AWS API Gateway Setup

This is less for everyone else, but more for me to write down how I’ve set this up.

I’ve recently setup an API Gateway at https://api.andrewnorman.uk where I can host random APIs. The API Gateway Web UI makes it pretty easy. After setting up route 53 (not going to cover that here), and setting up a certificate (also won’t cover that here) you can add a custom domain name for your API gateway by clicking ‘Custom domain name’ and going through the steps. Once done, you’ll need to add API mappings. These map from your domain to an API Gateway app. A gateway app can either be setup on the root path, or on a sub path. I’ve set mine up on the root path, and I’ll deploy the entire application each time. But each immediate sub path I can setup with a different backing lambda. For instance, I’ve setup a health check as a separate lambda. The ‘/health’ endpoint is mapped in my project to that lambda.

To setup the project, I used the SAM CLI. Just run sam init to setup a sample project. To deploy the demo app, run sam build, and sam deploy --guided.

Running multiple lambdas can be setup in the template.yaml file. Set them up under the Resources key.

Resources:
  HeadlinePuzzleEncryptor:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: HeadlinePuzzleEncryptor
      Handler: uk.andrewnorman.headlinepuzzle.App::handleRequest
      Runtime: java8
      MemorySize: 512
      Events:
        HeadlinePuzzleEncrypt:
          Type: Api
          Properties:
            Path: /headline-puzzle/encrypt
            Method: post
  SomeOtherThing:
    ...

Then just create a project folder in the same path as the template file that matches your resource name (so HeadlinePuzzleEncryptor in this example). Throw in the appropriate build files (I use gradle), and setup a handler to handle the request.

I assume that it’s possible to run different runtimes all in the same API gateway. But I haven’t tested this yet. In the above, the URL this will map to is api.andrewnorman.uk/headline-puzzle/encrypt. If you were to map the gateway API to a path, that would sit inbetween andrewnorman.uk and /headline-puzzle.

As you can see, I’ve setup an encryptor API for the headline puzzle I was talking about the other week. I’ll add a blog page on that soon.