AWS

tip

Don't know what a handler is? See the Architecture section.

This is a serverless handler implementation that will return a function that expect to receive the following arguments: event, context and callback, respectively.

function(event, context, callback) {...}

If your cloud's serverless handler signature is the same, you can use this handler.

This is usually enough to add support for clouds like: AWS, Huawei and others.

Usage

To use, you can import and call the method setHandler, as per the code below:

index.ts

import { ServerlessAdapter } from '@h4ad/serverless-adapter';
import { DefaultHandler } from '@h4ad/serverless-adapter/handlers/default';
import app from './app';

export const handler = ServerlessAdapter.new(app)
  .setHandler(new DefaultHandler())
  // continue to set the other options here.
  //.setResolver(new PromiseResolver())
  //.setFramework(new ExpressFramework())
  //.addAdapter(new AlbAdapter())
  //.addAdapter(new SQSAdapter())
  //.addAdapter(new SNSAdapter())
  // after put all methods necessary, just call the build method.
  .build();

AWS Lambda Response Streaming

info

This handler is intended to be used when you integrate with FunctionURLs, which is the only service that supports streaming on AWS currently, read more.

By default, every Lambda will be BUFFERED, which means we need to wait for the framework to write all the content of the response until we send it to the user.

But when you enable the RESPONSE_STREAM mode within your Lambda settings, the framework will send the response to the user as fast as possible, without waiting for the framework to write all the content.

To support this behavior, we need to change three things:

• Instead of DefaultHandler, you should use AwsStreamHandler.
• Instead of PromiseResolver or whatever, you should use DummyResolver.
  • Resolvers are not used in this mode, so you can just use this dummy version.
• Add the adapter ApiGatewayV2Adapter.
  • It is required to handle function URLs, but you can add more if you wish.

index.ts

import { ServerlessAdapter } from '@h4ad/serverless-adapter';
import { AwsStreamHandler } from '@h4ad/serverless-adapter/handlers/aws';
import { DummyResolver } from '@h4ad/serverless-adapter/resolvers/dummy';
import { ApiGatewayV2Adapter } from '@h4ad/serverless-adapter/adapters/aws';
import app from './app';

export const handler = ServerlessAdapter.new(app)
  .setHandler(new AwsStreamHandler())
  .setResolver(new DummyResolver())
  .setAdapter(new ApiGatewayV2Adapter())
  // continue to set the other options here.
  //.addAdapter(new AlbAdapter())
  //.addAdapter(new SQSAdapter())
  //.addAdapter(new SNSAdapter())
  //.setFramework(new ExpressFramework())
  // after put all methods necessary, just call the build method.
  .build();

As you see, we only have to change the setHandler, setResolver and setAdapter methods, that's all!

My execution is taking too long

Well, maybe is caused because your event loop is not empty when the request finishes, in this case, you can set callbackWaitsForEmptyEventLoop=false on AwsStreamHandler.

index.ts

import { ServerlessAdapter } from '@h4ad/serverless-adapter';
import { AwsStreamHandler } from '@h4ad/serverless-adapter/handlers/aws';
import { DummyResolver } from '@h4ad/serverless-adapter/resolvers/dummy';
import { ApiGatewayV2Adapter } from '@h4ad/serverless-adapter/adapters/aws';
import app from './app';

export const handler = ServerlessAdapter.new(app)
  .setHandler(new AwsStreamHandler({ callbackWaitsForEmptyEventLoop: false }))
  .setResolver(new DummyResolver())
  .setAdapter(new ApiGatewayV2Adapter())
  // continue to set the other options here.
  //.addAdapter(new AlbAdapter())
  //.addAdapter(new SQSAdapter())
  //.addAdapter(new SNSAdapter())
  //.setFramework(new ExpressFramework())
  // after put all methods necessary, just call the build method.
  .build();

Can I use SQS and other services?

Well, I don't know, but you can try. At least with SQS I was able to get the messages, but I couldn't use the partial batch response feature.

Other services may or may not work, at least if it's a service that doesn't need a response, maybe it works now.

Examples

You can see examples of how to use here.