DefaultConfig - Go Configuration Loader with Default Values

DefaultConfig is a library for loading YAML configuration files and mapping data into a struct in Golang, using Viper. It supports environment variables and default values.

🚀 Installation

Add the library to your project:

go get -u github.com/anhnmt/go-defaultconfig

🛠️ Usage

1️⃣ Define the Configuration Struct

type Config struct {
    Name  string `mapstructure:"name" default:"default_name"`
    Debug bool   `mapstructure:"debug" default:"false"`
}

2️⃣ Create a Configuration File (e.g., config/dev.yml)

name: "my_app"
debug: true

3️⃣ Load Configuration with Load

package main

import (
    "fmt"
    "log"
)

func main() {
    var cfg Config
    err := defaultconfig.Load("./config", "dev", &cfg)
    if err != nil {
        log.Fatalf("Error loading config: %v", err)
    }
    fmt.Printf("Loaded config: %+v\n", cfg)
}

🔧 Load Function Details

func Load(dir, env string, cfg any) error

✅ Parameters

• dir: Path to the directory containing the configuration files.
• env: Environment name (corresponding to config/{env}.yml).
• cfg: Pointer to the struct that receives the configuration data.

🔄 How It Works

1. Determines the configuration file path (config/{env}.yml).
2. Reads the YAML file and maps it into cfg.
3. Supports environment variables (converts . to _).
4. Supports default values from the struct tag default.

✅ Environment Variables Example

If environment variables are set:

export NAME="env_name"
export DEBUG=true

The program will use these values instead of those in the YAML file.

🧪 Running Unit Tests

# Run all tests
go test -v ./...

📜 License

MIT License