逐步加载由 Lambda function 生成的 AWS S3 文件

Question

I have a site where the user can upload an image. The image is uploaded to an S3 bucket, then processed with a Lambda function that generates 7 different coloured versions of the image, stores them on an S3 bucket and the function ultimately returns the URLs of the new coloured images back to the user so they can select their preferred color on the site.

This process takes some time, around 5-6 seconds with a good connection, during which the user can only see a loading screen. Since it's only possible with one callback from lambda, how would I go about to "lazy load" the 7 different coloured images rather than having the loading screen? I would like to have something like a skeleton UI which gradually loads the different coloured images as soon as each of them are generated, rather than having to wait for all of them. Is this possible?

Answer 1

A better approach might be to return the URLs immediately , before the images are actually generated, because the target URLs will be known. This could be done by having the Lambda function invoke another Lambda to do the actual processing, and then return the URL immediately.

Then, the web app could try to retrieve the images every few seconds.

You could even have the process spawn several Lambda processes in parallel to reduce the time taken to generate all the images (and/or try multi-threading the Lambda to see if that is any faster).