres import PostgresSaver
from langgraph.checkpoint.postgres.aio import AsyncPostgresSaver
@tool
def get_weather(city: Literal["nyc", "sf"]):
"""Use this to get weather information."""
if city == "nyc":
return "It might be cloudy in nyc"
elif city == "sf":
return "It's always sunny in sf"
else:
raise AssertionError("Unknown city")
tools = [get_weather]
model = ChatOpenAI(model_name="gpt-4o-mini", temperature=0)
API Reference: tool | ChatOpenAI | create_react_agent
使用同步连接¶
这将设置与数据库的同步连接。
同步连接以阻塞方式执行操作，这意味着每个操作都必须等待完成才能进行下一个操作。DB_URI 是数据库连接 URI，用于连接到 PostgreSQL 数据库的协议、认证和数据库运行的主机。connection_kwargs 字典定义了数据库连接的其他参数。
使用连接池¶
这管理了一个可重用数据库连接的池： - 优点：高效利用资源，频繁连接时性能提升 - 最适合：具有许多短生命周期数据库操作的应用程序
from psycopg_pool import ConnectionPool
with ConnectionPool(
# Example configuration
conninfo=DB_URI,
max_size=20,
kwargs=connection_kwargs,
) as pool:
checkpointer = PostgresSaver(pool)
# NOTE: you need to call .setup() the first time you're using your checkpointer
checkpointer.setup()
graph = create_react_agent(model, tools=tools, checkpointer=checkpointer)
config = {"configurable": {"thread_id": "1"}}
res = graph.invoke({"messages": [("human", "what's the weather in sf")]}, config)
checkpoint = checkpointer.get(config)
{'messages': [HumanMessage(content="what's the weather in sf", id='735b7deb-b0fe-4ad5-8920-2a3c69bbe9f7'),
AIMessage(content='', additional_kwargs={'tool_calls': [{'id': 'call_lJHMDYgfgRdiEAGfFsEhqqKV', 'function': {'arguments': '{"city":"sf"}', 'name': 'get_weather'}, 'type': 'function'}]}, response_metadata={'token_usage': {'completion_tokens': 14, 'prompt_tokens': 57, 'total_tokens': 71}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_48196bc67a', 'finish_reason': 'tool_calls', 'logprobs': None}, id='run-c56b3e04-08a9-4a59-b3f5-ee52d0ef0656-0', tool_calls=[{'name': 'get_weather', 'args': {'city': 'sf'}, 'id': 'call_lJHMDYgfgRdiEAGfFsEhqqKV', 'type': 'tool_call'}], usage_metadata={'input_tokens': 57, 'output_tokens': 14, 'total_tokens': 71}),
ToolMessage(content="It's always sunny in sf", name='get_weather', id='0644bf7b-4d1b-4ebe-afa1-d2169ccce582', tool_call_id='call_lJHMDYgfgRdiEAGfFsEhqqKV'),
AIMessage(content='The weather in San Francisco is always sunny!', response_metadata={'token_usage': {'completion_tokens': 10, 'prompt_tokens': 84, 'total_tokens': 94}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_48196bc67a', 'finish_reason': 'stop', 'logprobs': None}, id='run-1ed9b8d0-9b50-4b87-b3a2-9860f51e9fd1-0', usage_metadata={'input_tokens': 84, 'output_tokens': 10, 'total_tokens': 94})]}
{'v': 1,
'id': '1ef559b7-3b19-6ce8-8003-18d0f60634be',
'ts': '2024-08-08T15:32:42.108605+00:00',
'current_tasks': {},
'pending_sends': [],
'versions_seen': {'agent': {'tools': '00000000000000000000000000000004.022986cd20ae85c77ea298a383f69ba8',
'start:agent': '00000000000000000000000000000002.d6f25946c3108fc12f27abbcf9b4cedc'},
'tools': {'branch:agent:should_continue:tools': '00000000000000000000000000000003.065d90dd7f7cd091f0233855210bb2af'},
'__input__': {},
'__start__': {'__start__': '00000000000000000000000000000001.ab89befb52cc0e91e106ef7f500ea033'}},
'channel_versions': {'agent': '00000000000000000000000000000005.065d90dd7f7cd091f0233855210bb2af',
'tools': '00000000000000000000000000000005.',
'messages': '00000000000000000000000000000005.b9adc75836c78af94af1d6811340dd13',
'__start__': '00000000000000000000000000000002.',
'start:agent': '00000000000000000000000000000003.',
'branch:agent:should_continue:tools': '00000000000000000000000000000004.'},
'channel_values': {'agent': 'agent',
'messages': [HumanMessage(content="what's the weather in sf", id='735b7deb-b0fe-4ad5-8920-2a3c69bbe9f7'),
AIMessage(content='', additional_kwargs={'tool_calls': [{'id': 'call_lJHMDYgfgRdiEAGfFsEhqqKV', 'function': {'arguments': '{"city":"sf"}', 'name': 'get_weather'}, 'type': 'function'}]}, response_metadata={'token_usage': {'completion_tokens': 14, 'prompt_tokens': 57, 'total_tokens': 71}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_48196bc67a', 'finish_reason': 'tool_calls', 'logprobs': None}, id='run-c56b3e04-08a9-4a59-b3f5-ee52d0ef0656-0', tool_calls=[{'name': 'get_weather', 'args': {'city': 'sf'}, 'id': 'call_lJHMDYgfgRdiEAGfFsEhqqKV', 'type': 'tool_call'}], usage_metadata={'input_tokens': 57, 'output_tokens': 14, 'total_tokens': 71}),
ToolMessage(content="It's always sunny in sf", name='get_weather', id='0644bf7b-4d1b-4ebe-afa1-d2169ccce582', tool_call_id='call_lJHMDYgfgRdiEAGfFsEhqqKV'),
