Adding a simple toml parser and cmd-line parser

cmd/urchin/main.go

@@ -1,19 +1,62 @@
 package main
 
 import (
+	"os"
+
 	_ "github.com/go-sql-driver/mysql"
 	"github.com/matheusgomes28/urchin/app"
 	"github.com/matheusgomes28/urchin/common"
 	"github.com/matheusgomes28/urchin/database"
 	"github.com/rs/zerolog/log"
 )
 
+type programArgs struct {
+	config string
+}
+
+func readArguments(args []string) programArgs {
+
+	var program_args programArgs
+	arg_index := 0
+
+	for ; arg_index < len(args); arg_index++ {
+		arg := args[arg_index]
+		arg_val := ""
+		if arg == "--config" {
+			if argval_index := arg_index + 1; argval_index < len(args) {
+				arg_val = args[argval_index]
+				arg_index++
+			}
+			program_args.config = arg_val
+		}
+		arg_index++
+	}
+
+	return program_args
+}
+
 func main() {
 	/// Load global application settings
-	app_settings, err := common.LoadSettings()
-	if err != nil {
-		log.Error().Msgf("could not get app settings: %v\n", err)
-		return
+
+	var app_settings common.AppSettings
+	arguments := readArguments(os.Args)
+	if arguments.config != "" {
+		log.Info().Msgf("reading config file %s", arguments.config)
+		settings, err := common.ReadConfigJson(arguments.config)
+		if err != nil {
+			log.Error().Msgf("could not read config file: %v", err)
+			os.Exit(-1)
+		}
+
+		app_settings = settings
+	} else {
+		log.Info().Msgf("no config file, reading environment variables")
+		settings, err := common.LoadSettings()
+		if err != nil {
+			log.Error().Msgf("could not load settings: %v", err)
+			os.Exit(-1)
+		}
+		app_settings = settings
 	}
 
 	db_connection, err := database.MakeSqlConnection(
@@ -25,9 +68,11 @@ func main() {
 	)
 	if err != nil {
 		log.Error().Msgf("could not create database connection: %v", err)
+		os.Exit(-1)
 	}
 
 	if err = app.Run(app_settings, &db_connection); err != nil {
 		log.Error().Msgf("could not run app: %v", err)
+		os.Exit(-1)
 	}
 }

common/app_settings.go

@@ -4,15 +4,17 @@ import (
 	"fmt"
 	"os"
 	"strconv"
+
+	"github.com/BurntSushi/toml"
 )
 
 type AppSettings struct {
-	DatabaseAddress  string
-	DatabasePort     int
-	DatabaseUser     string
-	DatabasePassword string
-	DatabaseName     string
-	WebserverPort    string
+	DatabaseAddress  string `toml:"database_address"`
+	DatabasePort     int    `toml:"database_port"`
+	DatabaseUser     string `toml:"database_user"`
+	DatabasePassword string `toml:"database_password"`
+	DatabaseName     string `toml:"database_name"`
+	WebserverPort    string `toml:"webserver_port"`
 }
 
 func LoadSettings() (AppSettings, error) {
@@ -61,3 +63,13 @@ func LoadSettings() (AppSettings, error) {
 		WebserverPort:    webserver_port,
 	}, nil
 }
+
+func ReadConfigJson(filepath string) (AppSettings, error) {
+	var config AppSettings
+	_, err := toml.DecodeFile(filepath, &config)
+	if err != nil {
+		return AppSettings{}, err
+	}
+
+	return config, nil
+}

go.mod

@@ -12,6 +12,7 @@ require (
 )
 
 require (
+	github.com/BurntSushi/toml v1.3.2 // indirect
 	github.com/bytedance/sonic v1.9.1 // indirect
 	github.com/chenzhuoyu/base64x v0.0.0-20221115062448-fe3a3abad311 // indirect
 	github.com/gabriel-vasile/mimetype v1.4.2 // indirect

go.sum

@@ -1,3 +1,5 @@
+github.com/BurntSushi/toml v1.3.2 h1:o7IhLm0Msx3BaB+n3Ag7L8EVlByGnpq14C4YWiu/gL8=
+github.com/BurntSushi/toml v1.3.2/go.mod h1:CxXYINrC8qIiEnFrOxCa7Jy5BFHlXnUU2pbicEuybxQ=
 github.com/a-h/templ v0.2.543 h1:8YyLvyUtf0/IE2nIwZ62Z/m2o2NqwhnMynzOL78Lzbk=
 github.com/a-h/templ v0.2.543/go.mod h1:jP908DQCwI08IrnTalhzSEH9WJqG/Q94+EODQcJGFUA=
 github.com/bytedance/sonic v1.5.0/go.mod h1:ED5hyg4y6t3/9Ku1R6dU/4KyJ48DZ4jPhfY1O2AihPM=