This package just makes it simpler to deal with configuration. Just define a struct with the appropriate tags, and either embed the config.Config struct type or manually implement the interface (I recommend the former), and then you're essentially good to go. Observe:

package main
import (
    "time"
    "github.com/santiclause/goconfig"
)
type Config struct {
	HttpPort            int           `yaml:"http_port" env:"HTTP_PORT"`
	ConnTimeout         time.Duration `yaml:"conn_timeout" env:"CONN_TIMEOUT" required:"true"`
	RequestGracePeriod  time.Duration `yaml:"request_grace_period" env:"REQUEST_GRACE_PERIOD"`
	goconfig.Config
}

func main() {
    // Make the struct, with a default value (since Load will overwrite it)
    config := &Config{
        HttpPort: 8080,
    }
    config.SetFilename("whatever.yaml")
    goconfig.Load(config)
    // Optionally make it listen for SIGHUPs
    goconfig.ListenForSignals(config)
}

• env: see https://github.com/caarlos0/env
• yaml: see https://github.com/go-yaml/yaml
• required: if this has a value of "true", Load will return an error if that struct field has a zero value after parsing the yaml and environment variables.

The provided yaml file will be loaded first (if it exists), and environment variables will override the yaml files.

The Config struct type also defines a debug level and reads it from yaml: debug and env: DEBUG respectively, and you can check if the debug level is at least at a certain level via config.DebugLevel(level) - e.g.:

if config.DebugLevel("info") {
    log.Println("New connection from client")
}