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Lambda Image Resize

Description

An AWS Lambda function for resizing images on demand.

Built using the sharp image resizing JS library, and running on the Node.js runtime.

Note: currently Sharp is being built on Node.js version 20.x

On invocation, the Lambda function will fetch the image from the 'original' S3 bucket, resize the image, upload both the original and the resized image to the target S3 bucket, and return the resulting filenames to a specified CallbackURL.

It is possible to pass via the function event param several versions of the image to be created and, also, several S3 buckets to store the images into.

Prerequisites

AWS credentials and config files with a default or named profile, which should be located in the ~/ .aws folder.

You should have the following packages locally installed:

  • Docker;

  • Python 3.xx and pip3 (the latter is installed along with the former);

  • AWS CLI: run $ pip3 install awscli --upgrade --user to install it;

    • Mac OS note: ~/Library/Python/3.xx/bin folder should be added to the path for aws to be find from the CLI

  • The sharp image resizing library;

  • The AWS SAM Local CLI tool for local development and testing.

Usage

Build Sharp

On Linux, the following simple command should just work:

$ yarn add sharp

On MacOS:

  • for local testing use the same yarn add sharp command
  • for deploying to AWS Lamda, Sharp should be compiled for Linux x64:
# SHARP_IGNORE_GLOBAL_LIBVIPS=1 npm_config_arch=x64 npm_config_platform=linux yarn add sharp

Local testing

To invoke and debug locally:

$ node test/lambda_start.js

Or, install globally the AWS SAM Local package.

$ npm install -g aws-sam-local

The AWS SAM Local invokation, described below, was based on the docker package https://github.com/lambci/docker-lambda, which now is pretty abandoned and of no use for now. There is a fork, if someone still need it, though it is not supported by the AWS SAM:

To invoke the Lambda function using the AWS SAM Local with an AWS credentials profile with a event.json fixture file, run the following command:

$ sam local invoke "ImageResizeOnDemand" -e test/event.json --profile texpert

Deploying

First, create a deploy package and upload it to a S3 bucket:

$ sam package --template-file template.yaml --s3-bucket texpert-test-store --s3-prefix lambda/packages --output-template-file packaged.yaml --profile texpert

The created packaged.yaml file will contain the URL to the S3 bucket, which was specified in the 'package' command.

Then, deploy the package to AWS CloudFormation stack:

# CAPABILITY_IAM is not a placeholder 
$ sam deploy --template-file ./packaged.yaml --stack-name lambda-test --capabilities CAPABILITY_IAM --profile texpert

Grant Lambda function access to the S3 buckets:

See https://aws.amazon.com/premiumsupport/knowledge-center/lambda-execution-role-s3-bucket/ and https://bobbyhadz.com/blog/aws-grant-lambda-access-to-s3

Create an IAM role for the Lambda function that also grants access to the S3 bucket

  1. Follow the steps in Creating an execution role in the IAM console.
  2. From the list of IAM roles, choose the role that you just created.
  3. In the Permissions tab, choose Add inline policy.
  4. Choose the JSON tab.
  5. Enter a resource-based IAM policy that grants access to your S3 bucket

Example of resource based IAM Policy:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "VisualEditor0",
            "Effect": "Allow",
            "Action": [
                "s3:PutAnalyticsConfiguration",
                "s3:GetObjectVersionTagging",
                "s3:CreateBucket",
                "s3:ReplicateObject",
                "s3:GetObjectAcl",
                "s3:GetBucketObjectLockConfiguration",
                "s3:DeleteBucketWebsite",
                "s3:GetIntelligentTieringConfiguration",
                "s3:PutLifecycleConfiguration",
                "s3:GetObjectVersionAcl",
                "s3:PutObjectTagging",
                "s3:DeleteObject",
                "s3:DeleteObjectTagging",
                "s3:GetBucketPolicyStatus",
                "s3:GetObjectRetention",
                "s3:GetBucketWebsite",
                "s3:PutReplicationConfiguration",
                "s3:GetObjectAttributes",
                "s3:DeleteObjectVersionTagging",
                "s3:PutObjectLegalHold",
                "s3:InitiateReplication",
                "s3:GetObjectLegalHold",
                "s3:GetBucketNotification",
                "s3:PutBucketCORS",
                "s3:GetReplicationConfiguration",
                "s3:ListMultipartUploadParts",
                "s3:PutObject",
                "s3:GetObject",
                "s3:PutBucketNotification",
                "s3:PutBucketLogging",
                "s3:PutObjectVersionAcl",
                "s3:GetAnalyticsConfiguration",
                "s3:PutBucketObjectLockConfiguration",
                "s3:GetObjectVersionForReplication",
                "s3:GetLifecycleConfiguration",
                "s3:GetInventoryConfiguration",
                "s3:GetBucketTagging",
                "s3:PutAccelerateConfiguration",
                "s3:DeleteObjectVersion",
                "s3:GetBucketLogging",
                "s3:ListBucketVersions",
                "s3:ReplicateTags",
                "s3:RestoreObject",
                "s3:ListBucket",
                "s3:GetAccelerateConfiguration",
                "s3:GetObjectVersionAttributes",
                "s3:GetBucketPolicy",
                "s3:PutEncryptionConfiguration",
                "s3:GetEncryptionConfiguration",
                "s3:GetObjectVersionTorrent",
                "s3:AbortMultipartUpload",
                "s3:PutBucketTagging",
                "s3:GetBucketRequestPayment",
                "s3:GetObjectTagging",
                "s3:GetMetricsConfiguration",
                "s3:GetBucketOwnershipControls",
                "s3:DeleteBucket",
                "s3:PutBucketVersioning",
                "s3:PutObjectAcl",
                "s3:GetBucketPublicAccessBlock",
                "s3:ListBucketMultipartUploads",
                "s3:PutIntelligentTieringConfiguration",
                "s3:PutMetricsConfiguration",
                "s3:PutBucketOwnershipControls",
                "s3:PutObjectVersionTagging",
                "s3:GetBucketVersioning",
                "s3:GetBucketAcl",
                "s3:PutInventoryConfiguration",
                "s3:GetObjectTorrent",
                "s3:PutBucketWebsite",
                "s3:PutBucketRequestPayment",
                "s3:PutObjectRetention",
                "s3:GetBucketCORS",
                "s3:GetBucketLocation",
                "s3:ReplicateDelete",
                "s3:GetObjectVersion"
            ],
            "Resource": [
                "arn:aws:s3:::texpert-test-cache",
                "arn:aws:s3:::texpert-test-store",
                "arn:aws:s3:::texpert-test-store/*",
                "arn:aws:s3:::texpert-test-cache/*"
            ]
        }
    ]
}

License

This AWS Lambda function is licensed under Apache 2.0.