Long-Running Node Implementation

This document describes the implementation details of long-running nodes in the Floxide framework.

Overview

Long-running nodes in Floxide provide support for tasks that may take significant time to complete, with proper progress tracking and cancellation support.

Core Components

LongRunningNode Trait

The LongRunningNode trait defines the core interface for long-running tasks:

#[async_trait]
pub trait LongRunningNode<Context, Action>: Send + Sync
where
    Context: Send + Sync + 'static,
    Action: ActionType + Send + Sync + 'static + Debug,
{
    async fn start(&self, ctx: &mut Context) -> Result<(), FloxideError>;
    async fn check_progress(&self, ctx: &mut Context) -> Result<Progress, FloxideError>;
    async fn cancel(&self, ctx: &mut Context) -> Result<(), FloxideError>;
    fn id(&self) -> NodeId;
}

Progress Tracking

The Progress enum represents the current state of a long-running task:

pub enum Progress {
    Running(f32), // 0.0 to 1.0
    Complete(Action),
    Failed(FloxideError),
}

Implementation Details

Task Management

  1. Execution Control
  2. Task initialization
  3. Progress monitoring

  4. Graceful cancellation

  5. State Management

  6. Progress tracking
  7. State persistence

  8. Recovery mechanisms

  9. Resource Control

  10. Resource allocation
  11. Cleanup procedures
  12. Memory management

Error Handling

  1. Execution Errors
  2. Error propagation
  3. Recovery strategies

  4. Error reporting

  5. Cancellation Handling

  6. Safe cancellation
  7. Resource cleanup
  8. State consistency

Resource Management

  1. Memory Usage
  2. Efficient state tracking
  3. Resource cleanup

  4. Memory leak prevention

  5. Thread Safety

  6. Thread-safe execution
  7. Safe progress updates
  8. Proper synchronization

Usage Patterns

Basic Usage

let node = LongRunningTask::new(
    |ctx| { /* start implementation */ },
    |ctx| { /* progress check implementation */ },
    |ctx| { /* cancellation implementation */ },
);

With Progress Tracking

let node = LongRunningTask::new(
    |ctx| async {
        for i in 0..100 {
            process_chunk(i)?;
            update_progress(i as f32 / 100.0);
        }
        Ok(())
    },
    |ctx| async {
        let progress = get_current_progress();
        if progress >= 1.0 {
            Ok(Progress::Complete(DefaultAction::Next))
        } else {
            Ok(Progress::Running(progress))
        }
    },
    |ctx| async { /* cancellation implementation */ },
);

With Error Handling

let node = LongRunningTask::new(
    |ctx| async {
        if let Err(e) = check_preconditions() {
            return Err(e.into());
        }
        start_processing()
    },
    |ctx| async {
        match check_task_progress() {
            Ok(progress) => Ok(Progress::Running(progress)),
            Err(e) => Ok(Progress::Failed(e.into())),
        }
    },
    |ctx| async {
        cleanup_resources()?;
        Ok(())
    },
);

Testing

The implementation includes comprehensive tests:

  1. Unit Tests
  2. Task execution
  3. Progress tracking
  4. Cancellation handling

  5. Resource cleanup

  6. Integration Tests

  7. Complex workflows
  8. Error scenarios
  9. Performance tests

Performance Considerations

  1. Execution Efficiency
  2. Minimal overhead
  3. Efficient progress tracking

  4. Resource optimization

  5. Memory Usage

  6. Optimized state storage
  7. Efficient progress updates
  8. Minimal allocations

Future Improvements

  1. Enhanced Features
  2. More progress metrics
  3. Advanced cancellation strategies

  4. Extended recovery options

  5. Performance Optimizations

  6. Improved state tracking
  7. Better resource utilization
  8. Enhanced concurrency