image-lambda

An AWS Lambda function that AWS S3 can invoke to create thumbnails or reduce file size for png and jpg images.

Features:

• Reduce jpg/png file size. Image file size is reduced by more than 70%.
• PNG files with 100% support for transparency.
• Resize jpg/png based on configuration.

Dependencies

• node, version: 8.10
• docker, Required to build the deployment zip package.

How it works

Once you deployed image-lambda package to AWS Lambda and configured it. When an image is uploaded to AWS S3 bucket, S3 sends an notification to AWS Lambda and invokes the image-lambda function. image-lambda reduce/resize the image based on configuration and then put the processed images to target bucket/directory.

image-lambda use GraphicsMagick to resize image, and imagemin to reduce image file size.

Installation

git clone https://github.com/SlimFancy/image-lambda.git
cd image-lambda
node docker-npm.js install
serverless deploy

Configuration

image-lambda supports configuration for reduce/resize image. There is config.json.sample in project root directory as example. You can copy to use it.

$ cp config.json.example config.json

Here is an example of configuration:

{
  "reduce": {
    "sourceDir": "images/uploads",
    "targetBucket": "example",
    "targetDir": "images/reduce",
    "ACL": "public-read"
  },
  "resizes": [
    {
      "width": 100,
      "sourceDir": "images/uploads",
      "targetBucket": "example",
      "targetDir": "images/100w",
      "ACL": "public-read"
    },
    {
      "height": 200,
      "sourceDir": "images/uploads",
      "targetBucket": "example",
      "targetDir": "images/200h",
      "ACL": "public-read"
    },
    {
      "height": 200,
      "width": 200,
      "resizeOption": "^",
      "sourceDir": "images/uploads",
      "targetBucket": "example",
      "targetDir": "images/200",
      "format": "jpg",
      "ACL": "public-read"
    }
  ]
}

• reduce: Define params for reduce image.
• resizes: Define different image sizes. This example creates 3 thumbnails with different sizes.
• sourceDir/targetDir: For example, the uploaded image S3 key is "images/uploads/test-images/test.jpg", you want to generate a reduced image to directory images/reduce, so you can configure sourceDir=images/uploads and targetDir=images/reduce. Thus, you will get a reduced image with key "images/reduce/test-images/test.jpg". image-lambda replace the sourceDir in image s3 key with the targetDir.
• ACL: private | public-read | public-read-write | authenticated-read | aws-exec-read | bucket-owner-read | bucket-owner-full-control. Controls the permission of generated images.
• targetBucket: (Optionally) Specify the bucket where you want to put the generated images. If omitted will use the same bucket as the source image.
• width/height: It's better to just specify one of them, the other side can be resized based on the ratio.
• resizeOption: For resizing images, this optional parameter can be set to one of the ImageMagick geometry operators.
• format: specify a different output format for the image (this parameter only valid for for resizes).

Deploy using serverless

This now uses the serverless framework to deploy the code.

serverless deploy

A few caveats:

• At the moment I haven't parameterised this, so the source directory needs to match between serverless.yml and config.json, also the bucket name is manually specified at several locations in serverless.yml.
• The bucket can't already exist prior to the first deploy even in your own account. On my todo list is to review https://github.com/matt-filion/serverless-external-s3-event as a workaround for that.

Contributing

If you'd like to contribute to the project, feel free to submit a PR.

Run tests:

$ npm test

test/fixture directory contains jpg and png images for testing. After you run tests, the reduced and resized images are stored in test/out.

License

MIT