Async HTTP API Lambda Layer

This is a lambda layer package that allows you to return data from your http API before your ASYNC_HANDLER has finished executing.

This allows you to perform fire and forget http APIs similar to the old X-Amz-Invocation-Type: Event that is enabled on v1 APIs.

How to use

This repository is basically an example repo showing how to deploy and integrate with this async handler.

Each function in the serverless.yml file presents a different way to interact with the layer.

• longRunning - This function demonstrates an ASYNC handler that runs way after a typical HTTP API would be required to return a response. It is also using the built in layer proxy handler that will take care of passing the event and context object to the async handler.
• customResponse - This function demonstrates an async handler that uses the built in layer proxy handler and customizes the response message.
• customHandler - This function demonstrates a custom handler paired with an ASYNC_HANDLER. This also demonstrates how to use the sendArgs method exposed by our layer.

Layer details

This layer includes an external extension that is monitoring for an http event from the internal lambda function that forwards the event and context information. It also includes a lambda handler you can use to send quick responses back to API gateway as well as a sendArgs method that allows you use a custom handler.

Once the event and context information is received the extension will then execute the ASYNC_HANDLER function supplied in our environment variables.

Environment variables

Name	Description	Required (Y/N)	Default
ASYNC_HANDLER	This is the path to your async handler. This is similar to the normal handler property in the function description in the serverless.yml file.	Y	N/A
CUSTOM_RES	If you want to use the built-in proxy handler but you would like to customize the http response you can do that via this variable. (Example on customResponse function 😉)	N	N/A