@penkov/tasks_queue/dist/multi-step-task.js

A lightweight PostgreSQL-backed task queue system with scheduling, retries, backoff strategies, and priority handling. Designed for efficiency and observability in modern Node.js applications.

import { MultiStepPayload } from "./multi-step-payload.js";
import { none, some } from "scats";
import { TaskStatus } from "./tasks-model.js";
import { TasksWorker } from "./tasks-worker.js";
export class MultiStepTask extends TasksWorker {
    async handleResolvedChild(payload, activeChild, childTask, context) {
        context.resolvedChildTask = some(childTask);
        const nextPayload = payload.copy({
            activeChild: none,
        });
        context.setPayload(nextPayload.toJson);
        if (childTask.status === TaskStatus.finished) {
            await this.childFinished(nextPayload, childTask, context, activeChild);
        }
        else if (childTask.status === TaskStatus.error) {
            await this.childFailed(nextPayload, childTask, context, activeChild);
        }
        else {
            throw new Error(`Inconsistent workflow state: child task with id=${childTask.id} is not terminal (status=${childTask.status})`);
        }
    }
    async childFinished(payload, _childTask, context, _activeChild) {
        await this.processNext(payload, context);
    }
    async childFailed(payload, childTask, _context, _activeChild) {
        const childError = childTask.error === undefined ? "Unknown error" : childTask.error;
        throw new Error(`Child task ${childTask.id} failed: ${childError}`);
    }
    async process(payload, context) {
        const typedPayload = MultiStepPayload.fromJson(payload);
        await typedPayload.activeChild.match({
            some: async (activeChild) => {
                const childTask = await context.findTask(activeChild.taskId);
                await childTask.match({
                    some: async (task) => {
                        await this.handleResolvedChild(typedPayload, activeChild, task, context);
                    },
                    none: async () => {
                        throw new Error(`Child task with id=${activeChild.taskId} not found`);
                    },
                });
            },
            none: async () => {
                await this.processNext(typedPayload, context);
            },
        });
    }
}