How to Optimize Images in the Cloud

Using AWS S3 and Lambda

1. 
   Set up AWS S3. Get started with setting up your AWS S3 bucket if you haven't already created one. Amazon S3 lets you store any amount of data and up to 5GB for free. Check out the article on Upload to Amazon S3 to set up and configure your AWS S3 account. Once you are done with that, create two folders in your bucket, and name them original and resized. As the name suggests, the original directory stores the original image whereas resized directory stores the resized image.
2. Write the optimization code. We are going to use async, aws-sdk, gm, and path libs for the demo optimization code. You will need to install node and all the dependencies first and then copy the following code into imageResizer.js.

    // dependencies var async = require('async'); var AWS = require('aws-sdk'); var gm = require('gm') .subClass({ imageMagick: true }); // Enable ImageMagick integration. var util = require('util'); var path = require('path'); // constants var WEB_WIDTH_MAX = 150; var WEB_HEIGHT_MAX = 150; var imageResponse; // 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 imageName=path.basename(srcKey); var dstBucket = srcBucket; var imageResponse ; // Infer the image type. var typeMatch = srcKey.match(/.([^.]*)$/); if (!typeMatch) { callback("Could not determine the image type."); return; } var imageType = typeMatch[1]; if (imageType.toUpperCase() != "jpg".toUpperCase() && imageType.toUpperCase() != "png".toUpperCase() && imageType.toUpperCase() != "jpeg".toUpperCase()) { callback('Unsupported image type: ${imageType}'); return; } function uploadWebMax(response, buffer, next) { // Stream the transformed image to a different S3 bucket. var dstKeyResized = "resized/"+imageName; s3.putObject({ Bucket: dstBucket, Key: dstKeyResized, Body: buffer, ContentType: response.ContentType }, function(err, data) { if (err) { console.log(err, err.stack); }else{ console.log('uploaded to web-max Successfully !!'); next(null, response, buffer); } }); } 

3. Configure AWS Lambda. Next, you need to login to the AWS console and select Lambda from the services. From the Lambda page, select the `create the lambda function` button.
4. 
   Create a Lambda function for optimizing images. You will be asked to select a blueprint. Click on Blank function.

   1. Configure trigger. You will be asked to add a trigger that will invoke the lambda function. Choose S3 here.
   2. Select the bucket that we created earlier. Set the event type to Object created (All) and the prefix to original/. Press next.
   3. Choose a function name. Select zip for code entry and use the upload the zip that we created earlier. The alternate inline option can use if there aren't any dependencies.
5. Set up the IAM Roles. Now, you will need to fill in the handler name and the IAM role for Lambda. In 'Lambda function handler and role' field, change the name of the handler to imageResizer.js. The name of the js file inside our zip and the handler needs to match. From the Roles tab, select the option custom role. You can define new roles and add a policy here.
6. Done. From the final screen, press creation function button. Congratulations, you have successfully created a lambda function that optimizes an image and then moves it to the resized folder. You can POST new images to the original bucket and pull resized version of the image from the resized bucket.