This repository contains a set of services and a command line app that demonstrate features of the go language. You'll find references below on where different features of go are being used. You'll also find descriptions of the design/architectural patterns that are in use. Please see the READMEs in the apps, services, and frameworks directories for descriptions of their functionality.

Structs are everywhere in this reference repository. Just search for struct and you'll find tons of examples. Structs are go's classes or the closest we'll get to a class. It's important to remember that the functions and attributes connected to a struct that start with a lower-case letter are private (not exported in go terminology) and those that start with a Upper-case letter are exported (you can think of them as public :) ). This is really important when using the JSON libraries to Marshal/Unmarshal structs. Only exported attributes are converted. There are workarounds. Take a look at apps/models/user.go for an example.

Custom types can be super powerful in go. They allow you to build some business rules into types that are validated at compile time. That's way before a user sees your code and that's a good thing. The logging framework has the best example. Take a look at fameworks/log/logger.go and the Level type for an example.

Routines in go provide the ability to execute in parallel or on multiple threads. The only rudimentary example of this in this repository is in apps/cli/app.go. The RunAsync function will run each Processor in it's own thread asyncrhonously.

The most valuable or interesting test-relate example in this repository are the mocks. In each of the frameworks subdirectories you'll find mocks.go file with a mock for the various interfaces. I wish I could remember who to give credit for this concept. I found it in some tutorial. The mock's implement the interface and have two key parts: An invoked flag, that will tell you if the method was called, and a func that allows each test to do something unique when each method is called.

The only other note for now is in the test themseleves. I've used the VS Code extension for go's test generator in almost every test. For the most part I've removed teh generated args attribute. I just don't get it. I've also changed the format of the reported error to include the test name.

Since go doesn't have the concept of a constructor for structs, you'll find the use of struct/class factories all over go code. This usually takes the form of a function called NewStructName(). You can find many examples of this patter in this repository.

More elobarate examples of factories that generate interfaces based on configuration data can be found in frameworks/log/logger.go and frameworks/storage/store.go. Each of these new functions will generate an implementation of the interface based on configurator settings.

One of the interesting uses of factories or constructors in general, is the abilty to create contextually aware code. That is, when a struct or interface is created with a factory or constructor you can set there defaults intelligently. frameworks/service/http.go for example will create the HTTPServicer with a default port of 8080 unless there is a port defined in the configurator. You can imagine this pattern being used to have a base default if nothing is set, or if in a dev environment the setting could come from a .env file and in a production environment the setting could come from a configuration service.

Inheritance is not a built in go construct. The concept of inheritance (inheriting behavior of a parent class and chosing to use it or extend it) is easily achievable. If two structs implement the same interface, one can become a base/parent/super class of the other by simply adding it to the child struct. You can find an examples of this patern in this repository.

The Configurator interface. frameworks/config/dotenv.go implements the Configurator interface and uses frameworks/config/base.go as it's "parent" or super class. The reference in dotenv to base is called super but that's just to make old school OO developers happy. There's nothing special about the attribute name "super".