AIMessage(content='The weather in San Francisco is always sunny!', response_metadata={'token_usage': {'completion_tokens': 10, 'prompt_tokens': 84, 'total_tokens': 94}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_48196bc67a', 'finish_reason': 'stop', 'logprobs': None}, id='run-1ed9b8d0-9b50-4b87-b3a2-9860f51e9fd1-0', usage_metadata={'input_tokens': 84, 'output_tokens': 10, 'total_tokens': 94})]}}
建立连接¶
这将创建一个单个的、专用的数据库连接： - 优点：使用简单，适合长时间的事务 - 最适合：具有较少且持续时间较长的数据库操作的应用程序
from psycopg import Connection
with Connection.connect(DB_URI, **connection_kwargs) as conn:
checkpointer = PostgresSaver(conn)
# NOTE: you need to call .setup() the first time you're using your checkpointer
# checkpointer.setup()
graph = create_react_agent(model, tools=tools, checkpointer=checkpointer)
config = {"configurable": {"thread_id": "2"}}
res = graph.invoke({"messages": [("human", "what's the weather in sf")]}, config)
checkpoint_tuple = checkpointer.get_tuple(config)
CheckpointTuple(config={'configurable': {'thread_id': '2', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-4650-6bfc-8003-1c5488f19318'}}, checkpoint={'v': 1, 'id': '1ef559b7-4650-6bfc-8003-1c5488f19318', 'ts': '2024-08-08T15:32:43.284551+00:00', 'current_tasks': {}, 'pending_sends': [], 'versions_seen': {'agent': {'tools': '00000000000000000000000000000004.022986cd20ae85c77ea298a383f69ba8', 'start:agent': '00000000000000000000000000000002.d6f25946c3108fc12f27abbcf9b4cedc'}, 'tools': {'branch:agent:should_continue:tools': '00000000000000000000000000000003.065d90dd7f7cd091f0233855210bb2af'}, '__input__': {}, '__start__': {'__start__': '00000000000000000000000000000001.ab89befb52cc0e91e106ef7f500ea033'}}, 'channel_versions': {'agent': '00000000000000000000000000000005.065d90dd7f7cd091f0233855210bb2af', 'tools': '00000000000000000000000000000005.', 'messages': '00000000000000000000000000000005.af9f229d2c4e14f4866eb37f72ec39f6', '__start__': '00000000000000000000000000000002.', 'start:agent': '00000000000000000000000000000003.', 'branch:agent:should_continue:tools': '00000000000000000000000000000004.'}, 'channel_values': {'agent': 'agent', 'messages': [HumanMessage(content="what's the weather in sf", id='7a14f96c-2d88-454f-9520-0e0287a4abbb'), AIMessage(content='', additional_kwargs={'tool_calls': [{'id': 'call_NcL4dBTYu4kSPGMKdxztdpjN', 'function': {'arguments': '{"city":"sf"}', 'name': 'get_weather'}, 'type': 'function'}]}, response_metadata={'token_usage': {'completion_tokens': 14, 'prompt_tokens': 57, 'total_tokens': 71}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_48196bc67a', 'finish_reason': 'tool_calls', 'logprobs': None}, id='run-39adbf2c-36ef-40f6-9cad-8e1f8167fc19-0', tool_calls=[{'name': 'get_weather', 'args': {'city': 'sf'}, 'id': 'call_NcL4dBTYu4kSPGMKdxztdpjN', 'type': 'tool_call'}], usage_metadata={'input_tokens': 57, 'output_tokens': 14, 'total_tokens': 71}), ToolMessage(content="It's always sunny in sf", name='get_weather', id='c9f82354-3225-40a8-bf54-81f3e199043b', tool_call_id='call_NcL4dBTYu4kSPGMKdxztdpjN'), AIMessage(content='The weather in San Francisco is always sunny!', response_metadata={'token_usage': {'completion_tokens': 10, 'prompt_tokens': 84, 'total_tokens': 94}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_48196bc67a', 'finish_reason': 'stop', 'logprobs': None}, id='run-83888be3-d681-42ca-ad67-e2f5ee8550de-0', usage_metadata={'input_tokens': 84, 'output_tokens': 10, 'total_tokens': 94})]}}, metadata={'step': 3, 'source': 'loop', 'writes': {'agent': {'messages': [AIMessage(content='The weather in San Francisco is always sunny!', response_metadata={'logprobs': None, 'model_name': 'gpt-4o-mini-2024-07-18', 'token_usage': {'total_tokens': 94, 'prompt_tokens': 84, 'completion_tokens': 10}, 'finish_reason': 'stop', 'system_fingerprint': 'fp_48196bc67a'}, id='run-83888be3-d681-42ca-ad67-e2f5ee8550de-0', usage_metadata={'input_tokens': 84, 'output_tokens': 10, 'total_tokens': 94})]}}}, parent_config={'configurable': {'thread_id': '2', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-4087-681a-8002-88a5738f76f1'}}, pending_writes=[])
使用连接字符串¶
这将基于连接字符串创建连接： - 优点：简单，封装连接细节 - 最适合：快速设置或当连接细节以字符串形式提供时
with PostgresSaver.from_conn_string(DB_URI) as checkpointer:
graph = create_react_agent(model, tools=tools, checkpointer=checkpointer)
config = {"configurable": {"thread_id": "3"}}
res = graph.invoke({"messages": [("human", "what's the weather in sf")]}, config)
