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AWS Lambda - S3 : Thumbnail creation
// dependencies
var async = require('async');
var path = require('path');
var AWS = require('aws-sdk');
var gm = require('gm').subClass({
imageMagick: true
});
var util = require('util');
// 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
}));
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 + "-output";
// Sanity check: validate that source and destination are different buckets.
if (srcBucket == dstBucket) {
console.error("Destination bucket must not match source bucket.");
return;
}
var _800px = {
width: 800,
dstnKey: srcKey,
destinationPath: "large"
};
var _500px = {
width: 500,
dstnKey: srcKey,
destinationPath: "medium"
};
var _200px = {
width: 200,
dstnKey: srcKey,
destinationPath: "small"
};
var _45px = {
width: 45,
dstnKey: srcKey,
destinationPath: "thumbnail"
};
var _sizesArray = [_800px, _500px, _200px, _45px];
var len = _sizesArray.length;
console.log(len);
console.log(srcBucket);
console.log(srcKey);
// Infer the image type.
var typeMatch = srcKey.match(/\.([^.]*)$/);
var fileName = path.basename(srcKey);
if (!typeMatch) {
console.error('unable to infer image type for key ' + srcKey);
return;
}
var imageType = typeMatch[1].toLowerCase();
if (imageType != "jpg" && imageType != "gif" && imageType != "png" &&
imageType != "eps") {
console.log('skipping non-image ' + srcKey);
return;
}
// Transform, and upload to same S3 bucket but to a different S3 bucket.
async.forEachOf(_sizesArray, function(value, key, callback) {
async.waterfall([
function download(next) {
console.time("downloadImage");
console.log("download");
// Download the image from S3 into a buffer.
// sadly it downloads the image several times, but we couldn't place it outside
// the variable was not recognized
s3.getObject({
Bucket: srcBucket,
Key: srcKey
}, next);
console.timeEnd("downloadImage");
},
function convert(response, next) {
// convert eps images to png
console.time("convertImage");
console.log("Reponse content type : " +
response.ContentType);
console.log("Conversion");
gm(response.Body).antialias(true).density(
300).toBuffer('JPG', function(err,
buffer) {
if (err) {
//next(err);
next(err);
} else {
console.timeEnd(
"convertImage");
next(null, buffer);
//next(null, 'done');
}
});
},
function process(response, next) {
console.log("process image");
console.time("processImage");
// Transform the image buffer in memory.
//gm(response.Body).size(function(err, size) {
gm(response).size(function(err, size) {
//console.log("buf content type " + buf.ContentType);
// Infer the scaling factor to avoid stretching the image unnaturally.
console.log("run " + key +
" size array: " +
_sizesArray[key].width);
console.log("run " + key +
" size : " + size);
console.log(err);
var scalingFactor = Math.min(
_sizesArray[key].width /
size.width, _sizesArray[
key].width / size.height
);
console.log("run " + key +
" scalingFactor : " +
scalingFactor);
var width = scalingFactor *
size.width;
var height = scalingFactor *
size.height;
console.log("run " + key +
" width : " + width);
console.log("run " + key +
" height : " + height);
var index = key;
//this.resize({width: width, height: height, format: 'jpg',})
this.resize(width, height).toBuffer(
'JPG', function(err,
buffer) {
if (err) {
//next(err);
next(err);
} else {
console.timeEnd(
"processImage"
);
next(null,
buffer,
key);
//next(null, 'done');
}
});
});
},
function upload(data, index, next) {
console.time("uploadImage");
console.log("upload : " + index);
console.log("upload to path : /images/" +
_sizesArray[index].destinationPath +
"/" + fileName.slice(0, -4) +
".jpg");
// Stream the transformed image to a different folder.
s3.putObject({
Bucket: dstBucket,
Key: "images/" + _sizesArray[
index].destinationPath +
"/" + fileName.slice(0, -4) +
".jpg",
Body: data,
ContentType: 'JPG'
}, next);
console.timeEnd("uploadImage");
}
], function(err, result) {
if (err) {
console.error(err);
}
// result now equals 'done'
console.log("End of step " + key);
callback();
});
}, function(err) {
if (err) {
console.error('---->Unable to resize ' + srcBucket +
'/' + srcKey + ' and upload to ' + dstBucket +
'/images' + ' due to an error: ' + err);
} else {
console.log('---->Successfully resized ' + srcBucket +
' and uploaded to' + dstBucket + "/images");
}
context.done();
});
};
@Jeff-P

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@Jeff-P Jeff-P commented Apr 16, 2016

I am getting an error when running this code, its unable to import imageSyncing

screenshot 2016-04-15 21 38 43

@Jlaird

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@Jlaird Jlaird commented Aug 4, 2016

I am also getting this error, Jeff did you figure this out?

@Jlaird

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@Jlaird Jlaird commented Aug 5, 2016

In case anyone else finds this and is wondering how to fix it. My Issue was cased by permissions, Lambda did not have permissions by default to access node_modules.

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