LangGraph Worker Python gRPC Server

This directory contains a Python implementation of the gRPC server defined in server.proto. The server implements the Worker service which provides methods for streaming nodes and invoking reducers.

Setup

Install the required dependencies:

pip install -r requirements.txt

Compile the Protocol Buffer definition to generate Python code:

python compile_proto.py

This will generate the necessary Python modules in the stubs directory.

Server Implementation

The server implementation is in grpc_server.py. It provides:

A WorkerServicer class that implements the Worker service defined in the proto file
Methods to register handlers for nodes and reducers
Helper methods to create write and error events

Running the Server

To run the server:

python grpc_server.py [port]

By default, the server listens on port 50051.

Customizing the Server

To customize the server behavior, modify the register_handlers function in grpc_server.py to register your own node and reducer handlers.

Example:

def register_handlers(servicer: WorkerServicer):
    # Custom node handler
    def my_node_handler(inputs, config, path):
        # Process inputs and return results
        return {"output": b"Processed result"}
    
    # Register the handler
    servicer.register_node_handler("my_node", my_node_handler)

Protocol Buffer Definition

The Protocol Buffer definition in server.proto defines:

Config: Configuration for checkpoints
PregelExecutableTask: Task information for execution
Event: Output events (write or error)
Worker service: Service with methods for streaming nodes and invoking reducers