mirror of
https://github.com/langchain-ai/langgraph.git
synced 2026-08-17 21:25:46 +02:00
Nuno Campos
d22fe60d4c
- any invalid utf-8 chars now removed on dumps - fix serialization of Send - remove serialization of NamedTuple, which doesn't work - add test for custom serde passed to memory saver - add test using Send and JsonPlus serde
115 lines
3.5 KiB
Python
115 lines
3.5 KiB
Python
import asyncio
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from collections import defaultdict
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from typing import Any, Optional
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from langchain_core.runnables import RunnableConfig
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from langgraph.checkpoint.base import (
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Checkpoint,
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CheckpointMetadata,
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SerializerProtocol,
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copy_checkpoint,
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)
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from langgraph.checkpoint.memory import MemorySaver
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class NoopSerializer(SerializerProtocol):
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def loads(self, data: bytes) -> Any:
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return data
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def dumps(self, obj: Any) -> bytes:
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return obj
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class MemorySaverAssertImmutable(MemorySaver):
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serde = NoopSerializer()
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storage_for_copies: defaultdict[str, dict[str, Checkpoint]]
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def __init__(
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self,
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*,
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serde: Optional[SerializerProtocol] = None,
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) -> None:
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super().__init__(serde=serde)
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self.storage_for_copies = defaultdict(dict)
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def put(
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self,
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config: dict,
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checkpoint: Checkpoint,
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metadata: Optional[CheckpointMetadata] = None,
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) -> None:
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# assert checkpoint hasn't been modified since last written
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thread_id = config["configurable"]["thread_id"]
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if saved := super().get(config):
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assert (
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self.serde.loads(self.storage_for_copies[thread_id][saved["id"]])
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== saved
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)
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self.storage_for_copies[thread_id][checkpoint["id"]] = self.serde.dumps(
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copy_checkpoint(checkpoint)
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)
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# call super to write checkpoint
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return super().put(config, checkpoint, metadata)
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class MemorySaverAssertCheckpointMetadata(MemorySaver):
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"""This custom checkpointer is for verifying that a run's configurable
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fields are merged with the previous checkpoint config for each step in
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the run. This is the desired behavior. Because the checkpointer's (a)put()
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method is called for each step, the implementation of this checkpointer
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should produce a side effect that can be asserted.
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"""
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serde = NoopSerializer()
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def __init__(
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self,
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*,
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serde: Optional[SerializerProtocol] = None,
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) -> None:
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super().__init__(serde=serde)
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def put(
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self,
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config: RunnableConfig,
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checkpoint: Checkpoint,
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metadata: Optional[CheckpointMetadata] = None,
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) -> None:
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"""The implementation of put() merges config["configurable"] (a run's
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configurable fields) with the metadata field. The state of the
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checkpoint metadata can be asserted to confirm that the run's
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configurable fields were merged with the previous checkpoint config.
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"""
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configurable = config["configurable"].copy()
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# remove thread_ts to make testing simpler
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configurable.pop("thread_ts", None)
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self.storage[config["configurable"]["thread_id"]].update(
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{
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checkpoint["id"]: (
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self.serde.dumps(checkpoint),
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# merge configurable fields and metadata
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self.serde.dumps({**configurable, **metadata}),
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)
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}
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)
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return {
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"configurable": {
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"thread_id": config["configurable"]["thread_id"],
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"thread_ts": checkpoint["id"],
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}
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}
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async def aput(
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self,
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config: RunnableConfig,
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checkpoint: Checkpoint,
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metadata: CheckpointMetadata,
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) -> RunnableConfig:
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return await asyncio.get_running_loop().run_in_executor(
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None, self.put, config, checkpoint, metadata
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)
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