Interface WorkflowInterceptor

Workflow interceptor that can wrap workflow execution in an onion-like pattern. Each interceptor wraps the next one, with the actual workflow execution at the center.

Interceptors are executed in the order they are registered. Each interceptor can:

  • Perform actions before workflow execution
  • Modify or enhance the workflow context
  • Handle or transform workflow results
  • Catch and handle errors
  • Add cross-cutting concerns like logging, metrics, or tracing

Example

// Simple logging interceptor
const loggingInterceptor: WorkflowInterceptor = {
  async execute(ctx, next) {
    console.log('Before workflow');
    try {
      const result = await next();
      console.log('After workflow');
      return result;
    } catch (err) {
      console.error('Workflow error:', err);
      throw err;
    }
  }
};

// Register the interceptor
MemFlow.registerInterceptor(loggingInterceptor);
interface WorkflowInterceptor {
    execute(ctx: Map<string, any>, next: (() => Promise<any>)): Promise<any>;
}

Methods

execute

Methods

execute

  • execute(ctx, next): Promise<any>

  • Called before workflow execution to wrap the workflow in custom logic

    Parameters

    • ctx: Map<string, any>

      The workflow context map containing workflow metadata and state

    • next: (() => Promise<any>)

      Function to call the next interceptor or the workflow itself

        • (): Promise<any>

        • Returns Promise<any>

    Returns Promise<any>

    The result of the workflow execution

    Example

    // Metrics interceptor implementation
    {
      async execute(ctx, next) {
        const workflowName = ctx.get('workflowName');
        const metrics = getMetricsClient();

        metrics.increment(`workflow.start.${workflowName}`);
        const timer = metrics.startTimer();

        try {
          const result = await next();
          metrics.increment(`workflow.success.${workflowName}`);
          return result;
        } catch (err) {
          metrics.increment(`workflow.error.${workflowName}`);
          throw err;
        } finally {
          timer.end();
        }
      }
    }

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