checkpoint_tuples = list(checkpointer.list(config))
[CheckpointTuple(config={'configurable': {'thread_id': '3', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-5024-6476-8003-cf0a750e6b37'}}, checkpoint={'v': 1, 'id': '1ef559b7-5024-6476-8003-cf0a750e6b37', 'ts': '2024-08-08T15:32:44.314900+00:00', 'current_tasks': {}, 'pending_sends': [], 'versions_seen': {'agent': {'tools': '00000000000000000000000000000004.022986cd20ae85c77ea298a383f69ba8', 'start:agent': '00000000000000000000000000000002.d6f25946c3108fc12f27abbcf9b4cedc'}, 'tools': {'branch:agent:should_continue:tools': '00000000000000000000000000000003.065d90dd7f7cd091f0233855210bb2af'}, '__input__': {}, '__start__': {'__start__': '00000000000000000000000000000001.ab89befb52cc0e91e106ef7f500ea033'}}, 'channel_versions': {'agent': '00000000000000000000000000000005.065d90dd7f7cd091f0233855210bb2af', 'tools': '00000000000000000000000000000005.', 'messages': '00000000000000000000000000000005.3f8b8d9923575b911e17157008ab75ac', '__start__': '00000000000000000000000000000002.', 'start:agent': '00000000000000000000000000000003.', 'branch:agent:should_continue:tools': '00000000000000000000000000000004.'}, 'channel_values': {'agent': 'agent', 'messages': [HumanMessage(content="what's the weather in sf", id='5bf79d15-6332-4bf5-89bd-ee192b31ed84'), AIMessage(content='', additional_kwargs={'tool_calls': [{'id': 'call_9y3q1BiwW7zGh2gk2faInTRk', 'function': {'arguments': '{"city":"sf"}', 'name': 'get_weather'}, 'type': 'function'}]}, response_metadata={'token_usage': {'completion_tokens': 14, 'prompt_tokens': 57, 'total_tokens': 71}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_507c9469a1', 'finish_reason': 'tool_calls', 'logprobs': None}, id='run-2958adc7-f6a4-415d-ade1-5ee77e0b9276-0', tool_calls=[{'name': 'get_weather', 'args': {'city': 'sf'}, 'id': 'call_9y3q1BiwW7zGh2gk2faInTRk', 'type': 'tool_call'}], usage_metadata={'input_tokens': 57, 'output_tokens': 14, 'total_tokens': 71}), ToolMessage(content="It's always sunny in sf", name='get_weather', id='cac4f90a-dc3e-4bfa-940f-1c630289a583', tool_call_id='call_9y3q1BiwW7zGh2gk2faInTRk'), AIMessage(content='The weather in San Francisco is always sunny!', response_metadata={'token_usage': {'completion_tokens': 10, 'prompt_tokens': 84, 'total_tokens': 94}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_48196bc67a', 'finish_reason': 'stop', 'logprobs': None}, id='run-97d3fb7a-3d2e-4090-84f4-dafdfe44553f-0', usage_metadata={'input_tokens': 84, 'output_tokens': 10, 'total_tokens': 94})]}}, metadata={'step': 3, 'source': 'loop', 'writes': {'agent': {'messages': [AIMessage(content='The weather in San Francisco is always sunny!', response_metadata={'logprobs': None, 'model_name': 'gpt-4o-mini-2024-07-18', 'token_usage': {'total_tokens': 94, 'prompt_tokens': 84, 'completion_tokens': 10}, 'finish_reason': 'stop', 'system_fingerprint': 'fp_48196bc67a'}, id='run-97d3fb7a-3d2e-4090-84f4-dafdfe44553f-0', usage_metadata={'input_tokens': 84, 'output_tokens': 10, 'total_tokens': 94})]}}}, parent_config={'configurable': {'thread_id': '3', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-4b3d-6430-8002-b5c99d2eb4db'}}, pending_writes=None),
CheckpointTuple(config={'configurable': {'thread_id': '3', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-4b3d-6430-8002-b5c99d2eb4db'}}, checkpoint={'v': 1, 'id': '1ef559b7-4b3d-6430-8002-b5c99d2eb4db', 'ts': '2024-08-08T15:32:43.800857+00:00', 'current_tasks': {}, 'pending_sends': [], 'versions_seen': {'agent': {'start:agent': '00000000000000000000000000000002.d6f25946c3108fc12f27abbcf9b4cedc'}, 'tools': {'branch:agent:should_continue:tools': '00000000000000000000000000000003.065d90dd7f7cd091f0233855210bb2af'}, '__input__': {}, '__start__': {'__start__': '00000000000000000000000000000001.ab89befb52cc0e91e106ef7f500ea033'}}, 'channel_versions': {'agent': '00000000000000000000000000000004.', 'tools': '00000000000000000000000000000004.022986cd20ae85c77ea298a383f69ba8', 'messages': '00000000000000000000000000000004.1195f50946feaedb0bae1fdbfadc806b', '__start__': '00000000000000000000000000000002.', 'start:agent': '00000000000000000000000000000003.', 'branch:agent:should_continue:tools': '00000000000000000000000000000004.'