Book Image

.Go Programming Blueprints - Second Edition

By : Mat Ryer
Book Image

.Go Programming Blueprints - Second Edition

By: Mat Ryer

Overview of this book

Go is the language of the Internet age, and the latest version of Go comes with major architectural changes. Implementation of the language, runtime, and libraries has changed significantly. The compiler and runtime are now written entirely in Go. The garbage collector is now concurrent and provides dramatically lower pause times by running in parallel with other Go routines when possible. This book will show you how to leverage all the latest features and much more. This book shows you how to build powerful systems and drops you into real-world situations. You will learn to develop high quality command-line tools that utilize the powerful shell capabilities and perform well using Go's in-built concurrency mechanisms. Scale, performance, and high availability lie at the heart of our projects, and the lessons learned throughout this book will arm you with everything you need to build world-class solutions. You will get a feel for app deployment using Docker and Google App Engine. Each project could form the basis of a start-up, which means they are directly applicable to modern software markets.
Table of Contents (19 chapters)
Go Programming Blueprints Second Edition
Credits
About the Author
Acknowledgments
About the Reviewer
www.PacktPub.com
Preface

Summary


In this chapter, we developed a complete concurrent chat application and our own simple package to trace the flow of our programs to help us better understand what is going on under the hood.

We used the net/http package to quickly build what turned out to be a very powerful concurrent HTTP web server. In one particular case, we then upgraded the connection to open a web socket between the client and server. This means that we can easily and quickly communicate messages to the user's web browser without having to write messy polling code. We explored how templates are useful to separate the code from the content as well as to allow us to inject data into our template source, which let us make the host address configurable. Command-line flags helped us give simple configuration control to the people hosting our application while also letting us specify sensible defaults.

Our chat application made use of Go's powerful concurrency capabilities that allowed us to write clear threaded code in just a few lines of idiomatic Go. By controlling the coming and going of clients through channels, we were able to set synchronization points in our code that prevented us from corrupting memory by attempting to modify the same objects at the same time.

We learned how interfaces such as http.Handler and our own trace.Tracer interface allow us to provide disparate implementations without having to touch the code that makes use of them, and in some cases, without having to expose even the name of the implementation to our users. We saw how just by adding a ServeHTTP method to our room type, we turned our custom room concept into a valid HTTP handler object, which managed our web socket connections.

We aren't actually very far away from being able to properly release our application, except for one major oversight: you cannot see who sent each message. We have no concept of users or even usernames, and for a real chat application, this is not acceptable.

In the next chapter, we will add the names of the people responding to their messages in order to make them feel like they are having a real conversation with other humans.