feat: add configuration file and environment

main/configuration.go

@@ -0,0 +1,87 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/rs/zerolog/log"
+)
+
+type Configuration struct {
+	Port              string `json:"port"`
+	DatabaseDirectory string `json:"database_directory"`
+}
+
+func getDefaultConfig() Configuration {
+	return Configuration{
+		Port:              "8080",
+		DatabaseDirectory: ".",
+	}
+
+}
+
+func LoadConfiguration(configurationFilePath string) (Configuration, error) {
+	config, err := fromFile(configurationFilePath)
+	if err != nil {
+		log.Info().Msg("failed to load configuration from file, using default values")
+	}
+	config.Port = os.Getenv("HTTP_PORT")
+	config.DatabaseDirectory = os.Getenv("DATABASE_DIRECTORY")
+
+	config = mergeConfig(getDefaultConfig(), config)
+
+	err = checkConfiguration(&config)
+	if err != nil {
+		return config, err
+	}
+
+	return config, nil
+}
+
+func fromFile(filePath string) (Configuration, error) {
+	file, err := os.Open(filePath)
+	if err != nil {
+		return Configuration{}, err
+	}
+
+	jsonData, err := io.ReadAll(file)
+	if err != nil {
+		return Configuration{}, err
+	}
+
+	var config Configuration
+	err = json.Unmarshal(jsonData, &config)
+	if err != nil {
+		return Configuration{}, err
+	}
+	return config, nil
+}
+
+func mergeConfig(base Configuration, override Configuration) Configuration {
+	mergedConfig := base
+
+	if override.Port != "" {
+		mergedConfig.Port = override.Port
+	}
+
+	if override.DatabaseDirectory != "" {
+		mergedConfig.DatabaseDirectory = override.DatabaseDirectory
+	}
+
+	return mergedConfig
+}
+
+func checkConfiguration(configuration *Configuration) error {
+	databaseDirectory := configuration.DatabaseDirectory
+	if !checkDirectoryPath(databaseDirectory) {
+		return fmt.Errorf("database directory %s does not exist", databaseDirectory)
+	}
+	return nil
+}
+
+func checkDirectoryPath(directoryPath string) bool {
+	_, err := os.Stat(directoryPath)
+	return !os.IsNotExist(err)
+}

main/main.go

@@ -10,16 +10,19 @@ import (
 	"github.com/rs/zerolog/log"
 )
 
-const USER_DATABASE_DIR = "."
-const WEB_SERVER_PORT = "8080"
-
 func main() {
 	initializeLogger()
 	log.Info().Msg("starting playback device server")
 
+	configuration, err := LoadConfiguration("config.json")
+	if err != nil {
+		log.Error().Err(err).Msg("configuration error")
+		os.Exit(1)
+	}
+
 	userDatabase := users.UserDatabase{}
-	userDatabase.SetDirectory(USER_DATABASE_DIR)
-	err := userDatabase.Initialize()
+	userDatabase.SetDirectory(configuration.DatabaseDirectory)
+	err = userDatabase.Initialize()
 	if err != nil {
 		log.Error().Err(err).Msg("failed to initialize user database")
 		os.Exit(1)
@@ -34,7 +37,7 @@ func main() {
 
 	webServer := server.WebServer{}
 	webServer.SetWebAppDirectoryPath("www")
-	webServer.SetPort(WEB_SERVER_PORT)
+	webServer.SetPort(configuration.Port)
 	webServer.Initialize()
 	defer webServer.Close()