}, 'channel_values': {'tools': 'tools', 'messages': [HumanMessage(content="what's the weather in sf", id='5bf79d15-6332-4bf5-89bd-ee192b31ed84'), AIMessage(content='', additional_kwargs={'tool_calls': [{'id': 'call_9y3q1BiwW7zGh2gk2faInTRk', 'function': {'arguments': '{"city":"sf"}', 'name': 'get_weather'}, 'type': 'function'}]}, response_metadata={'token_usage': {'completion_tokens': 14, 'prompt_tokens': 57, 'total_tokens': 71}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_507c9469a1', 'finish_reason': 'tool_calls', 'logprobs': None}, id='run-2958adc7-f6a4-415d-ade1-5ee77e0b9276-0', tool_calls=[{'name': 'get_weather', 'args': {'city': 'sf'}, 'id': 'call_9y3q1BiwW7zGh2gk2faInTRk', 'type': 'tool_call'}], usage_metadata={'input_tokens': 57, 'output_tokens': 14, 'total_tokens': 71}), ToolMessage(content="It's always sunny in sf", name='get_weather', id='cac4f90a-dc3e-4bfa-940f-1c630289a583', tool_call_id='call_9y3q1BiwW7zGh2gk2faInTRk')]}}, metadata={'step': 2, 'source': 'loop', 'writes': {'tools': {'messages': [ToolMessage(content="It's always sunny in sf", name='get_weather', id='cac4f90a-dc3e-4bfa-940f-1c630289a583', tool_call_id='call_9y3q1BiwW7zGh2gk2faInTRk')]}}}, parent_config={'configurable': {'thread_id': '3', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-4b30-6078-8001-eaf8c9bd8844'}}, pending_writes=None),
CheckpointTuple(config={'configurable': {'thread_id': '3', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-4b30-6078-8001-eaf8c9bd8844'}}, checkpoint={'v': 1, 'id': '1ef559b7-4b30-6078-8001-eaf8c9bd8844', 'ts': '2024-08-08T15:32:43.795440+00:00', 'current_tasks': {}, 'pending_sends': [], 'versions_seen': {'agent': {'start:agent': '00000000000000000000000000000002.d6f25946c3108fc12f27abbcf9b4cedc'}, '__input__': {}, '__start__': {'__start__': '00000000000000000000000000000001.ab89befb52cc0e91e106ef7f500ea033'}}, 'channel_versions': {'agent': '00000000000000000000000000000003.065d90dd7f7cd091f0233855210bb2af', 'messages': '00000000000000000000000000000003.bab5fb3a70876f600f5f2fd46945ce5f', '__start__': '00000000000000000000000000000002.', 'start:agent': '00000000000000000000000000000003.', 'branch:agent:should_continue:tools': '00000000000000000000000000000003.065d90dd7f7cd091f0233855210bb2af'}, 'channel_values': {'agent': 'agent', 'messages': [HumanMessage(content="what's the weather in sf", id='5bf79d15-6332-4bf5-89bd-ee192b31ed84'), AIMessage(content='', additional_kwargs={'tool_calls': [{'id': 'call_9y3q1BiwW7zGh2gk2faInTRk', 'function': {'arguments': '{"city":"sf"}', 'name': 'get_weather'}, 'type': 'function'}]}, response_metadata={'token_usage': {'completion_tokens': 14, 'prompt_tokens': 57, 'total_tokens': 71}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_507c9469a1', 'finish_reason': 'tool_calls', 'logprobs': None}, id='run-2958adc7-f6a4-415d-ade1-5ee77e0b9276-0', tool_calls=[{'name': 'get_weather', 'args': {'city': 'sf'}, 'id': 'call_9y3q1BiwW7zGh2gk2faInTRk', 'type': 'tool_call'}], usage_metadata={'input_tokens': 57, 'output_tokens': 14, 'total_tokens': 71})], 'branch:agent:should_continue:tools': 'agent'}}, metadata={'step': 1, 'source': 'loop', 'writes': {'agent': {'messages': [AIMessage(content='', additional_kwargs={'tool_calls': [{'id': 'call_9y3q1BiwW7zGh2gk2faInTRk', 'type': 'function', 'function': {'name': 'get_weather', 'arguments': '{"city":"sf"}'}}]}, response_metadata={'logprobs': None, 'model_name': 'gpt-4o-mini-2024-07-18', 'token_usage': {'total_tokens': 71, 'prompt_tokens': 57, 'completion_tokens': 14}, 'finish_reason': 'tool_calls', 'system_fingerprint': 'fp_507c9469a1'}, id='run-2958adc7-f6a4-415d-ade1-5ee77e0b9276-0', tool_calls=[{'name': 'get_weather', 'args': {'city': 'sf'}, 'id': 'call_9y3q1BiwW7zGh2gk2faInTRk', 'type': 'tool_call'}], usage_metadata={'input_tokens': 57, 'output_tokens': 14, 'total_tokens': 71})]}}}, parent_config={'configurable': {'thread_id': '3', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-46d7-6116-8000-8976b7c89a2f'}}, pending_writes=None),
CheckpointTuple(config={'configurable': {'thread_id': '3', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-46d7-6116-8000-8976b7c89a2f'}}, checkpoint={'v': 1, 'id': '1ef559b7-46d7-6116-8000-8976b7c89a2f', 'ts': '2024-08-08T15:32:43.339573+00:00', 'current_tasks': {}, 'pending_sends': [], 'versions_seen': {'__input__': {}, '__start__': {'__start__': '00000000000000000000000000000001.ab89befb52cc0e91e106ef7f500ea033'}}, 'channel_versions': {'messages': '00000000000000000000000000000002.ba0c90d32863686481f7fe5eab9ecdf0', '__start__': '00000000000000000000000000000002.', 'start:agent': '00000000000000000000000000000002.d6f25946c3108fc12f27abbcf9b4cedc'}, 'channel_values': {'messages': [HumanMessage(content="what's the weather in sf", id='5bf79d15-6332-4bf5-89bd-ee192b31ed84')], 'start:agent': '__start__'}}, metadata={'step': 0, 'source': 'loop', 'writes': None}, parent_config={'configurable': {'thread_id': '3', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-46ce-6c64-bfff-ef7fe2663573'}}, pending_writes=None),
