Suspend and Resume

In AgentScope AI, workflows can be suspended and resumed to allow for asynchronous processing, waiting for external events, or handling long-running tasks. This capability ensures that workflows remain efficient and responsive without blocking execution resources.

Suspending a Workflow

A workflow can be suspended when it needs to wait for an external condition, such as a user input, an API response, or a time-based trigger. When suspended, the workflow state is saved so it can be resumed later.

Example: Suspending for User Input

import { Workflow, suspend } from "@agentscope/core";

export const approvalWorkflow = new Workflow({
  id: "approvalWorkflow",
  steps: [
    async (context) => {
      console.log("Waiting for user approval...");
      return suspend({ event: "user_approval", timeout: 3600 });
    },
    async (context) => {
      console.log("Approval received, continuing workflow.");
    },
  ],
});

In this example, the workflow suspends at the first step, waiting for a user_approval event. If the event is received, the workflow resumes. If the timeout expires, it can be handled separately.

Resuming a Workflow

A suspended workflow can be resumed when the expected event occurs. This is typically done through an external trigger, such as an API call or an event listener.

Example: Resuming a Workflow

import { resumeWorkflow } from "@agentscope/core";

// Simulate receiving a user approval event
const eventData = { userId: "123", decision: "approved" };
resumeWorkflow("approvalWorkflow", eventData);

Here, resumeWorkflow reactivates the workflow that was previously suspended.

Handling Timeouts

If a workflow is suspended with a timeout, it will automatically fail or execute a fallback step when the timeout expires.

Example: Handling Timeout

async function handleTimeout(context) {
  console.log("Timeout reached, taking alternative action.");
  return "Timeout fallback executed.";
}

export const approvalWorkflowWithTimeout = new Workflow({
  id: "approvalWorkflowWithTimeout",
  steps: [
    async (context) => {
      return suspend({ event: "user_approval", timeout: 3600, onTimeout: handleTimeout });
    },
  ],
});

If no event is received within 3600 seconds, handleTimeout executes to ensure the workflow doesn’t stall indefinitely.