README.md

AWS Lambda Image Resize Example (with ImageMagick)

This repository deploys an AWS Lambda Function that resizes images using ImageMagick.

Blog post: https://www.bytescale.com/blog/aws-lambda-image-resize/

Quick Start

Important:

• Replace my-lambda-function-code and my-images with unique S3 bucket names!

Deploying the Lambda Function

1. Checkout the repository:

   git clone git@github.com:bytescale/aws-lambda-image-magick-resize-example.git
   
   cd aws-lambda-image-magick-resize-example

2. Install NPM dependencies:

   npm install

3. Create the S3 bucket stack (remember: change the bucket names in ParameterValue below):

   aws cloudformation create-stack \
     --stack-name my-bucket-stack \
     --parameters ParameterKey=LambdaCodeBucketName,ParameterValue=my-lambda-function-code \
                  ParameterKey=ImageBucketName,ParameterValue=my-images \
     --template-body file://buckets-cloudformation.yml

4. Update function.js > imageBucketName to your image bucket's name.

5. Upload the Lambda Function's code:

   zip -ry function-dist.zip .
   aws s3 cp function-dist.zip s3://my-lambda-function-code/AwsLambdaImageResizeExample.zip

6. Deploy the Lambda Function (remember: change the bucket names in ParameterValue below):

   aws cloudformation create-stack \
     --stack-name my-image-resize-lambda \
     --parameters ParameterKey=LambdaCodeBucketName,ParameterValue=my-lambda-function-code \
                  ParameterKey=ImageBucketName,ParameterValue=my-images \
     --template-body file://function-cloudformation.yml \
     --capabilities CAPABILITY_NAMED_IAM

7. Wait for the Lambda Function's stack to complete:

   aws cloudformation describe-stack-events \
     --stack-name my-image-resize-lambda

   Note: the latest event should read "ResourceStatus": "CREATE_COMPLETE".

Invoking the function

1. Upload the image to resize:

   aws s3 cp test-image.jpg s3://my-images/original-image.jpg

2. Invoke the function:

   aws lambda invoke \
     --function-name AwsLambdaImageResizeExample \
     function-result.json

3. "See" the result:

   cat function-result.json

   Outputs:

   {
     "isBase64Encoded": true,
     "statusCode": 200,
     "headers": {
       "content-type": "image/jpg"
     },
     "body": "/9j/4AAQSkZJRg...9k="
   }

   Note: AWS Lambda only supports JSON responses. body contains the resized image as a base64-encoded string: to return the raw image, you'll need to put API Gateway in front of the Lambda function.