CheckpointTuple(config={'configurable': {'thread_id': '3', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-46ce-6c64-bfff-ef7fe2663573'}}, checkpoint={'v': 1, 'id': '1ef559b7-46ce-6c64-bfff-ef7fe2663573', 'ts': '2024-08-08T15:32:43.336188+00:00', 'current_tasks': {}, 'pending_sends': [], 'versions_seen': {'__input__': {}}, 'channel_versions': {'__start__': '00000000000000000000000000000001.ab89befb52cc0e91e106ef7f500ea033'}, 'channel_values': {'__start__': {'messages': [['human', "what's the weather in sf"]]}}}, metadata={'step': -1, 'source': 'input', 'writes': {'messages': [['human', "what's the weather in sf"]]}}, parent_config=None, pending_writes=None)]
使用异步连接¶
这将设置与数据库的异步连接。
异步连接允许非阻塞的数据库操作。这意味着在等待数据库操作完成时，应用程序的其他部分可以继续运行。这在高并发场景或处理I/O密集型操作时特别有用。
使用连接池¶
from psycopg_pool import AsyncConnectionPool
async with AsyncConnectionPool(
# Example configuration
conninfo=DB_URI,
max_size=20,
kwargs=connection_kwargs,
) as pool:
checkpointer = AsyncPostgresSaver(pool)
# NOTE: you need to call .setup() the first time you're using your checkpointer
await checkpointer.setup()
graph = create_react_agent(model, tools=tools, checkpointer=checkpointer)
config = {"configurable": {"thread_id": "4"}}
res = await graph.ainvoke(
{"messages": [("human", "what's the weather in nyc")]}, config
)
checkpoint = await checkpointer.aget(config)
{'v': 1,
'id': '1ef559b7-5cc9-6460-8003-8655824c0944',
'ts': '2024-08-08T15:32:45.640793+00:00',
'current_tasks': {},
'pending_sends': [],
'versions_seen': {'agent': {'tools': '00000000000000000000000000000004.022986cd20ae85c77ea298a383f69ba8',
'start:agent': '00000000000000000000000000000002.d6f25946c3108fc12f27abbcf9b4cedc'},
'tools': {'branch:agent:should_continue:tools': '00000000000000000000000000000003.065d90dd7f7cd091f0233855210bb2af'},
'__input__': {},
'__start__': {'__start__': '00000000000000000000000000000001.0e148ae3debe753278387e84f786e863'}},
'channel_versions': {'agent': '00000000000000000000000000000005.065d90dd7f7cd091f0233855210bb2af',
'tools': '00000000000000000000000000000005.',
'messages': '00000000000000000000000000000005.d869fc7231619df0db74feed624efe41',
'__start__': '00000000000000000000000000000002.',
'start:agent': '00000000000000000000000000000003.',
'branch:agent:should_continue:tools': '00000000000000000000000000000004.'},
'channel_values': {'agent': 'agent',
'messages': [HumanMessage(content="what's the weather in nyc", id='d883b8a0-99de-486d-91a2-bcfa7f25dc05'),
AIMessage(content='', additional_kwargs={'tool_calls': [{'id': 'call_H6TAYfyd6AnaCrkQGs6Q2fVp', 'function': {'arguments': '{"city":"nyc"}', 'name': 'get_weather'}, 'type': 'function'}]}, response_metadata={'token_usage': {'completion_tokens': 15, 'prompt_tokens': 58, 'total_tokens': 73}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_48196bc67a', 'finish_reason': 'tool_calls', 'logprobs': None}, id='run-6f542f84-ad73-444c-8ef7-b5ea75a2e09b-0', tool_calls=[{'name': 'get_weather', 'args': {'city': 'nyc'}, 'id': 'call_H6TAYfyd6AnaCrkQGs6Q2fVp', 'type': 'tool_call'}], usage_metadata={'input_tokens': 58, 'output_tokens': 15, 'total_tokens': 73}),
ToolMessage(content='It might be cloudy in nyc', name='get_weather', id='c0e52254-77a4-4ea9-a2b7-61dd2d65ec68', tool_call_id='call_H6TAYfyd6AnaCrkQGs6Q2fVp'),
AIMessage(content='The weather in NYC might be cloudy.', response_metadata={'token_usage': {'completion_tokens': 9, 'prompt_tokens': 88, 'total_tokens': 97}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_48196bc67a', 'finish_reason': 'stop', 'logprobs': None}, id='run-977140d4-7582-40c3-b2b6-31b542c430a3-0', usage_metadata={'input_tokens': 88, 'output_tokens': 9, 'total_tokens': 97})]}}
建立连接后¶
from psycopg import AsyncConnection
async with await AsyncConnection.connect(DB_URI, **connection_kwargs) as conn:
checkpointer = AsyncPostgresSaver(conn)
graph = create_react_agent(model, tools=tools, checkpointer=checkpointer)
config = {"configurable": {"thread_id": "5"}}
res = await graph.ainvoke(
{"messages": [("human", "what's the weather in nyc")]}, config
)
checkpoint_tuple = await checkpointer.aget_tuple(config)
