@1999/scheduler 中文文档教程
Scheduler
用于使用 Typescript 编写的定期任务的 Node.js 库。
How to install
npm install @1999/scheduler --save
API
scheduler 的唯一概念是 Task
,代表一个周期性运行的任务。 它应该是一个回调,应该返回一个 Promise。
Simple tasks
使用 scheduler.addTask(task: Task, period: number)
函数设置任务周期。
import {
default as Scheduler,
Task,
} from '@1999/scheduler';
const task: Task = () => Promise.resolve(2);
const scheduler = new Scheduler();
scheduler.addTask(task, 1000);
scheduler.start();
Named tasks
在这种情况下,您可以在调度程序构造函数中传递任务组。 然后使用 scheduler.addTask(task: Task, periodId: string)
函数将任务分配给任务组。
import {
default as Scheduler,
Task,
} from '@1999/scheduler';
const task1: Task = () => got('https://api.facebook/id/1');
const task2: Task = () => got('https://api.facebook/id/2');
const scheduler = new Scheduler({ api: 1000 });
scheduler.addTask(task1, 'api');
scheduler.addTask(task2, 'api');
scheduler.start();
When period should depend on task execution
有时仅仅有任务的执行周期是不够的。 例如,当您有一个允许您每 N 秒发出一次请求的 API 时:在这种情况下,在您收到上一个请求的响应后仅 N 秒发送下一个请求会更安全。 为此,您可以使用 Marker
回调,它是 Task
的唯一参数:
import {
default as Scheduler,
Marker,
Task,
} from '@1999/scheduler';
const task: Task = (marker: Marker) => {
return got('https://api.facebook/id/1').then(() => {
// you can run marker function anywhere inside your task
// and the period pause will be started from this moment
marker();
});
};
const scheduler = new Scheduler();
scheduler.addTask(task);
scheduler.start();
Events
Scheduler instance extends node.js EventEmitter。 您可以使用它来订阅 Scheduler 实例中发生的事件:
taskCompleted
- emits when task is successfully finished. Also emits an object{ name: string, execTime: number }
where runTime is the task execution time in milliseconds.taskFailed
- emits when task execution fails. Also emits an object{ err: Error, execTime: number, name: string }
Scheduler
Node.js library for periodical tasks written in Typescript.
How to install
npm install @1999/scheduler --save
API
The only concept of scheduler is a Task
which represents a periodically run task. It should be a callback which should return a Promise.
Simple tasks
Use scheduler.addTask(task: Task, period: number)
function to set up task period.
import {
default as Scheduler,
Task,
} from '@1999/scheduler';
const task: Task = () => Promise.resolve(2);
const scheduler = new Scheduler();
scheduler.addTask(task, 1000);
scheduler.start();
Named tasks
In this case you can pass task groups in scheduler constructor. Then use scheduler.addTask(task: Task, periodId: string)
function to assign task to task group.
import {
default as Scheduler,
Task,
} from '@1999/scheduler';
const task1: Task = () => got('https://api.facebook/id/1');
const task2: Task = () => got('https://api.facebook/id/2');
const scheduler = new Scheduler({ api: 1000 });
scheduler.addTask(task1, 'api');
scheduler.addTask(task2, 'api');
scheduler.start();
When period should depend on task execution
Sometimes it's not enough to have execution periodicity for tasks. For instance when you have an API which allows you to make requests once per N seconds: in this case it can be safer to send next request only N seconds after you get the response from the previous request. For this purpose you can use Marker
callback which is the only argument for Task
:
import {
default as Scheduler,
Marker,
Task,
} from '@1999/scheduler';
const task: Task = (marker: Marker) => {
return got('https://api.facebook/id/1').then(() => {
// you can run marker function anywhere inside your task
// and the period pause will be started from this moment
marker();
});
};
const scheduler = new Scheduler();
scheduler.addTask(task);
scheduler.start();
Events
Scheduler instance extends node.js EventEmitter. You can use it to subscribe to events happening inside Scheduler instance:
taskCompleted
- emits when task is successfully finished. Also emits an object{ name: string, execTime: number }
where runTime is the task execution time in milliseconds.taskFailed
- emits when task execution fails. Also emits an object{ err: Error, execTime: number, name: string }