Vert.x is an awesome tool-kit for developing reactive microservices. In this article, I’m going to present an adapter that allows you to run your Vert.x web service as a Lambda function on AWS.

If you are creating web services using Vert.x, you are leveraging the HTTP server built into the core of the Vert.x tool-kit. This HTTP server is based on the Netty framework. When your web service comes up, the HTTP server opens a network port and starts listening for the incoming client connections. After a client connects, the HTTP server reads the HTTP request and processes this request by invoking callbacks that you registered. HTTP response generated by your implementation is returned back to the client. The web service remains running and processing requests until you shut it down.

In contrast to the constantly running web service, an AWS Lambda function is instantiated to serve a single HTTP request. After the HTTP request has been processed, the Lambda function is torn down.

In our company, we’re looking at deploying our web services on-premise and in the cloud. We realized that when deploying into AWS it would be more cost effective if we could run some of our web services as Lambda functions. The question was, how to allow a Vert.x web service to alternatively run as a Lambda function? And how to accomplish this with a minimum development and maintenance effort?

After browsing through the Vert.x source code, it occurred to me that it would be possible to write a simple adapter that would convert HTTP requests and responses between the Lambda API and the Vert.x API. I then get on with the job and implemented such an adapter. And because software practitioners love open source, you can find this adapter along with the sample application on GitHub: vertx-aws-lambda.

As always, I’d love to hear your feedback. What do you think about this project? Feel free to leave your comments below.