CheckpointTuple(config={'configurable': {'thread_id': '5', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-65b4-60ca-8003-1ef4b620559a'}}, checkpoint={'v': 1, 'id': '1ef559b7-65b4-60ca-8003-1ef4b620559a', 'ts': '2024-08-08T15:32:46.575814+00:00', 'current_tasks': {}, 'pending_sends': [], 'versions_seen': {'agent': {'tools': '00000000000000000000000000000004.022986cd20ae85c77ea298a383f69ba8', 'start:agent': '00000000000000000000000000000002.d6f25946c3108fc12f27abbcf9b4cedc'}, 'tools': {'branch:agent:should_continue:tools': '00000000000000000000000000000003.065d90dd7f7cd091f0233855210bb2af'}, '__input__': {}, '__start__': {'__start__': '00000000000000000000000000000001.0e148ae3debe753278387e84f786e863'}}, 'channel_versions': {'agent': '00000000000000000000000000000005.065d90dd7f7cd091f0233855210bb2af', 'tools': '00000000000000000000000000000005.', 'messages': '00000000000000000000000000000005.1557a6006d58f736d5cb2dd5c5f10111', '__start__': '00000000000000000000000000000002.', 'start:agent': '00000000000000000000000000000003.', 'branch:agent:should_continue:tools': '00000000000000000000000000000004.'}, 'channel_values': {'agent': 'agent', 'messages': [HumanMessage(content="what's the weather in nyc", id='935e7732-b288-49bd-9ec2-1f7610cc38cb'), AIMessage(content='', additional_kwargs={'tool_calls': [{'id': 'call_94KtjtPmsiaj7T8yXvL7Ef31', 'function': {'arguments': '{"city":"nyc"}', 'name': 'get_weather'}, 'type': 'function'}]}, response_metadata={'token_usage': {'completion_tokens': 15, 'prompt_tokens': 58, 'total_tokens': 73}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_48196bc67a', 'finish_reason': 'tool_calls', 'logprobs': None}, id='run-790c929a-7982-49e7-af67-2cbe4a86373b-0', tool_calls=[{'name': 'get_weather', 'args': {'city': 'nyc'}, 'id': 'call_94KtjtPmsiaj7T8yXvL7Ef31', 'type': 'tool_call'}], usage_metadata={'input_tokens': 58, 'output_tokens': 15, 'total_tokens': 73}), ToolMessage(content='It might be cloudy in nyc', name='get_weather', id='b2dc1073-abc4-4492-8982-434a7e32e445', tool_call_id='call_94KtjtPmsiaj7T8yXvL7Ef31'), AIMessage(content='The weather in NYC might be cloudy.', response_metadata={'token_usage': {'completion_tokens': 9, 'prompt_tokens': 88, 'total_tokens': 97}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_48196bc67a', 'finish_reason': 'stop', 'logprobs': None}, id='run-7e8a7f16-d8e1-457a-89f3-192102396449-0', usage_metadata={'input_tokens': 88, 'output_tokens': 9, 'total_tokens': 97})]}}, metadata={'step': 3, 'source': 'loop', 'writes': {'agent': {'messages': [AIMessage(content='The weather in NYC might be cloudy.', response_metadata={'logprobs': None, 'model_name': 'gpt-4o-mini-2024-07-18', 'token_usage': {'total_tokens': 97, 'prompt_tokens': 88, 'completion_tokens': 9}, 'finish_reason': 'stop', 'system_fingerprint': 'fp_48196bc67a'}, id='run-7e8a7f16-d8e1-457a-89f3-192102396449-0', usage_metadata={'input_tokens': 88, 'output_tokens': 9, 'total_tokens': 97})]}}}, parent_config={'configurable': {'thread_id': '5', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-62ae-6128-8002-c04af82bcd41'}}, pending_writes=[])
使用连接字符串¶
async with AsyncPostgresSaver.from_conn_string(DB_URI) as checkpointer:
graph = create_react_agent(model, tools=tools, checkpointer=checkpointer)
config = {"configurable": {"thread_id": "6"}}
res = await graph.ainvoke(
{"messages": [("human", "what's the weather in nyc")]}, config
)
checkpoint_tuples = [c async for c in checkpointer.alist(config)]
[CheckpointTuple(config={'configurable': {'thread_id': '6', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-723c-67de-8003-63bd4eab35af'}}, checkpoint={'v': 1, 'id': '1ef559b7-723c-67de-8003-63bd4eab35af', 'ts': '2024-08-08T15:32:47.890003+00:00', 'current_tasks': {}, 'pending_sends': [], 'versions_seen': {'agent': {'tools': '00000000000000000000000000000004.022986cd20ae85c77ea298a383f69ba8', 'start:agent': '00000000000000000000000000000002.d6f25946c3108fc12f27abbcf9b4cedc'}, 'tools': {'branch:agent:should_continue:tools': '00000000000000000000000000000003.065d90dd7f7cd091f0233855210bb2af'}, '__input__': {}, '__start__': {'__start__': '00000000000000000000000000000001.0e148ae3debe753278387e84f786e863'}}, 'channel_versions': {'agent': '00000000000000000000000000000005.065d90dd7f7cd091f0233855210bb2af', 'tools': '00000000000000000000000000000005.', 'messages': '00000000000000000000000000000005.b6fe2a26011590cfe8fd6a39151a9e92', '__start__': '00000000000000000000000000000002.', 'start:agent': '00000000000000000000000000000003.', 'branch:agent:should_continue:tools': '00000000000000000000000000000004.'