rano/config/config.go

package config

import (
	"fmt"
	"os"
	"path/filepath"
	"reflect"
	"strconv"
	"strings"

	"gitserver.in/patialtech/rano/config/dotenv"
	"gitserver.in/patialtech/rano/pkg/logger"
)

const (
	// projDir need to be same as project code root dir name
	projDir  = "rano"
	EnvDev   = "development"
	EnvProd  = "production"
	EnvStage = "staging"

	AuthUserCtxKey = "AuthUser"
)

var (
	conf   *Config
	AppEnv Env = EnvDev
)

type (
	Env    string
	Config struct {
		WebPort   int    `env:"WEB_PORT"`
		WebURL    string `env:"WEB_URL"`
		GraphPort int    `env:"GRAPH_PORT"`
		GrapURL   string `env:"GRAPH_URL"`
		DbURL     string `env:"DB_URL"`
	}
)

func init() {
	wd, _ := os.Getwd()

	// In dev env we run test and other program for diff dir locations under project root,
	// this makes reading env file harder.
	// Let's add a hack to make sure we fallback to root dir in dev env
	if AppEnv == EnvDev {
		idx := strings.Index(wd, projDir)
		if idx > -1 {
			wd = filepath.Join(wd[:idx], projDir)
		}
	}

	envVar, err := dotenv.Read(wd, fmt.Sprintf(".env.%s", AppEnv))
	if err != nil {
		panic(err)
	}

	conf = &Config{}
	conf.loadEnv(envVar)
}

// Read config for Env
func Read() *Config {
	if conf == nil {
		panic("config not initialized")
	}

	return conf
}

func (c *Config) loadEnv(vars map[string]string) {
	if c == nil {
		return
	}

	val := reflect.Indirect(reflect.ValueOf(c))
	for i := 0; i < val.NumField(); i++ {
		f := val.Type().Field(i)
		tag := f.Tag.Get("env")
		if tag == "" {
			continue
		}

		v, found := vars[tag]
		if !found {
			logger.Warn("var %q not found in file .env.%s", tag, AppEnv)
			continue
		}

		field := val.FieldByName(f.Name)
		if !field.IsValid() {
			continue
		}

		switch f.Type.Kind() {
		case reflect.Int:
			if intV, err := strconv.ParseInt(v, 10, 64); err != nil {
				panic(err)
			} else {
				field.SetInt(intV)
			}
		default:
			field.SetString(v)
		}
	}

}