this seems okay

config/new.go

@@ -0,0 +1,114 @@
+package config
+
+import (
+	"flag"
+	"io/ioutil"
+	"local/rproxy3/storage"
+	"local/rproxy3/storage/packable"
+	"log"
+	"strings"
+
+	yaml "gopkg.in/yaml.v2"
+)
+
+const nsConf = "configuration"
+const flagPort = "p"
+const flagRoutes = "r"
+const flagConf = "c"
+const flagCert = "crt"
+const flagKey = "key"
+const flagUser = "user"
+const flagPass = "pass"
+
+var conf = storage.NewMap()
+
+type toBind struct {
+	flag  string
+	value *string
+}
+
+type fileConf struct {
+	Port     string   `yaml:"port"`
+	Routes   []string `yaml:"routes"`
+	CertPath string   `yaml:"cert"`
+	KeyPath  string   `yaml:"key"`
+	Username string   `yaml:"user"`
+	Password string   `yaml:"pass"`
+}
+
+func Init() error {
+	log.SetFlags(log.Ldate | log.Ltime | log.Llongfile)
+	if err := fromFile(); err != nil {
+		return err
+	}
+	if err := fromFlags(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func fromFile() error {
+	flag.String(flagConf, "/dev/null", "yaml config file path")
+	confFlag := flag.Lookup(flagConf)
+	if confFlag == nil || confFlag.Value.String() == "" {
+		return nil
+	}
+	confBytes, err := ioutil.ReadFile(confFlag.Value.String())
+	if err != nil {
+		return err
+	}
+	var c fileConf
+	if err := yaml.Unmarshal(confBytes, &c); err != nil {
+		return err
+	}
+	if err := conf.Set(nsConf, flagPort, packable.NewString(c.Port)); err != nil {
+		return err
+	}
+	if err := conf.Set(nsConf, flagRoutes, packable.NewString(strings.Join(c.Routes, ","))); err != nil {
+		return err
+	}
+	if err := conf.Set(nsConf, flagCert, packable.NewString(c.CertPath)); err != nil {
+		return err
+	}
+	if err := conf.Set(nsConf, flagKey, packable.NewString(c.KeyPath)); err != nil {
+		return err
+	}
+	if err := conf.Set(nsConf, flagUser, packable.NewString(c.Username)); err != nil {
+		return err
+	}
+	if err := conf.Set(nsConf, flagPass, packable.NewString(c.Password)); err != nil {
+		return err
+	}
+	return nil
+}
+
+func fromFlags() error {
+	binds := make([]toBind, 0)
+	binds = append(binds, addFlag(flagPort, "51555", "port to bind to"))
+	binds = append(binds, addFlag(flagRoutes, "", "comma-separated routes to map, each as from:scheme://to.tld:port"))
+	binds = append(binds, addFlag(flagCert, "", "path to .crt"))
+	binds = append(binds, addFlag(flagKey, "", "path to .key"))
+	binds = append(binds, addFlag(flagUser, "", "basic auth username"))
+	binds = append(binds, addFlag(flagPass, "", "basic auth password"))
+	flag.Parse()
+
+	for _, bind := range binds {
+		confFlag := flag.Lookup(bind.flag)
+		if confFlag == nil || confFlag.Value.String() == "" {
+			continue
+		}
+		if err := conf.Set(nsConf, bind.flag, packable.NewString(*bind.value)); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func addFlag(key, def, help string) toBind {
+	v := flag.String(key, def, help)
+	return toBind{
+		flag:  key,
+		value: v,
+	}
+}