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 (13 chapters)

Exposing data operations over HTTP


Now that we have built all of our entities and the data access methods that operate on them, it's time to wire them up to an HTTP API. This will feel more familiar as we have already done this kind of thing a few times in the book.

Optional features with type assertions

When you use interface types in Go, you can perform type assertions to see whether the objects implement other interfaces, and since you can write interfaces inline, it is possible to very easily find out whether an object implements a specific function.

If v is interface{}, we can see whether it has the OK method using this pattern:

if obj, ok := v.(interface{ OK() error }); ok { 
  // v has OK() method 
} else { 
  // v does not have OK() method 
} 

If the v object implements the method described in the interface, ok will be true and obj will be an object on which the OK method can be called. Otherwise, ok will be false.

Note

One problem with this approach is that it hides the secret functionality...