langgraph-checkpoint-mysql

LangGraph Checkpoint MySQL

Implementation of LangGraph CheckpointSaver that uses MySQL.

[!TIP] The code in this repository tries to mimic the code in langgraph-checkpoint-postgres as much as possible to enable keeping in sync with the official checkpointer implementation.

[!NOTE] In order to keep the queries close to the Postgres queries, we use features from recent versions of MySQL 8. I'm not sure what the exact minimum version is.

Dependencies

To use synchronous PyMySQLSaver, install langgraph-checkpoint-mysql[pymysql]. To use asynchronous AIOMySQLSaver, install langgraph-checkpoint-mysql[aiomysql].

There is currently no support for other drivers.

Usage

[!IMPORTANT] When using MySQL checkpointers for the first time, make sure to call .setup() method on them to create required tables. See example below.

[!IMPORTANT] When manually creating MySQL connections and passing them to PyMySQLSaver or AIOMySQLSaver, make sure to include autocommit=True.

from langgraph.checkpoint.mysql.pymysql import PyMySQLSaver

write_config = {"configurable": {"thread_id": "1", "checkpoint_ns": ""}}
read_config = {"configurable": {"thread_id": "1"}}

DB_URI = "mysql://mysql:mysql@localhost:3306/mysql"
with PyMySQLSaver.from_conn_string(DB_URI) as checkpointer:
    # call .setup() the first time you're using the checkpointer
    checkpointer.setup()
    checkpoint = {
        "v": 1,
        "ts": "2024-07-31T20:14:19.804150+00:00",
        "id": "1ef4f797-8335-6428-8001-8a1503f9b875",
        "channel_values": {
            "my_key": "meow",
            "node": "node"
        },
        "channel_versions": {
            "__start__": 2,
            "my_key": 3,
            "start:node": 3,
            "node": 3
        },
        "versions_seen": {
            "__input__": {},
            "__start__": {
            "__start__": 1
            },
            "node": {
            "start:node": 2
            }
        },
        "pending_sends": [],
    }

    # store checkpoint
    checkpointer.put(write_config, checkpoint, {}, {})

    # load checkpoint
    checkpointer.get(read_config)

    # list checkpoints
    list(checkpointer.list(read_config))

Async

from langgraph.checkpoint.mysql.aio import AIOMySQLSaver

async with AIOMySQLSaver.from_conn_string(DB_URI) as checkpointer:
    checkpoint = {
        "v": 1,
        "ts": "2024-07-31T20:14:19.804150+00:00",
        "id": "1ef4f797-8335-6428-8001-8a1503f9b875",
        "channel_values": {
            "my_key": "meow",
            "node": "node"
        },
        "channel_versions": {
            "__start__": 2,
            "my_key": 3,
            "start:node": 3,
            "node": 3
        },
        "versions_seen": {
            "__input__": {},
            "__start__": {
            "__start__": 1
            },
            "node": {
            "start:node": 2
            }
        },
        "pending_sends": [],
    }

    # store checkpoint
    await checkpointer.aput(write_config, checkpoint, {}, {})

    # load checkpoint
    await checkpointer.aget(read_config)

    # list checkpoints
    [c async for c in checkpointer.alist(read_config)]