Simplify Configuration Management in Golang with Viper

Managing configuration in a Golang project can often be a challenging task, especially when dealing with multiple environment variables. The viper package offers a simple and effective solution for loading and managing these variables. In this post, we’ll walk through how to use viper to load .env variables in your Golang application.

Setting Up Viper

First, you need to install the viper package. You can do this using go get:

go get github.com/spf13/viper

Loading Configuration

Let’s create a configuration file to load environment variables. Here’s an example of how you can structure your code:

package configs

import (
    "log"
    "github.com/spf13/viper"
)

// Env holds the environment variables
type Env struct {
    Port          string `mapstructure:"PORT"`
    MongoURL      string `mapstructure:"MONGO_URI"`
    RedisURL      string `mapstructure:"REDIS_URI"`
    SecretToken   string `mapstructure:"SECRET_TOKEN"`
    RefreshToken  string `mapstructure:"REFRESH_TOKEN"`
}

// LoadConfig reads and loads the environment variables from a .env file
func LoadConfig() *Env {
    var envs Env

    viper.AddConfigPath(".")
    viper.SetConfigName(".env")
    viper.SetConfigType("env")
    
    if err := viper.ReadInConfig(); err != nil {
        log.Fatalf("Error reading config file, %s", err)
    }

    if err := viper.Unmarshal(&envs); err != nil {
        log.Fatalf("Unable to decode into struct, %v", err)
    }

    return &envs
}

In this code:

• We define an Env struct to map our environment variables.
• The LoadConfig function reads the .env file, loads the environment variables using viper, and unmarshals them into the Env struct.

Using the Configuration

You can now use the LoadConfig function to load your environment variables at the start of your application:

package main

import (
    "fmt"
    "myapp/configs"
)

func main() {
    envs := configs.LoadConfig()
    fmt.Printf("Port: %s\n", envs.Port)
    fmt.Printf("MongoURL: %s\n", envs.MongoURL)
    fmt.Printf("RedisURL: %s\n", envs.RedisURL)
    fmt.Printf("SecretToken: %s\n", envs.SecretToken)
    fmt.Printf("RefreshToken: %s\n", envs.RefreshToken)
}

Conclusion

Using viper to manage environment variables in Golang is an efficient way to handle configuration. It simplifies the process of loading variables and ensures your application is easy to configure and maintain. Give it a try in your next Golang project and enjoy a more streamlined configuration management process!

Happy coding!

This blog post explains how to use viper to load environment variables in Golang, providing clear examples and explanations to help you get started.