Image Resize service

Services:

• Lambda function
• API Gateway

This service requires an S3 Bucket as a source of images, set as Static Hosting, with the following

bucket policy:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "AddPerm",
            "Effect": "Allow",
            "Principal": "*",
            "Action": "s3:GetObject",
            "Resource": "arn:aws:s3:::BUCKET_NAME/*"
        }
    ]
}

redirect rule:

<RoutingRules>
  <RoutingRule>
    <Condition>
      <KeyPrefixEquals/>
      <HttpErrorCodeReturnedEquals>404</HttpErrorCodeReturnedEquals>
    </Condition>
    <Redirect>
      <Protocol>https</Protocol>
      <HostName>API_GATEWAY_HOSTNAME</HostName>
      <ReplaceKeyPrefixWith>prod/resize?key=</ReplaceKeyPrefixWith>
      <HttpRedirectCode>307</HttpRedirectCode>
    </Redirect>
  </RoutingRule>
</RoutingRules>

ENV variables for BUCKET_NAME and URL are currently saved in the function-template.yaml

---

The image is requested in the folder on S3 that contains the resized copy like:

path-to-image/s200x100/image.[jpg|webp]

The original image must be in the parent folder like:

path-to-image/image.jpg

--

The 'resize' folder can have the following pattern:

• s200x100 (resize and crop with provided width and height)
• w200 (resize to provided width, keep ratio)
• h200 (resize to provided height, keep ratio)

--

Provess:

The file is requested to S3, when that size is not available the request gets redirected to the API gateway which fires the lambda function associated to perform the resize/crop/format on the original image.

If a WEBP format is requested, the file will be generated always from the original JPG version and saved for further requests.

Then the new file is saved in the correct folder into the S3 bucket itself and returned to the user.

---

TODO:

• Complete the docs including the process to package/deploy the stack
• Build a pipeline to CI/CD