Pros of godotenv

• Allows loading environment variables from a .env file, which is useful for development and testing
• Supports multiple .env files and overriding existing environment variables
• Simple and straightforward API for loading and parsing .env files

Cons of godotenv

• Focuses primarily on loading variables from files, not on parsing or type conversion
• Doesn't provide struct tag-based configuration like envconfig
• May require additional code for type conversion and validation

Code Comparison

godotenv:

err := godotenv.Load()
if err != nil {
    log.Fatal("Error loading .env file")
}
s3Bucket := os.Getenv("S3_BUCKET")

envconfig:

type Config struct {
    S3Bucket string `envconfig:"S3_BUCKET"`
}
var c Config
err := envconfig.Process("myapp", &c)

Summary

godotenv is ideal for projects that need to load environment variables from files, especially during development. It's simple to use but requires manual handling of variable types. envconfig, on the other hand, provides more robust parsing and type conversion capabilities, making it suitable for applications with complex configuration needs. The choice between the two depends on the specific requirements of your project and your preferred approach to configuration management.

Pros of Viper

• Supports multiple configuration sources (environment variables, config files, command-line flags)
• Offers live watching and automatic reloading of configuration files
• Provides a rich set of features like setting defaults, aliases, and type-safe settings

Cons of Viper

• More complex setup and usage compared to Envconfig's simplicity
• Larger codebase and dependencies, potentially increasing build size
• May be overkill for simple projects that only need environment variable configuration

Code Comparison

Envconfig:

type Config struct {
    Host string `envconfig:"HOST"`
    Port int    `envconfig:"PORT"`
}

var c Config
err := envconfig.Process("myapp", &c)

Viper:

viper.SetEnvPrefix("myapp")
viper.AutomaticEnv()
viper.SetConfigName("config")
viper.AddConfigPath(".")
err := viper.ReadInConfig()

host := viper.GetString("host")
port := viper.GetInt("port")

Envconfig focuses solely on environment variables with a straightforward struct-based approach, while Viper offers a more flexible and feature-rich configuration management system at the cost of increased complexity.

Pros of env

• Supports parsing of slices, maps, and time.Duration
• Offers custom parsers for more complex types
• Provides options for prefix stripping and environment variable name customization

Cons of env

• Slightly more complex API compared to envconfig
• May require more setup for advanced use cases
• Less widespread adoption in the Go community

Code Comparison

envconfig:

type Config struct {
    Port int `envconfig:"PORT"`
    Debug bool `envconfig:"DEBUG"`
}

var c Config
err := envconfig.Process("myapp", &c)

env:

type Config struct {
    Port int `env:"PORT"`
    Debug bool `env:"DEBUG"`
}

var c Config
err := env.Parse(&c)

Summary

Both envconfig and env are popular libraries for parsing environment variables in Go applications. envconfig is known for its simplicity and widespread adoption, while env offers more advanced features like custom parsers and support for complex types. The choice between the two depends on the specific requirements of your project and the level of customization needed for environment variable parsing.

Pros of cleanenv

• Supports multiple configuration sources (environment variables, config files, flags)
• Offers built-in validation and custom validation functions
• Provides a more feature-rich and flexible configuration solution

Cons of cleanenv

• May have a steeper learning curve due to additional features
• Potentially higher overhead for simple use cases
• Less established and battle-tested compared to envconfig

Code Comparison

envconfig:

type Config struct {
    Port int `envconfig:"PORT"`
    Debug bool `envconfig:"DEBUG"`
}

var c Config
err := envconfig.Process("myapp", &c)

cleanenv:

type Config struct {
    Port int `env:"PORT" env-default:"8080"`
    Debug bool `env:"DEBUG" env-default:"false"`
}

var c Config
err := cleanenv.ReadEnv(&c)

Both libraries offer similar basic functionality for reading environment variables into struct fields. However, cleanenv provides additional features like default values and supports multiple configuration sources.

cleanenv is more versatile and feature-rich, making it suitable for complex configuration scenarios. envconfig, on the other hand, is simpler and more focused on environment variables, which may be preferable for straightforward use cases or when minimal dependencies are desired.

The choice between the two depends on the specific requirements of your project, such as the need for multiple configuration sources, validation, or simplicity.

Pros of koanf

• Supports multiple configuration sources (environment variables, files, command-line flags)
• Offers advanced features like type conversion, default values, and nested structures
• Provides a more flexible and extensible configuration management system

Cons of koanf

• More complex setup and usage compared to envconfig's simplicity
• Steeper learning curve due to its extensive feature set
• Potentially overkill for small projects with simple configuration needs

Code Comparison

envconfig:

type Config struct {
    Host string `envconfig:"HOST"`
    Port int    `envconfig:"PORT"`
}

var cfg Config
err := envconfig.Process("myapp", &cfg)

koanf:

var k = koanf.New(".")
k.Load(file.Provider("config.yaml"), yaml.Parser())
k.Load(env.Provider("MYAPP_", ".", func(s string) string {
    return strings.Replace(strings.ToLower(s), "_", ".", -1)
}), nil)

var cfg Config
err := k.Unmarshal("", &cfg)

The code comparison demonstrates that envconfig is more straightforward for simple environment variable parsing, while koanf offers more flexibility in configuration sources and parsing options. koanf requires more setup but provides greater control over the configuration process.