javascript - Node.js 脚本工作一次，然后失败

Question

I need a Node.js script that does the following:

1 - Triggers when an image is added to a specified S3 bucket.
2 - Creates a thumbnail of that image (360x203 pixels).
3 - Saves a copy of that thumbnail inside of a separate S3 folder.
4 - Uploads the thumbnail to a specified FTP server, SIX (6) times using a "FILENAME-X"naming convention.

该代码最初按预期工作。示例事件拉取图像。创建一个缩略图。将其保存到另一个 S3 存储桶。然后上传到FTP服务器。

问题:它对测试文件 HappyFace.jpg 有效一次，但随后的每个后续测试都失败了。此外，我尝试使用不同的文件执行此操作，但未成功。

另外:如果我能得到一些帮助来编写一个循环来命名上传的不同文件，我将不胜感激。我通常使用 PHP 编写代码，因此我可能需要比我希望的更长的时间来编写代码。

注意:出于隐私考虑，我删除了我的 FTP 凭据。

问题代码片段:

    function upload(contentType, data, next) {
        // Upload test file to FTP server
        c.append(data, 'testing.jpg', function(err) {
            console.log("CONNECTION SUCCESS!");
            if (err) throw err;
            c.end();
        });
        // Connect to ftp
        c.connect({
            host: "",
            port: 21, // defaults to 21
            user: "", // defaults to "anonymous"
            password: "" // defaults to "@anonymous"
        });
        // S3 Bucket Upload Function Goes Here
    }

完整代码:

// dependencies
var async = require('async');
var AWS = require('aws-sdk');
var util = require('util');
var Client = require('ftp');
var fs = require('fs');
var gm = require('gm')
            .subClass({ imageMagick: true }); // Enable ImageMagick integration.

// get reference to FTP client
var c = new Client();
// get reference to S3 client 
var s3 = new AWS.S3();

exports.handler = function(event, context) {
    // Read options from the event.
    console.log("Reading options from event:\n", util.inspect(event, {depth: 5}));
    // Get source bucket
    var srcBucket = event.Records[0].s3.bucket.name;
    // Get source object key
    // Object key may have spaces or unicode non-ASCII characters.
    var srcKey    =
    decodeURIComponent(event.Records[0].s3.object.key.replace(/\+/g, " "));  
    var url = 'http://' + srcBucket + ".s3.amazonaws.com/" + srcKey;
    // Set destination bucket
    var dstBucket = srcBucket + "-thumbs";
    // Set destination object key
    var dstKey    = "resized-" + srcKey;

    // Infer the image type.
    var typeMatch = srcKey.match(/\.([^.]*)$/);
    if (!typeMatch) {
        console.error('unable to infer image type for key ' + srcKey);
        return;
    }
    var imageType = typeMatch[1];
    if (imageType != "jpg" && imageType != "png") {
        console.log('skipping non-image ' + srcKey);
        return;
    }

    // Download the image from S3, transform, and upload to a different S3 bucket.
    async.waterfall([
        function download(next) {
            // Download the image from S3 into a buffer.
            s3.getObject({
                    Bucket: srcBucket,
                    Key: srcKey
                },
                next);
            },
        function transform(response, next) {
            gm(response.Body).size(function(err, size) {

                // Transform the image buffer in memory.
                this.toBuffer(imageType, function(err, buffer) {
                        if (err) {
                            next(err);
                        } else {
                            next(null, response.ContentType, buffer);
                        }
                    });
            });
        },
        function upload(contentType, data, next) {
            // Upload test file to FTP server
            c.append(data, 'testing.jpg', function(err) {
                console.log("CONNECTION SUCCESS!");
                if (err) throw err;
                c.end();
            });
            // Connect to ftp
            c.connect({
                host: "",
                port: 21, // defaults to 21
                user: "", // defaults to "anonymous"
                password: "" // defaults to "@anonymous"
            });
            // Stream the thumb image to a different S3 bucket.
            s3.putObject({
                    Bucket: dstBucket,
                    Key: dstKey,
                    Body: data,
                    ContentType: contentType
                },
                next);
        }
        ], function (err) {
            if (err) {
                console.error(
                    'Unable to resize ' + srcBucket + '/' + srcKey +
                    ' and upload to ' + dstBucket + '/' + dstKey +
                    ' due to an error: ' + err
                );
            } else {
                console.log(
                    'Successfully resized ' + srcBucket + '/' + srcKey +
                    ' and uploaded to ' + dstBucket + '/' + dstKey
                );
            }

