javascript - 为什么第 27 行在第 24 行之前执行？

Question

我是 javascript 的初学者，并尝试构建一个干净的对象以在我的用例中使用 Dockerode 库。我这里有一个异步问题，我的第 27 行在第 24 行之前执行，我不明白为什么以及如何解决它!

此外，如果它对您来说更容易，请访问此公共(public)要点:https://gist.github.com/msitruk/2cdb655a0bebdb29c61d8bc5606a2695

const Docker = require('dockerode');
const docker = new Docker({
    socketPath: '/var/run/docker.sock'
});

// CONSTRUCTOR
function SearchUtils() {
    this.listContainersPromise = docker.listContainers({all: true});
    this.scraperListId = [];
}

// "METHODS"
SearchUtils.prototype.run = function() {
    this.getScraperContainersListPromise()
        .then((containers) => {
            for (let i = 0; i < containers.length; i++) {
                if (containers[i].Names.toString().indexOf("scraper") !== -1) {
                    this.addToScraperList(containers[i].Id, "wait");
                }
            }
        }, (err)=>{console.log(err)})
        .then(()=>{
            this.checkReadyScraper();
        },(err)=>{console.log(err)})
        .then(() => {
            this.scrap();
        }, (err)=>{console.log(err)});
};

SearchUtils.prototype.checkReadyScraper = function() {
    for (let i = 0; i < this.scraperListId.length; i++) {
        this.exec("getStatus", this.scraperListId[i].id);
    }
};

SearchUtils.prototype.getScraperContainersListPromise = function() {
    return this.listContainersPromise; // <- Not working
};

SearchUtils.prototype.exec = function(type, containerId){
    let container = docker.getContainer(containerId);
    if (type === "getStatus"){
        this.runExec(container, 'cat /home/immobot/status');
    }
    else if (type === "scrap") {
        this.runExec(container, 'torify scrapy crawl seloger -o seloger.json');
    }
};

SearchUtils.prototype.scrap = function() {
    let localRdyScraperList = [];
    for (let i = 0; i < this.scraperListId.length; i++) {
        if(this.scraperListId[i].status.toString('utf8').indexOf("ready") !== -1){
            localRdyScraperList.push(this.scraperListId[i].id);
        }
    }
    console.log("test de localRdyScraperList : "+localRdyScraperList);
    // this.exec("scrap", this.scraperListId[i].id);
};

SearchUtils.prototype.addToScraperList = function(containerId,status) {
    this.scraperListId.push({id: containerId, status: status});
};

SearchUtils.prototype.getScraperList = function() {
    return this.scraperListId;
};

SearchUtils.prototype.getScraperList = function() {
    return this.scraperListId;
};

SearchUtils.prototype.runExec = function (container, cmd) {
    let options = {
        Cmd: [ '/bin/bash', '-c', cmd ],
        AttachStdout: true,
        AttachStderr: true
    };

    container.exec(options, (err, exec) => {
        if (err) return;
        exec.start((err, stream) => {
            if (err){
                console.log("error : "+err);
                return;
            }

            // container.modem.demuxStream(stream, process.stdout, process.stderr)

            if (cmd === "cat /home/immobot/status"){
                let newStream = require('stream');
                let logStream = new newStream.PassThrough();
                logStream.on('data', (chunk) => {
                    // console.log(chunk.toString('utf8'));
                    if (chunk.toString('utf8').indexOf("ready") !== -1){
                        console.log("CONTAINER READY !!");
                        //EDIT CONTAINER STATUS IN SCRAPERLIST TO READY
                        this.changeStatusToReady(container.id);
                    }
                });
                container.modem.demuxStream(stream, logStream, process.stderr);

            }
            else if (cmd === "torify scrapy crawl seloger -o seloger.json"){
                console.log("on lance le scrape sur un des scraper rdy");
                container.modem.demuxStream(stream, process.stdout, process.stderr)
            }

            // container.modem.demuxStream(stream, logStream, process.stderr);

            exec.inspect(function(err, data) {
                if (err){
                    console.log("error : "+err);
                    return;
                }
            });
        });
    });
};

SearchUtils.prototype.changeStatusToReady = function (containerId){
    for (let i = 0; i < this.scraperListId.length; i++) {
        if(this.scraperListId[i].id === containerId){
            this.scraperListId[i].status = "ready";
        }
    }
    // console.log(this.getScraperList());
};

module.exports = SearchUtils;

Answer 1

如果您的链接 promise ，请不要忘记返回您的下一个 promise ..

例如..

.then(()=>{
  this.checkReadyScraper();
}

如果 checkReadyScraper() 是一个 promise ，那么你会想要返回它。

例如。

.then(()=>{
  return this.checkReadyScraper();
}

否则你所做的就是运行 checkReadyScraper() 并完全忽略返回的 Promise。

我认为您的 runExec 应该是这样的。我假设 exec.inspect 是您要解决的问题。

SearchUtils.prototype.runExec = function (container, cmd) {
    return new Promise ((resolve, reject)=>{
        let options = {
            Cmd: [ '/bin/bash', '-c', cmd ],
            AttachStdout: true,
            AttachStderr: true
        };

        container.exec(options, (err, exec) => {
            if (err) return reject(err); //return error
            exec.start((err, stream) => {
                if (err){
                    console.log("error : "+err);
                    return reject(err); //return error
                }

                // container.modem.demuxStream(stream, process.stdout, process.stderr)

                if (cmd === "cat /home/immobot/status"){
                    let newStream = require('stream');
                    let logStream = new newStream.PassThrough();
                    logStream.on('data', (chunk) => {
                        // console.log(chunk.toString('utf8'));
                        if (chunk.toString('utf8').indexOf("ready") !== -1){
                            console.log("CONTAINER READY !!");
                            //EDIT CONTAINER STATUS IN SCRAPERLIST TO READY
                            this.changeStatusToReady(container.id);
                        }
                    });
                    container.modem.demuxStream(stream, logStream, process.stderr);

                }
                else if (cmd === "torify scrapy crawl seloger -o seloger.json"){
                    console.log("on lance le scrape sur un des scraper rdy");
                    container.modem.demuxStream(stream, process.stdout, process.stderr)
                }

                // container.modem.demuxStream(stream, logStream, process.stderr);

                exec.inspect(function(err, data) {
                    if (err){
                        console.log("error : "+err);
                        //don't forget to return the rejection
                        return reject(err);
                    }
                    //looks like everything was ok, lets resolve
                    resolve(data);
                });
            });
        });
        //resolve("ok"); too early
        // TODO ADD EROR STRATEGY
        //reject("error"), pointless
    });
};