Crate weavegraph 

Weavegraph: Graph-driven Agent Workflow Framework

Weavegraph is a framework for building concurrent, stateful workflows using graph-based execution with versioned state management and deterministic barrier merges.

Core Concepts

• Nodes: Async units of work that process state snapshots
• Messages: Communication primitives with role-based typing
• State: Versioned, channel-based state management
• Graph: Declarative workflow definition with conditional edges
• Scheduler: Concurrent execution with dependency tracking

Quick Start

Working with Messages

Messages are the primary communication primitive. Use convenience constructors:

use weavegraph::message::Message;

// Preferred: Use convenience constructors
let user_msg = Message::user("What's the weather like?");
let assistant_msg = Message::assistant("It's sunny and 75°F!");
let system_msg = Message::system("You are a helpful assistant.");

// For custom roles, use the general constructor
let function_msg = Message::new("function", "Processing complete");

// Use role constants for consistency
let user_msg2 = Message::new(Message::USER, "Another user message");

// Check message roles
assert!(user_msg.has_role(Message::USER));
assert!(!user_msg.has_role(Message::ASSISTANT));

Building a Simple Workflow

use weavegraph::{
    graphs::GraphBuilder,
    node::{Node, NodeContext, NodePartial},
    message::Message,
    state::VersionedState,
    types::NodeKind,
};
use async_trait::async_trait;

// Define a simple node
struct GreetingNode;

#[async_trait]
impl Node for GreetingNode {
    async fn run(
        &self,
        snapshot: weavegraph::state::StateSnapshot,
        _ctx: NodeContext,
    ) -> Result<NodePartial, weavegraph::node::NodeError> {
        // Use convenience constructor instead of verbose struct syntax
        let greeting = Message::assistant("Hello! How can I help you today?");
         
        Ok(NodePartial {
            messages: Some(vec![greeting]),
            extra: None,
            errors: None,
        })
    }
}

State Management

use weavegraph::state::VersionedState;
use weavegraph::message::Message;

// Create initial state with user message
let state = VersionedState::new_with_user_message("Hello, system!");

// Or use the builder pattern for complex initialization
let complex_state = VersionedState::builder()
    .with_user_message("What's the weather?")
    .with_system_message("You are a weather assistant")
    .with_extra("location", serde_json::json!("San Francisco"))
    .build();

Best Practices

Message Construction

use weavegraph::message::Message;

// ✅ GOOD: Use convenience constructors
let user_msg = Message::user("Hello");
let assistant_msg = Message::assistant("Hi there!");
let system_msg = Message::system("You are helpful");

// ✅ GOOD: Use role constants for consistency
let custom_msg = Message::new(Message::USER, "Custom content");

// ✅ GOOD: Use general constructor for custom roles
let function_msg = Message::new("function", "Result: success");

// ❌ AVOID: Direct struct construction (verbose and error-prone)
// let verbose_msg = Message {
//     role: "user".to_string(),
//     content: "Hello".to_string(),
// };

Error Handling

The framework uses comprehensive error types with detailed context:

use weavegraph::node::{NodeError, NodeContext};

// Errors are automatically traced and can be emitted to the event bus
fn example_error_handling(ctx: &NodeContext) -> Result<(), NodeError> {
    ctx.emit("validation", "Checking input parameters")?;
     
    // Framework provides rich error types
    Err(NodeError::MissingInput {
        what: "user_id",
    })
}

Module Guide

• message - Message types and construction utilities
• state - Versioned state management and snapshots
• node - Node trait and execution primitives
• graphs - Workflow graph definition and compilation
• schedulers - Concurrent execution and dependency resolution
• runtimes - High-level execution runtime and checkpointing
• channels - Channel-based state storage and versioning
• reducers - State merge strategies and conflict resolution

Modules

app

channels

event_bus

graphs

Graph definition and compilation for workflow execution.

message

node

Node execution framework for the Weavegraph workflow system.

reducers

runtimes

Workflow runtime infrastructure for session management and state persistence.

schedulers

state

State management for the Weavegraph workflow framework.

telemetry

types

Core types for the Weavegraph workflow framework.

utils

Utilities module for common functionality across the Weavegraph framework.