aws-lambda-image

An AWS Lambda Function to resize/reduce images automatically. When an image is put on AWS S3 bucket, this package will resize/reduce it and put to S3.

Requirements

• Node.js ( AWS Lambda supports versions of 6.10 and 8.10 )

Preparation

Clone this repository and install dependencies:

git clone git@github.com:ysugimoto/aws-lambda-image.git
cd aws-lambda-image
npm install .

When upload to AWS Lambda, the project will bundle only needed files - no dev dependencies will be included.

Configuration

Configuration file you will find under the name config.json in project root. It's copy of our example file config.json.sample. More or less it looks like:

{
  "bucket": "your-destination-bucket",
  "backup": {
      "directory": "./original"
  },
  "reduce": {
      "directory": "./reduced",
      "prefix": "reduced-",
      "quality": 90,
      "acl": "public-read",
      "cacheControl": "public, max-age=31536000"
  },
  "resizes": [
    {
      "size": 300,
      "directory": "./resized/small",
      "prefix": "resized-",
      "cacheControl": null
    },
    {
      "size": 450,
      "directory": "./resized/medium",
      "suffix": "_medium"
    },
    {
      "size": "600x600^",
      "gravity": "Center",
      "crop": "600x600",
      "directory": "./resized/cropped-to-square"
    },
    {
      "size": 600,
      "directory": "./resized/600-jpeg",
      "format": "jpg",
      "background": "white"
    },
    {
      "size": 900,
      "directory": "./resized/large",
      "quality": 90
    }
  ]
}

Configuration Parameters

Note that the optmizers option will force override its command arguments, so if you define these configurations, we don't care any more about how optimizer works.

Testing Configuration

If you want to check how your configuration will work, you can use:

npm run test-config

Installation

Setup

To use the automated deployment scripts you will need to have aws-cli installed and configured.

Deployment scripts are pre-configured to use some default values for the Lambda configuration. I you want to change any of those just use:

npm config set aws-lambda-image:profile default
npm config set aws-lambda-image:region eu-west-1
npm config set aws-lambda-image:memory 1280
npm config set aws-lambda-image:timeout 5
npm config set aws-lambda-image:name lambda-function-name
npm config set aws-lambda-image:role lambda-execution-role

Note that aws-lambda-image:name and aws-lambda-image:role are optional. If you want to change lambda function name or execution role, type above commands before deploy.

Deployment

Command below will deploy the Lambda function on AWS, together with setting up roles and policies.

npm run deploy

Notice: Because there are some limitations in Claudia.js support for policies, which could lead to issues with Access Denied when processing images from one bucket and saving them to another, we have decided to introduce support for custom policies.

Custom policies

Policies which should be installed together with our Lambda function are stored in policies/ directory. We keep there policy that grants access to all buckets, which is preventing possible errors with Access Denied described above. If you have any security-related concerns, feel free to change the:

"Resource": [
    "*"
]

in the policies/s3-bucket-full-access.json to something more restrictive, like:

"Resource": [
    "arn:aws:s3:::destination-bucket-name/*"
]

Just keep in mind, that you need to make those changes before you do the deployment.

Adding S3 event handlers

To complete installation process you will need to take one more action. It will allow you to install S3 Bucket event handler, which will send information about all uploaded images directly to your Lambda function.

npm run add-s3-handler --s3_bucket="your-bucket-name" --s3_prefix="directory/" --s3_suffix=".jpg"

You are able to install multiple handlers per Bucket. So, to add handler for PNG files you just need to re-run above command with different suffix, ie:

npm run add-s3-handler --s3_bucket="your-bucket-name" --s3_prefix="directory/" --s3_suffix=".png"

Adding SNS message handlers

As an addition, you can also setup and SNS message handler in case you would like to process S3 events over an SNS topic.

npm run add-sns-handler --sns_topic="arn:of:SNS:topic"

Updating

To update Lambda with you latest code just use command below. Script will build new package and automatically publish it on AWS.

npm run update

More

For more scripts look into package.json.

Complete / Failed hooks

You can handle resize/reduce/backup process on success/error result on index.js. ImageProcessor::run will return Promise object, run your original code:

processor.run(config)
.then(function(proceedImages)) {
 
    // Success case:
    // proceedImages is list of ImageData instance on you configuration
 
    /* your code here */
 
    // notify lambda
    context.succeed("OK, numbers of " + proceedImages.length + " images has proceeded.");
})
.catch(function(messages) {
 
    // Failed case:
    // messages is list of string on error messages
 
    /* your code here */
 
    // notify lambda
    context.fail("Woops, image process failed: " + messages);
});

Image resize

• ImageMagick (installed on AWS Lambda)

Image reduce

• cjpeg
• jpegoptim
• pngquant
• gifsicle

License

MIT License.

Author

Yoshiaki Sugimoto

Image credits

Thanks for testing fixture images:

• pngimg
• pakutaso