LangGraph Redis

This repository contains Redis implementations for LangGraph, providing both Checkpoint Savers and Stores functionality.

Overview

The project consists of two main components:

1. Redis Checkpoint Savers: Implementations for storing and managing checkpoints using Redis
2. Redis Stores: Redis-backed key-value stores with optional vector search capabilities

Dependencies

The project requires the following main dependencies:

• redis>=5.2.1
• redisvl>=0.5.1
• langgraph-checkpoint>=2.0.24

Installation

Install the library using pip:

pip install langgraph-checkpoint-redis

Redis Checkpoint Savers

Important Notes

Important

When using Redis checkpointers for the first time, make sure to call .setup() method on them to create required indices. See examples below.

Standard Implementation

from langgraph.checkpoint.redis import RedisSaver

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

with RedisSaver.from_conn_string("redis://localhost:6379") as checkpointer:
    # Call setup to initialize indices
    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, {}, {})

    # Retrieve checkpoint
    loaded_checkpoint = checkpointer.get(read_config)

    # List all checkpoints
    checkpoints = list(checkpointer.list(read_config))

Async Implementation

from langgraph.checkpoint.redis.aio import AsyncRedisSaver

async def main():
    write_config = {"configurable": {"thread_id": "1", "checkpoint_ns": ""}}
    read_config = {"configurable": {"thread_id": "1"}}

    async with AsyncRedisSaver.from_conn_string("redis://localhost:6379") as checkpointer:
        # Call setup to initialize indices
        await checkpointer.asetup()
        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, {}, {})

        # Retrieve checkpoint
        loaded_checkpoint = await checkpointer.aget(read_config)

        # List all checkpoints
        checkpoints = [c async for c in checkpointer.alist(read_config)]

# Run the async main function
import asyncio
asyncio.run(main())

Shallow Implementations

Shallow Redis checkpoint savers store only the latest checkpoint in Redis. These implementations are useful when retaining a complete checkpoint history is unnecessary.

from langgraph.checkpoint.redis.shallow import ShallowRedisSaver
# For async version: from langgraph.checkpoint.redis.ashallow import AsyncShallowRedisSaver

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

with ShallowRedisSaver.from_conn_string("redis://localhost:6379") as checkpointer:
    checkpointer.setup()
    # ... rest of the implementation follows similar pattern

Redis Checkpoint TTL Support

Both Redis checkpoint savers and stores support Time-To-Live (TTL) functionality for automatic key expiration:

# Configure TTL for checkpoint savers
ttl_config = {
    "default_ttl": 60,     # Default TTL in minutes
    "refresh_on_read": True,  # Refresh TTL when checkpoint is read
}

# Use with any checkpoint saver implementation
with RedisSaver.from_conn_string("redis://localhost:6379", ttl=ttl_config) as checkpointer:
    checkpointer.setup()
    # Use the checkpointer...

This makes it easy to manage storage and ensure ephemeral data is automatically cleaned up.

Redis Stores

Redis Stores provide a persistent key-value store with optional vector search capabilities.

Synchronous Implementation

from langgraph.store.redis import RedisStore

# Basic usage
with RedisStore.from_conn_string("redis://localhost:6379") as store:
    store.setup()
    # Use the store...

# With vector search configuration
index_config = {
    "dims": 1536,  # Vector dimensions
    "distance_type": "cosine",  # Distance metric
    "fields": ["text"],  # Fields to index
}

# With TTL configuration
ttl_config = {
    "default_ttl": 60,     # Default TTL in minutes
    "refresh_on_read": True,  # Refresh TTL when store entries are read
}

with RedisStore.from_conn_string(
    "redis://localhost:6379", 
    index=index_config,
    ttl=ttl_config
) as store:
    store.setup()
    # Use the store with vector search and TTL capabilities...

Async Implementation

from langgraph.store.redis.aio import AsyncRedisStore

async def main():
    # TTL also works with async implementations
    ttl_config = {
        "default_ttl": 60,     # Default TTL in minutes
        "refresh_on_read": True,  # Refresh TTL when store entries are read
    }
    
    async with AsyncRedisStore.from_conn_string(
        "redis://localhost:6379", 
        ttl=ttl_config
    ) as store:
        await store.setup()
        # Use the store asynchronously...

asyncio.run(main())

Examples

The examples directory contains Jupyter notebooks demonstrating the usage of Redis with LangGraph:

• persistence_redis.ipynb: Demonstrates the usage of Redis checkpoint savers with LangGraph
• create-react-agent-memory.ipynb: Shows how to create an agent with persistent memory using Redis
• cross-thread-persistence.ipynb: Demonstrates cross-thread persistence capabilities
• persistence-functional.ipynb: Shows functional persistence patterns with Redis

Running Example Notebooks

To run the example notebooks with Docker:

1. Navigate to the examples directory:

   cd examples

2. Start the Docker containers:

   docker compose up

3. Open the URL shown in the console (typically http://127.0.0.1:8888/tree) in your browser to access Jupyter.

4. When finished, stop the containers:

   docker compose down

Implementation Details

Indexing

The Redis implementation creates these main indices:

1. Checkpoints Index: Stores checkpoint metadata and versioning
2. Channel Values Index: Stores channel-specific data
3. Writes Index: Tracks pending writes and intermediate states

For Redis Stores with vector search:

1. Store Index: Main key-value store
2. Vector Index: Optional vector embeddings for similarity search

TTL Implementation

Both Redis checkpoint savers and stores leverage Redis's native key expiration:

• Native Redis TTL: Uses Redis's built-in EXPIRE command
• Automatic Cleanup: Redis automatically removes expired keys
• Configurable Default TTL: Set a default TTL for all keys in minutes
• TTL Refresh on Read: Optionally refresh TTL when keys are accessed
• Applied to All Related Keys: TTL is applied to all related keys (checkpoint, blobs, writes)

Contributing

We welcome contributions! Here's how you can help:

Development Setup

1. Clone the repository:

   git clone https://github.com/redis-developer/langgraph-redis
   cd langgraph-redis

2. Install dependencies:

   poetry install --all-extras

Available Commands

The project includes several make commands for development:

• Testing:

  make test           # Run all tests
  make test-all       # Run all tests including API tests

• Linting and Formatting:

  make format        # Format all files with Black and isort
  make lint          # Run formatting, type checking, and other linters
  make check-types   # Run mypy type checking

• Redis for Development/Testing:

  make redis-start   # Start Redis in Docker
  make redis-stop    # Stop Redis container

Contribution Guidelines

1. Create a new branch for your changes
2. Write tests for new functionality
3. Ensure all tests pass: make test
4. Format your code: make format
5. Run linting checks: make lint
6. Submit a pull request with a clear description of your changes
7. Follow Conventional Commits for commit messages

License

This project is licensed under the MIT License.