}, 'channel_values': {'agent': 'agent', 'messages': [HumanMessage(content="what's the weather in nyc", id='977ddb90-9991-44cb-9f73-361c6dd21396'), AIMessage(content='', additional_kwargs={'tool_calls': [{'id': 'call_QIFCuh4zfP9owpjToycJiZf7', 'function': {'arguments': '{"city":"nyc"}', 'name': 'get_weather'}, 'type': 'function'}]}, response_metadata={'token_usage': {'completion_tokens': 15, 'prompt_tokens': 58, 'total_tokens': 73}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_48196bc67a', 'finish_reason': 'tool_calls', 'logprobs': None}, id='run-47b10c48-4db3-46d8-b4fa-e021818e01c5-0', tool_calls=[{'name': 'get_weather', 'args': {'city': 'nyc'}, 'id': 'call_QIFCuh4zfP9owpjToycJiZf7', 'type': 'tool_call'}], usage_metadata={'input_tokens': 58, 'output_tokens': 15, 'total_tokens': 73}), ToolMessage(content='It might be cloudy in nyc', name='get_weather', id='798c520f-4f9a-4f6d-a389-da721eb4d4ce', tool_call_id='call_QIFCuh4zfP9owpjToycJiZf7'), AIMessage(content='The weather in NYC might be cloudy.', response_metadata={'token_usage': {'completion_tokens': 9, 'prompt_tokens': 88, 'total_tokens': 97}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_48196bc67a', 'finish_reason': 'stop', 'logprobs': None}, id='run-4a34e05d-8bcf-41ad-adc3-715919fde64c-0', usage_metadata={'input_tokens': 88, 'output_tokens': 9, 'total_tokens': 97})]}}, metadata={'step': 3, 'source': 'loop', 'writes': {'agent': {'messages': [AIMessage(content='The weather in NYC might be cloudy.', response_metadata={'logprobs': None, 'model_name': 'gpt-4o-mini-2024-07-18', 'token_usage': {'total_tokens': 97, 'prompt_tokens': 88, 'completion_tokens': 9}, 'finish_reason': 'stop', 'system_fingerprint': 'fp_48196bc67a'}, id='run-4a34e05d-8bcf-41ad-adc3-715919fde64c-0', usage_metadata={'input_tokens': 88, 'output_tokens': 9, 'total_tokens': 97})]}}}, parent_config={'configurable': {'thread_id': '6', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-6bf5-63c6-8002-ed990dbbc96e'}}, pending_writes=None),
CheckpointTuple(config={'configurable': {'thread_id': '6', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-6bf5-63c6-8002-ed990dbbc96e'}}, checkpoint={'v': 1, 'id': '1ef559b7-6bf5-63c6-8002-ed990dbbc96e', 'ts': '2024-08-08T15:32:47.231667+00:00', 'current_tasks': {}, 'pending_sends': [], 'versions_seen': {'agent': {'start:agent': '00000000000000000000000000000002.d6f25946c3108fc12f27abbcf9b4cedc'}, 'tools': {'branch:agent:should_continue:tools': '00000000000000000000000000000003.065d90dd7f7cd091f0233855210bb2af'}, '__input__': {}, '__start__': {'__start__': '00000000000000000000000000000001.0e148ae3debe753278387e84f786e863'}}, 'channel_versions': {'agent': '00000000000000000000000000000004.', 'tools': '00000000000000000000000000000004.022986cd20ae85c77ea298a383f69ba8', 'messages': '00000000000000000000000000000004.c9074f2a41f05486b5efb86353dc75c0', '__start__': '00000000000000000000000000000002.', 'start:agent': '00000000000000000000000000000003.', 'branch:agent:should_continue:tools': '00000000000000000000000000000004.'}, 'channel_values': {'tools': 'tools', 'messages': [HumanMessage(content="what's the weather in nyc", id='977ddb90-9991-44cb-9f73-361c6dd21396'), AIMessage(content='', additional_kwargs={'tool_calls': [{'id': 'call_QIFCuh4zfP9owpjToycJiZf7', 'function': {'arguments': '{"city":"nyc"}', 'name': 'get_weather'}, 'type': 'function'}]}, response_metadata={'token_usage': {'completion_tokens': 15, 'prompt_tokens': 58, 'total_tokens': 73}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_48196bc67a', 'finish_reason': 'tool_calls', 'logprobs': None}, id='run-47b10c48-4db3-46d8-b4fa-e021818e01c5-0', tool_calls=[{'name': 'get_weather', 'args': {'city': 'nyc'}, 'id': 'call_QIFCuh4zfP9owpjToycJiZf7', 'type': 'tool_call'}], usage_metadata={'input_tokens': 58, 'output_tokens': 15, 'total_tokens': 73}), ToolMessage(content='It might be cloudy in nyc', name='get_weather', id='798c520f-4f9a-4f6d-a389-da721eb4d4ce', tool_call_id='call_QIFCuh4zfP9owpjToycJiZf7')]}}, metadata={'step': 2, 'source': 'loop', 'writes': {'tools': {'messages': [ToolMessage(content='It might be cloudy in nyc', name='get_weather', id='798c520f-4f9a-4f6d-a389-da721eb4d4ce', tool_call_id='call_QIFCuh4zfP9owpjToycJiZf7')]}}}, parent_config={'configurable': {'thread_id': '6', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-6be0-6926-8001-1a8ce73baf9e'}}, pending_writes=None),
