feat: integrate cobra+viper into the app

internal/howmuch/helper.go

@@ -0,0 +1,71 @@
+// MIT License
+//
+// Copyright (c) 2024 vinchent <vinchent@vinchent.xyz>
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+package howmuch
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+)
+
+const (
+	defaultConfigName = "howmuch"
+	homeConfigFolder  = ".howmuch"
+	envPrevfix        = "HOWMUCH"
+	configType        = "yaml"
+)
+
+// initConfig reads in config file and ENV variables if set.
+func initConfig() {
+	if cfgFile != "" {
+		// Use config file from the flag.
+		viper.SetConfigFile(cfgFile)
+	} else {
+		home, err := os.UserHomeDir()
+		cobra.CheckErr(err)
+
+		viper.AddConfigPath(filepath.Join(home, homeConfigFolder))
+		viper.AddConfigPath(".")
+
+		viper.SetConfigType(configType)
+		viper.SetConfigName(defaultConfigName)
+	}
+
+	viper.AutomaticEnv() // read in environment variables that match
+
+	viper.SetEnvPrefix(envPrevfix)
+
+	// replace . - to _ in the envvar
+	replacer := strings.NewReplacer(".", "_", "-", "_")
+	viper.SetEnvKeyReplacer(replacer)
+
+	if err := viper.ReadInConfig(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+	}
+
+	fmt.Fprintln(os.Stdout, "Using config file:", viper.ConfigFileUsed())
+}

internal/howmuch/howmuch.go

@@ -23,13 +23,17 @@
 package howmuch
 
 import (
+	"encoding/json"
 	"fmt"
 	"net/http"
 
 	"github.com/gin-gonic/gin"
 	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
 )
 
+var cfgFile string
+
 func errArgsForNoArgCommand(cmd string, args string) error {
 	return fmt.Errorf("%q does not take any argument, got %q", cmd, args)
 }
@@ -54,12 +58,30 @@ to share their expense of an event or a trip`,
 		},
 		SilenceUsage: true,
 	}
+	cobra.OnInitialize(initConfig)
+
+	// Here you will define your flags and configuration settings.
+	// Cobra supports persistent flags, which, if defined here,
+	// will be global for your application.
+
+	rootCmd.PersistentFlags().
+		StringVarP(&cfgFile, "config", "c", "", "path to config file. Default config if left empty")
+
+	// Cobra also supports local flags, which will only run
+	// when this action is called directly.
+	rootCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
+
 	return rootCmd
 }
 
 func run() error {
 	fmt.Println("How much do I owe you?")
 
+	settings, _ := json.MarshalIndent(viper.AllSettings(), "", "  ")
+
+	fmt.Println(string(settings))
+	fmt.Println(viper.GetString("db.username"))
+
 	r := gin.Default()
 
 	r.GET("/", func(ctx *gin.Context) {