add viper configuration example and minor improvements - read HISTORY.md

_examples/configuration/viper/config/config.go

@@ -0,0 +1,54 @@
+package config
+
+import (
+	"fmt"
+
+	"github.com/kataras/iris/v12"
+	// Viper is a third-party package:
+	// go get github.com/spf13/viper
+	"github.com/spf13/viper"
+)
+
+func init() {
+	loadConfiguration()
+}
+
+// C is the configuration of the app.
+var C = struct {
+	Iris iris.Configuration
+	Addr struct {
+		Internal struct {
+			IP     string
+			Plain  int
+			Secure int
+		}
+	}
+	Locale struct {
+		Pattern   string
+		Default   string
+		Supported []string
+	}
+}{
+	Iris: iris.DefaultConfiguration(),
+	// other default values...
+}
+
+func loadConfiguration() {
+	viper.SetConfigName("config")     // name of config file (without extension)
+	viper.SetConfigType("yaml")       // REQUIRED if the config file does not have the extension in the name
+	viper.AddConfigPath("/etc/app/")  // path to look for the config file in
+	viper.AddConfigPath("$HOME/.app") // call multiple times to add many search paths
+	viper.AddConfigPath(".")          // optionally look for config in the working directory
+	err := viper.ReadInConfig()       // Find and read the config file
+	if err := viper.ReadInConfig(); err != nil {
+		if _, ok := err.(viper.ConfigFileNotFoundError); ok {
+		} else {
+			panic(fmt.Errorf("load configuration: %w", err))
+		}
+	}
+
+	err = viper.Unmarshal(&C)
+	if err != nil {
+		panic(fmt.Errorf("load configuration: unmarshal: %w", err))
+	}
+}