CheckpointTuple(config={'configurable': {'thread_id': '6', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-6be0-6926-8001-1a8ce73baf9e'}}, checkpoint={'v': 1, 'id': '1ef559b7-6be0-6926-8001-1a8ce73baf9e', 'ts': '2024-08-08T15:32:47.223198+00:00', 'current_tasks': {}, 'pending_sends': [], 'versions_seen': {'agent': {'start:agent': '00000000000000000000000000000002.d6f25946c3108fc12f27abbcf9b4cedc'}, '__input__': {}, '__start__': {'__start__': '00000000000000000000000000000001.0e148ae3debe753278387e84f786e863'}}, 'channel_versions': {'agent': '00000000000000000000000000000003.065d90dd7f7cd091f0233855210bb2af', 'messages': '00000000000000000000000000000003.097b5407d709b297591f1ef5d50c8368', '__start__': '00000000000000000000000000000002.', 'start:agent': '00000000000000000000000000000003.', 'branch:agent:should_continue:tools': '00000000000000000000000000000003.065d90dd7f7cd091f0233855210bb2af'}, 'channel_values': {'agent': 'agent', 'messages': [HumanMessage(content="what's the weather in nyc", id='977ddb90-9991-44cb-9f73-361c6dd21396'), AIMessage(content='', additional_kwargs={'tool_calls': [{'id': 'call_QIFCuh4zfP9owpjToycJiZf7', 'function': {'arguments': '{"city":"nyc"}', 'name': 'get_weather'}, 'type': 'function'}]}, response_metadata={'token_usage': {'completion_tokens': 15, 'prompt_tokens': 58, 'total_tokens': 73}, 'model_name': 'gpt-4o-mini-2024-07-18', 'system_fingerprint': 'fp_48196bc67a', 'finish_reason': 'tool_calls', 'logprobs': None}, id='run-47b10c48-4db3-46d8-b4fa-e021818e01c5-0', tool_calls=[{'name': 'get_weather', 'args': {'city': 'nyc'}, 'id': 'call_QIFCuh4zfP9owpjToycJiZf7', 'type': 'tool_call'}], usage_metadata={'input_tokens': 58, 'output_tokens': 15, 'total_tokens': 73})], 'branch:agent:should_continue:tools': 'agent'}}, metadata={'step': 1, 'source': 'loop', 'writes': {'agent': {'messages': [AIMessage(content='', additional_kwargs={'tool_calls': [{'id': 'call_QIFCuh4zfP9owpjToycJiZf7', 'type': 'function', 'function': {'name': 'get_weather', 'arguments': '{"city":"nyc"}'}}]}, response_metadata={'logprobs': None, 'model_name': 'gpt-4o-mini-2024-07-18', 'token_usage': {'total_tokens': 73, 'prompt_tokens': 58, 'completion_tokens': 15}, 'finish_reason': 'tool_calls', 'system_fingerprint': 'fp_48196bc67a'}, id='run-47b10c48-4db3-46d8-b4fa-e021818e01c5-0', tool_calls=[{'name': 'get_weather', 'args': {'city': 'nyc'}, 'id': 'call_QIFCuh4zfP9owpjToycJiZf7', 'type': 'tool_call'}], usage_metadata={'input_tokens': 58, 'output_tokens': 15, 'total_tokens': 73})]}}}, parent_config={'configurable': {'thread_id': '6', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-663d-60b4-8000-10a8922bffbf'}}, pending_writes=None),
CheckpointTuple(config={'configurable': {'thread_id': '6', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-663d-60b4-8000-10a8922bffbf'}}, checkpoint={'v': 1, 'id': '1ef559b7-663d-60b4-8000-10a8922bffbf', 'ts': '2024-08-08T15:32:46.631935+00:00', 'current_tasks': {}, 'pending_sends': [], 'versions_seen': {'__input__': {}, '__start__': {'__start__': '00000000000000000000000000000001.0e148ae3debe753278387e84f786e863'}}, 'channel_versions': {'messages': '00000000000000000000000000000002.2a79db8da664e437bdb25ea804457ca7', '__start__': '00000000000000000000000000000002.', 'start:agent': '00000000000000000000000000000002.d6f25946c3108fc12f27abbcf9b4cedc'}, 'channel_values': {'messages': [HumanMessage(content="what's the weather in nyc", id='977ddb90-9991-44cb-9f73-361c6dd21396')], 'start:agent': '__start__'}}, metadata={'step': 0, 'source': 'loop', 'writes': None}, parent_config={'configurable': {'thread_id': '6', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-6637-6d4e-bfff-6cecf690c3cb'}}, pending_writes=None),
CheckpointTuple(config={'configurable': {'thread_id': '6', 'checkpoint_ns': '', 'checkpoint_id': '1ef559b7-6637-6d4e-bfff-6cecf690c3cb'}}, checkpoint={'v': 1, 'id': '1ef559b7-6637-6d4e-bfff-6cecf690c3cb', 'ts': '2024-08-08T15:32:46.629806+00:00', 'current_tasks': {}, 'pending_sends': [], 'versions_seen': {'__input__': {}}, 'channel_versions': {'__start__': '00000000000000000000000000000001.0e148ae3debe753278387e84f786e863'}, 'channel_values': {'__start__': {'messages': [['human', "what's the weather in nyc"]]}}}, metadata={'step': -1, 'source': 'input', 'writes': {'messages': [['human', "what's the weather in nyc"]]}}, parent_config=None, pending_writes=None)]