Trait GraphCallbackHandler 

pub trait GraphCallbackHandler:
    Send
    + Sync
    + 'static {
    // Provided methods
    fn on_interrupt(&self, event: &GraphInterruptEvent) { ... }
    fn on_resume(&self, event: &GraphResumeEvent) { ... }
    fn on_checkpoint_saved(&self, checkpoint_id: &str, step: usize) { ... }
    fn on_node_start(&self, node: &str, task_id: &str) { ... }
    fn on_node_end(&self, node: &str, task_id: &str, duration_ms: u64) { ... }
    fn on_node_error(&self, node: &str, error: &JunctureError) { ... }
    fn on_graph_end(&self, result: &Result<(), JunctureError>) { ... }
}

Graph lifecycle callback trait

Implement this trait to receive notifications of important events during graph execution. All methods have default no-op implementations, so you only need to implement the events you care about.

Examples

use juncture_tracing::callback::{GraphCallbackHandler, GraphInterruptEvent};
use juncture_core::JunctureError;
use std::sync::Arc;

struct MyCallbackHandler;

impl GraphCallbackHandler for MyCallbackHandler {
    fn on_interrupt(&self, event: &GraphInterruptEvent) {
        // Handle interrupt - e.g., log to file or send metrics
        let _ = event;
    }

    fn on_graph_end(&self, result: &Result<(), JunctureError>) {
        // Handle completion - e.g., record final status
        let _ = result;
    }
}

Provided Methods

fn on_interrupt(&self, event: &GraphInterruptEvent)

Called when the graph is interrupted

This method is invoked when a node triggers an interrupt during execution.

Parameters

• event - Details about the interrupt event

fn on_resume(&self, event: &GraphResumeEvent)

Called when the graph resumes from an interrupt

This method is invoked when the graph continues execution after being interrupted.

Parameters

• event - Details about the resume event

fn on_checkpoint_saved(&self, checkpoint_id: &str, step: usize)

Called when a checkpoint is saved

This method is invoked after a checkpoint is successfully persisted.

Parameters

• checkpoint_id - Unique identifier for the checkpoint
• step - The step number at which this checkpoint was created

fn on_node_start(&self, node: &str, task_id: &str)

Called when a node starts execution

This method is invoked when a node begins processing.

Parameters

• node - Name of the node starting execution
• task_id - Unique identifier for this task instance

fn on_node_end(&self, node: &str, task_id: &str, duration_ms: u64)

Called when a node completes execution

This method is invoked when a node finishes processing successfully.

Parameters

• node - Name of the node that completed
• task_id - Unique identifier for this task instance
• duration_ms - Execution duration in milliseconds

fn on_node_error(&self, node: &str, error: &JunctureError)

Called when a node encounters an error

This method is invoked when a node fails during execution.

Parameters

• node - Name of the node that failed
• error - The error that occurred

fn on_graph_end(&self, result: &Result<(), JunctureError>)

Called when the graph execution completes

This method is invoked when the entire graph execution finishes, either successfully or with an error.

Parameters

• result - The final result of the graph execution

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl<T: GraphCallbackHandler + ?Sized> GraphCallbackHandler for Arc<T>

Blanket implementation for Arc<dyn GraphCallbackHandler>

This allows Arc<dyn GraphCallbackHandler> to be used directly as a callback handler.

fn on_interrupt(&self, event: &GraphInterruptEvent)

fn on_resume(&self, event: &GraphResumeEvent)

fn on_checkpoint_saved(&self, checkpoint_id: &str, step: usize)

fn on_node_start(&self, node: &str, task_id: &str)

fn on_node_end(&self, node: &str, task_id: &str, duration_ms: u64)

fn on_node_error(&self, node: &str, error: &JunctureError)

fn on_graph_end(&self, result: &Result<(), JunctureError>)

Implementors