map-dots/traccar/config.go

package traccar

import (
	"errors"
	"os"
	"strings"
)

type cfgParam struct {
	EnvVarName   string
	ConfFilePath string
	DefaultValue string
	FailIfAbsent bool
}

type cfg struct {
	user string
	pass string
	tUrl string
}

func loadConfig() (*cfg, error) {
	cfgParams := map[string]cfgParam{
		"user": {
			EnvVarName:   "TRACCAR_USER",
			ConfFilePath: "/mapdots/cfg/traccar-user",
			FailIfAbsent: true,
		},
		"pass": {
			EnvVarName:   "TRACCAR_PASS",
			ConfFilePath: "/mapdots/cfg/traccar-pass",
			FailIfAbsent: true,
		},
		"tUrl": {
			EnvVarName:   "TRACCAR_URL",
			ConfFilePath: "/mapdots/cfg/traccar-url",
		},
	}

	cfg := &cfg{}

	for key, param := range cfgParams {
		if val, ok := os.LookupEnv(param.EnvVarName); ok {
			cfg.setConfigValue(key, string(val))
			continue
		}

		if data, err := os.ReadFile(param.ConfFilePath); err == nil {
			cfg.setConfigValue(key, string(data))
			continue
		}

		if param.DefaultValue != "" {
			cfg.setConfigValue(key, param.DefaultValue)
			continue
		}

		if param.FailIfAbsent {
			return nil, errors.New("Failed to load configuration: " + key + " is required but not set")
		}

	}

	return cfg, nil
}

func (c *cfg) setConfigValue(key, value string) {

	stripNewlines := func(s string) string {
		return strings.ReplaceAll(s, "\n", "")
	}

	switch key {
	case "user":
		c.user = stripNewlines(value)
	case "pass":
		c.pass = stripNewlines(value)
	case "tUrl":
		c.tUrl = stripNewlines(value)
	}
}