API Backend on AWS Lambda

Question

Context: I have a usecase where my backend service should compute 1 or more features, where each feature is a simple peace of computation (can be as simple as adding two numbers) and each feature takes input and return an output value, which can be boolean or a number. Client can actually request features (1 or 10 etc), also each feature can have multiple versions.

Design: Lambda function seems like a good choice, since it supports versioning and takes care of scaling. In my design, one Lambda will receive the request and then call further lambda functions in parallel (Say user asked for 12 features, Lambda function L1 will invoke 12 Lambda functions in parallel) synchronously, and return all computed feature values as one response (HTTP). This way, all features can be versioned in their own Lambda functions.

Questions: Is it ok to call a lambda function directly from another Lambda function? Is it a good usecase for using Lambda functions?

Thanks

Answer 1

I think Lambda would work just fine for your use case. For versioning, you could use the API versioning provided by API Gateway but I think that is a bit much for your case. Just create different functions.

Check out serverless.com. It is a solid framework and easy to get started with. It will take a lot of the work out of setting it up, plus you'll have your infrastructure as code.

Yes, it is okay to call lambdas from other Lambdas. There is not a 'clean' way to do that though. On the other hand, 'Step functions' may be what you need. Lambda support's chaining functions in a workflow. The previous lambda is not 'calling' the next function as much as proceeding to the next step in the workflow. The Serverless framework also supports using the method and can be configured in the serverless.yml config file