雲監視中的 AWS S3 Lambda 縮略圖生成節點錯誤

Question

我的 lambda 函數沒有按預期生成縮略圖。 這是我的節點代碼。 我上傳了一個帶有節點模塊的 .zip 文件。

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

// constants
var MAX_WIDTH  = 250;
var MAX_HEIGHT = 250;

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

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

    // Sanity check: validate that source and destination are different buckets.
    if (srcBucket == dstBucket) {
        callback("Source and destination buckets are the same.");
        return;
    }

    // Infer the image type.
    var typeMatch = srcKey.match(/\.([^.]*)$/);
    if (!typeMatch) {
        callback("Could not determine the image type.");
        return;
    }
    var imageType = typeMatch[1].toLowerCase();
    if (imageType != "jpg" && imageType != "png") {
        callback(`Unsupported image type: ${imageType}`);
        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) {
                console.log('Width logggg' + size.width);
                console.log('height logggg' + size.height)
                // Infer the scaling factor to avoid stretching the image unnaturally.
                var scalingFactor = Math.min(

                    MAX_WIDTH / size.width,
                    MAX_HEIGHT / size.height
                );
                var width  = scalingFactor * size.width;
                var height = scalingFactor * size.height;

                // Transform the image buffer in memory.
                this.resize(width, height)
                    .toBuffer(imageType, function(err, buffer) {
                        if (err) {
                            next(err);
                        } else {
                            next(null, response.ContentType, buffer);
                        }
                    });
            });
        },
        function upload(contentType, data, next) {
            // Stream the transformed 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
                );
            }

            callback(null, "message");
        }
    );
};

我剛剛粘貼了此鏈接中的代碼

我在 Lambda、S3 觸發器和存儲桶名稱中實現了所有正確的內容。 但在 Cloudwatch 指標中，我收到此錯誤。

請告訴我我的錯誤。

如何修復此錯誤。

Answer 1

堆棧跟蹤顯示錯誤發生在文件/var/task/index.js的第 57 行第 38 列中，因此這是最好的起點。

如果我不得不猜測，如果我們假設transform函數是index.js函數，那么size可能沒有width屬性。 可能值得登錄那里看看發生了什么。

function transform(response, next) {
            gm(response.Body).size(function(err, size) {
                // Infer the scaling factor to avoid stretching the image unnaturally.
                var scalingFactor = Math.min(
                    MAX_WIDTH / size.width, // <-- here
                    MAX_HEIGHT / size.height
                );

不知道gm(response.Body).size()對其回調有何期望，但最好記錄在此處傳遞的參數。