Add Inner Ring code

cmd/neofs-node/modules/fix/config/config.go

@@ -0,0 +1,53 @@
+package config
+
+import (
+	"strings"
+
+	"github.com/spf13/viper"
+)
+
+// Params groups the parameters of configuration.
+type Params struct {
+	File    string
+	Type    string
+	Prefix  string
+	Name    string
+	Version string
+
+	AppDefaults func(v *viper.Viper)
+}
+
+// NewConfig is a configuration tool's constructor.
+func NewConfig(p Params) (v *viper.Viper, err error) {
+	v = viper.New()
+	v.SetEnvPrefix(p.Prefix)
+	v.AutomaticEnv()
+	v.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
+
+	v.SetDefault("app.name", p.Name)
+	v.SetDefault("app.version", p.Version)
+
+	if p.AppDefaults != nil {
+		p.AppDefaults(v)
+	}
+
+	if p.fromFile() {
+		v.SetConfigFile(p.File)
+		v.SetConfigType(p.safeType())
+
+		err = v.ReadInConfig()
+	}
+
+	return v, err
+}
+
+func (p Params) fromFile() bool {
+	return p.File != ""
+}
+
+func (p Params) safeType() string {
+	if p.Type == "" {
+		p.Type = "yaml"
+	}
+	return strings.ToLower(p.Type)
+}