如何在第一次失败后停止async.queue？
我想在发生第一个任务错误后停止执行我的async.queue。 我需要在并发限制的同时执行几个类似的操作，但是在第一个错误之后停止所有的操作。 我该怎么做，或者我应该使用什么？
假设你开了5个并行函数，每个函数都需要5秒钟。 在3秒钟内，function1失败。 那你怎么能停止其余的执行呢？
这取决于这些函数做什么，你可以使用setInterval进行轮询。 但是如果你的问题是如何阻止进一步的任务被推入队列。 你可以这样做：
q.push(tasks, function (err) { if (err && !called) { //Will prevent async to push more tasks to the queue, however please note that //whatever pushed to the queue, it will be processed anyway. q.kill(); //This will not allow double calling for the final callback called = true; //This the main process callback, the final callback main(err, results); } });
这里有一个完整的实例：
var async = require('async'); /* This function is the actual work you are trying to do. Please note for example if you are running child processes here, by doing q.kill you will not stop the execution of those processes, so you need actually to keep track the spawned processed and then kill them when you call q.kill in 'pushCb' function. In-case of just long running function, you may poll using setInterval */ function worker(task, wcb) { setTimeout(function workerTimeout() { if (task === 11 || task === 12 || task === 3) { return wcb('error in processing ' + task); } wcb(null, task + ' got processed'); }, Math.floor(Math.random() * 100)); } /* This function that will push the tasks to async.queue, and then hand them to your worker function */ function process(tasks, concurrency, pcb) { var results = [], called = false; var q = async.queue(function qWorker(task, qcb) { worker(task, function wcb(err, data) { if (err) { return qcb(err); //Here how we propagate error to qcb } results.push(data); qcb(); }); }, concurrency); /* The trick is in this function, note that checking q.tasks.length does not work q.kill introduced in async 0.7.0, it is just setting the drain function to null and the tasks length to zero */ q.push(tasks, function qcb(err) { if (err && !called) { q.kill(); called = true; pcb(err, results); } }); q.drain = function drainCb() { pcb(null, results); } } var tasks = []; var concurrency = 10; for (var i = 1; i <= 20; i += 1) { tasks.push(i); } process(tasks, concurrency, function pcb(err, results) { console.log(results); if (err) { return console.log(err); } console.log('done'); });
async.queue（）方法返回的队列对象时，github页面上的asynchronous文档是过时或不正确，我看不到方法kill（）。
尽pipe如此，还是有办法的。 队列对象有属性任务是一个数组，简单地分配一个空数组的引用做了我的诡计。
queue.push( someTasks, function ( err ) { if ( err ) queue.tasks = []; });