Add JSON structured logging

.gitignore

@@ -1,2 +1,3 @@
 bot.token
 bingobot
+bingobot.log

config.go

@@ -15,6 +15,7 @@ type AppConfig struct {
 	LogMaxBackups  int    `yaml:"log_max_backups"`
 	LogMaxAgeDays  int    `yaml:"log_max_age_days"`
 	LogCompression bool   `yaml:"log_compression"`
+	LogAddSource   bool   `yaml:"log_add_source"`
 }
 
 func parseConfigs() error {
@@ -43,9 +44,10 @@ func parseConfigs() error {
 
 func setDefaults() {
 	viper.SetDefault("LogFile", "bingobot.log")
-	viper.SetDefault("LogDir", "bingobot.log")
+	viper.SetDefault("LogDir", "log")
 	viper.SetDefault("LogMaxSizeMB", 500)
 	viper.SetDefault("LogMaxBackups", 3)
 	viper.SetDefault("LogMaxAgeDays", 365)
 	viper.SetDefault("LogCompression", false)
+	viper.SetDefault("LogAddSource", true)
 }

go.mod

@@ -5,6 +5,7 @@ go 1.23.2
 require (
 	github.com/bwmarrin/discordgo v0.28.1
 	github.com/spf13/viper v1.19.0
+	gopkg.in/natefinch/lumberjack.v2 v2.2.1
 )
 
 require (

go.sum

@@ -78,6 +78,8 @@ gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 h1:YR8cESwS4TdDjEe65xsg0ogR
 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/ini.v1 v1.67.0 h1:Dgnx+6+nfE+IfzjUEISNeydPJh9AXNNsWbGP9KzCsOA=
 gopkg.in/ini.v1 v1.67.0/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k=
+gopkg.in/natefinch/lumberjack.v2 v2.2.1 h1:bBRl1b0OH9s/DuPhuXpNl+VtCaJXFZ5/uEFST95x9zc=
+gopkg.in/natefinch/lumberjack.v2 v2.2.1/go.mod h1:YD8tP3GAjkrDg1eZH7EGmyESg/lsYskCTPBJVb9jqSc=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

log.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	"log/slog"
+	"path/filepath"
+
+	"gopkg.in/natefinch/lumberjack.v2"
+)
+
+var (
+	Log *slog.Logger
+)
+
+func initLogger() {
+
+	lj := &lumberjack.Logger{
+		Filename:   filepath.Join(appConfig.LogDir, appConfig.LogFile),
+		MaxSize:    appConfig.LogMaxSizeMB,
+		MaxBackups: appConfig.LogMaxBackups,
+		MaxAge:     appConfig.LogMaxAgeDays,
+		Compress:   appConfig.LogCompression,
+	}
+
+	Log = slog.New(slog.NewJSONHandler(lj, &slog.HandlerOptions{
+		AddSource: true,
+	}))
+}

main.go

@@ -27,25 +27,37 @@ func main() {
 		log.Fatal(err)
 	}
 
-	startBot()
+	initLogger()
+
+	err = startBot()
+
+	if err != nil {
+		log.Fatal(err)
+	}
 }
 
-func startBot() {
+func startBot() error {
 	session, _ := discordgo.New("Bot " + *Token)
 
 	err := session.Open()
 	if err != nil {
-		log.Fatalf("could not open session: %s", err)
+		Log.Error("could not open discord session", "type", "error", "error", err)
+		return err
 	}
 
+	Log.Info("shutting down gracefully", "type", "shutdown")
+
 	sigch := make(chan os.Signal, 1)
 	signal.Notify(sigch, os.Interrupt)
 	<-sigch
 
-	log.Printf("shutting down gracefully...")
+	Log.Info("shutting down gracefully", "type", "shutdown")
 
 	err = session.Close()
 	if err != nil {
-		log.Printf("could not close session gracefully: %s", err)
+		Log.Error("could not close discord session gracefully", "type", "error", "error", err)
+		return err
 	}
+
+	return nil
 }