Powerful Command-Line Applications in Go/

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Using Viper for Configuration Management

Learn how to use Viper for configuration management in our application.

We'll cover the following...

Defining the initConfig() function
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When we use the Cobra generator to create the boilerplate code for our application, it automatically enables Viper. Viper is a configuration management solution for Go applications that allows us to specify configuration options for our application in several ways, including configuration files, environment variables, and command-line flags.

Defining the `initConfig()` function

Cobra enables Viper by running the function initConfig() when initializing the application. This function is defined in the cmd/root.go file:

func initConfig() {
  if cfgFile != "" {
    // Use config file from the flag.
    viper.SetConfigFile(cfgFile)
  } else {
    // Find home directory.
    home, err := homedir.Dir()
    if err != nil {
      fmt.Println(err)
      os.Exit(1)
    }
    // Search config in home directory with name ".pScan" (without extension).
    viper.AddConfigPath(home)
    viper.SetConfigName(".pScan")
  }
  viper.AutomaticEnv() // read in environment variables that match
  // If a config file is found, read it in.
  if err := viper.ReadInConfig(); err == nil {
    fmt.Println("Using config file:", viper.ConfigFileUsed())
  }
}

Defining the initConfig() function

Introduction

First Command-Line Program in Go

Interacting with Users

Working with Files in Go

Navigating the File System

Improving the Performance of CLI Tools

Controlling Processes

Using the Cobra CLI Framework

Talking to REST API

Developing Interactive Terminal Tools

Persisting Data in a SQL Database

Distributing Tool

Appendix

Using Viper for Configuration Management

Defining the `initConfig()` function