Go env defaults

https://stackoverflow.com/questions/40326540/how-to-assign-default-value-if-env-var-is-empty

https://dev.to/craicoverflow/a-no-nonsense-guide-to-environment-variables-in-go-a2f

package config

import (
    "os"
    "strconv"
    "strings"
)

type GitHubConfig struct {
    Username string
    APIKey   string
}

type Config struct {
    GitHub    GitHubConfig
    DebugMode bool
    UserRoles []string
    MaxUsers  int
}

// New returns a new Config struct
func New() *Config {
    return &Config{
    GitHub: GitHubConfig{
        Username: getEnv("GITHUB_USERNAME", ""),
        APIKey:   getEnv("GITHUB_API_KEY", ""),
    },
    DebugMode: getEnvAsBool("DEBUG_MODE", true),
    UserRoles: getEnvAsSlice("USER_ROLES", []string{"admin"}, ","),
    MaxUsers:  getEnvAsInt("MAX_USERS", 1),
    }
}

// Simple helper function to read an environment or return a default value
func getEnv(key string, defaultVal string) string {
    if value, exists := os.LookupEnv(key); exists {
    return value
    }

    return defaultVal
}

// Simple helper function to read an environment variable into integer or return a default value
func getEnvAsInt(name string, defaultVal int) int {
    valueStr := getEnv(name, "")
    if value, err := strconv.Atoi(valueStr); err == nil {
    return value
    }

    return defaultVal
}

// Helper to read an environment variable into a bool or return default value
func getEnvAsBool(name string, defaultVal bool) bool {
    valStr := getEnv(name, "")
    if val, err := strconv.ParseBool(valStr); err == nil {
    return val
    }

    return defaultVal
}

// Helper to read an environment variable into a string slice or return default value
func getEnvAsSlice(name string, defaultVal []string, sep string) []string {
    valStr := getEnv(name, "")

    if valStr == "" {
    return defaultVal
    }

    val := strings.Split(valStr, sep)

    return val
}