Book Image

Docker for Serverless Applications

By : Chanwit Kaewkasi
Book Image

Docker for Serverless Applications

By: Chanwit Kaewkasi

Overview of this book

Serverless applications have gained a lot of popularity among developers and are currently the buzzwords in the tech market. Docker and serverless are two terms that go hand-in-hand. This book will start by explaining serverless and Function-as-a-Service (FaaS) concepts, and why they are important. Then, it will introduce the concepts of containerization and how Docker fits into the Serverless ideology. It will explore the architectures and components of three major Docker-based FaaS platforms, how to deploy and how to use their CLI. Then, this book will discuss how to set up and operate a production-grade Docker cluster. We will cover all concepts of FaaS frameworks with practical use cases, followed by deploying and orchestrating these serverless systems using Docker. Finally, we will also explore advanced topics and prototypes for FaaS architectures in the last chapter. By the end of this book, you will be in a position to build and deploy your own FaaS platform using Docker.
Table of Contents (15 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Preparing a WebHook in Fn


The Fn Project works best with functions written in Java. When calling a function, the framework would be able to automatically transform the body of the request as a parameter of the entrypoint method. In the following example, the JSON from the request will be converted into a string for the handleRequest method, the entrypoint method of this Fn function:

public Object handleRequest(String body) {
    if (body == null || body.isEmpty()) {
        body = "{}";
    }
     Input input;
    try {
        val mapper = new ObjectMapper();
        input = mapper.readValue(body, Input.class);
    } catch (IOException e) {
        return new Error(e.getMessage());
    }
     if (input == null) {
        return new Error(body);
     }
     /* process the rest of business logic */
}

Here's the list of data transfer object (DTO) classes to properly encode and decode Parse's WebHook messages inside an Fn function. With help from Project Lombok and Jackson, we can dramatically...