//          context.done();
        }
    );
};

日志:

START RequestId: edc808c1-712b-11e5-aa8a-ed7c188ee86c Version: $LATEST 
2015-10-12T21:55:20.481Z    edc808c1-712b-11e5-aa8a-ed7c188ee86c    Reading options from event: { Records:  [ { eventVersion: '2.0', eventTime: '1970-01-01T00:00:00.000Z', requestParameters: { sourceIPAddress: '127.0.0.1' }, s3:  { configurationId: 'testConfigRule', object:  { eTag: '0123456789abcdef0123456789abcdef', sequencer: '0A1B2C3D4E5F678901', key: 'HappyFace.jpg', size: 1024 }, bucket:  { arn: 'arn:aws:s3:::images', name: 'images', ownerIdentity: { principalId: 'EXAMPLE' } }, s3SchemaVersion: '1.0' }, responseElements:  { 'x-amz-id-2': 'EXAMPLE123/5678abcdefghijklambdaisawesome/mnopqrstuvwxyzABCDEFGH', 'x-amz-request-id': 'EXAMPLE123456789' }, awsRegion: 'us-east-1', eventName: 'ObjectCreated:Put', userIdentity: { principalId: 'EXAMPLE' }, eventSource: 'aws:s3' } ] } 
2015-10-12T21:55:22.411Z    edc808c1-712b-11e5-aa8a-ed7c188ee86c    Successfully resized images/HappyFace.jpg and uploaded to images-thumbs/resized-HappyFace.jpg 
2015-10-12T21:55:23.432Z    edc808c1-712b-11e5-aa8a-ed7c188ee86c    CONNECTION SUCCESS! 
END RequestId: edc808c1-712b-11e5-aa8a-ed7c188ee86c 
REPORT RequestId: edc808c1-712b-11e5-aa8a-ed7c188ee86c  Duration: 3003.76 ms    Billed Duration: 3000 ms Memory Size: 128 MB    Max Memory Used: 43 MB   
Task timed out after 3.00 seconds  
START RequestId: d347e7e3-712d-11e5-bfdf-05baa36d50fd Version: $LATEST 
2015-10-12T22:08:55.910Z    d347e7e3-712d-11e5-bfdf-05baa36d50fd    Reading options from event: { Records:  [ { eventVersion: '2.0', eventTime: '1970-01-01T00:00:00.000Z', requestParameters: { sourceIPAddress: '127.0.0.1' }, s3:  { configurationId: 'testConfigRule', object:  { eTag: '0123456789abcdef0123456789abcdef', sequencer: '0A1B2C3D4E5F678901', key: 'HappyFace.jpg', size: 1024 }, bucket:  { arn: 'arn:aws:s3:::images', name: 'images', ownerIdentity: { principalId: 'EXAMPLE' } }, s3SchemaVersion: '1.0' }, responseElements:  { 'x-amz-id-2': 'EXAMPLE123/5678abcdefghijklambdaisawesome/mnopqrstuvwxyzABCDEFGH', 'x-amz-request-id': 'EXAMPLE123456789' }, awsRegion: 'us-east-1', eventName: 'ObjectCreated:Put', userIdentity: { principalId: 'EXAMPLE' }, eventSource: 'aws:s3' } ] } 
END RequestId: d347e7e3-712d-11e5-bfdf-05baa36d50fd 
REPORT RequestId: d347e7e3-712d-11e5-bfdf-05baa36d50fd  Duration: 3003.33 ms    Billed Duration: 3000 ms Memory Size: 128 MB    Max Memory Used: 17 MB   
Task timed out after 3.00 seconds

Answer 1

行:

var c = new Client();

只会被执行一次；所有对 handler() 函数的调用都将使用您的 FTP 客户端的相同实例。

如果对 handler() 有多个重叠调用——在异步世界中，这似乎很有可能——那么对 FTP 客户端的调用，包括 c.connect(…) 和 c.end() 将针对 同一个 FTP 客户端调用多次，该客户端可能已经在进行上传，从而导致这样的场景:

1. 调用 handler()。上传开始。
2. 调用 handler()。第二次上传开始。
3. 第一次上传完成并调用c.end()。
4. 第二次上传已取消。

解决方案是为每次上传创建一个新的 FTP 客户端实例，或者，如果您的 FTP 服务器有问题(限制客户端连接数)，您需要以某种方式序列化您的上传。由于您使用的是 async 库，因此一种方法是使用 async.queue .