Written by the team that helped bring the Swift language to Cloud computing, this is THE definitive guide to writing and running Swift. We'll cover all aspects of creating and running Swift language applications, complete with real code examples that you can start running and experimenting with today.

Swift in the Cloud

Preface

On December 3, 2015, Apple made version 2.2 of the Swift programming language open source software by creating Swift.org and contributing a key set of source code repositories covering the compilers, debuggers, libraries, and more. The Swift.org site ( https://swift.org ) was set up to serve as a central hub for this new community. The site contains documentation, binary downloads, links to the open source repositories on GitHub, mailing lists, and bug reporting mechanisms, as well as continuous integration support to maintain stability across the projects. In this chapter, I will cover what is included on the site as well as some pointers about how to get involved in this exciting community.

Swift.org, the Open Source Project

When Apple made the Swift language open source on Swift.org , they also made available an Ubuntu Linux version of the language for binary download. IBM responded by announcing the IBM Swift Sandbox ( https://swift.sandbox.bluemix.net ), which is a website that developers can visit to write Swift code in a web-based code editor. When they are ready, the developers can click the run button and their code is compiled and runs on a fresh Linux container in the IBM Bluemix Cloud.

A Swift Sandbox in the Cloud

A number of resources are available for learning to program with Swift. While the focus of this book is primarily on the tools, libraries, and runtimes needed to create Swift applications on the server, this chapter will start off with a background and overview of the Swift language.

A Basic Introduction to Swift

Bluemix supports Cloud Foundry (http://docs.cloudfoundry.org), which is a popular open source Platform as a service (PaaS) for creating and deploying applications on the Cloud. Because of this, as a developer on Bluemix, you have access to artifacts and resources that are first-class citizens in the Cloud Foundry platform, such as buildpacks.

The IBM Bluemix Buildpack for Swift

The IBM Bluemix Container Service brings Docker and Kubernetes together for enabling rapid delivery of applications. Using Docker, developers can easily include all the components and dependencies an application requires to execute. If you are familiar with Docker, then you have probably seen the benefits it provides, such as portability and resource isolation. Kubernetes is an open source platform for managing containerized applications and, among other tasks, for facilitating self-healing actions in case of errors.

Using Containers on Bluemix to Run Swift Code

Every large software project has unique requirements and challenges. As a developer, you want to focus your attention on the problems that haven’t been solved before. Common, repeatable aspects of your solution can be addressed by third-party components and libraries. You may also find that your project is well suited to contribute its own components to be reused by others.

Swift Package Management

Modern user-facing applications are typically built as two separate parts, a front end and a back end. This is especially true in the enterprise application space. This separation of the front end and back end enables user-facing applications to offer great user experiences and user interfaces, while enforcing enterprise and legal requirements in the server. This also enables multiple front ends, such as mobile apps and web applications with the same back end.

Swift and Kitura for Web Applications

In previous chapters of this book, you’ve read about Swift being used to implement cloud-hosted services that fit typical traditional server-side functions, such as web applications and data sources. However, there are some newer programming models that have arisen in cloud computing environments that offer distinct benefits for certain workloads. Swift also supports these models, and this chapter covers how the Swift language is used in one of these cloud environments—namely event-driven, or serverless, environments.

Serverless Programming with Swift

Even though this book was written just two years after the initial release of Swift, this language has made very rapid progress in that short time. It has established a firm beachhead as a client-side language for the Apple ecosystem, and it has contributed to improved quality of developer’s code as well as faster development cycles. Swift has gone from a proprietary language to a fully transparent open source project with a very large and active community supporting its evolution. The 3.0 release of Swift also delivered an initial level of support for the language to be used for server-side (and cloud) software. So now the question is, where do we go from here?

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