Implement structured logging using log/slog package

internal/api/middleware.go

@@ -5,11 +5,11 @@ package api // import "miniflux.app/v2/internal/api"
 
 import (
 	"context"
+	"log/slog"
 	"net/http"
 
 	"miniflux.app/v2/internal/http/request"
 	"miniflux.app/v2/internal/http/response/json"
-	"miniflux.app/v2/internal/logger"
 	"miniflux.app/v2/internal/storage"
 )
 
@@ -40,25 +40,37 @@ func (m *middleware) apiKeyAuth(next http.Handler) http.Handler {
 		token := r.Header.Get("X-Auth-Token")
 
 		if token == "" {
-			logger.Debug("[API][TokenAuth] [ClientIP=%s] No API Key provided, go to the next middleware", clientIP)
+			slog.Debug("[API] Skipped API token authentication because no API Key has been provided",
+				slog.String("client_ip", clientIP),
+				slog.String("user_agent", r.UserAgent()),
+			)
 			next.ServeHTTP(w, r)
 			return
 		}
 
 		user, err := m.store.UserByAPIKey(token)
 		if err != nil {
-			logger.Error("[API][TokenAuth] %v", err)
 			json.ServerError(w, r, err)
 			return
 		}
 
 		if user == nil {
-			logger.Error("[API][TokenAuth] [ClientIP=%s] No user found with the given API key", clientIP)
+			slog.Warn("[API] No user found with the provided API key",
+				slog.Bool("authentication_failed", true),
+				slog.String("client_ip", clientIP),
+				slog.String("user_agent", r.UserAgent()),
+			)
 			json.Unauthorized(w, r)
 			return
 		}
 
-		logger.Info("[API][TokenAuth] [ClientIP=%s] User authenticated: %s", clientIP, user.Username)
+		slog.Info("[API] User authenticated successfully with the API Token Authentication",
+			slog.Bool("authentication_successful", true),
+			slog.String("client_ip", clientIP),
+			slog.String("user_agent", r.UserAgent()),
+			slog.String("username", user.Username),
+		)
+
 		m.store.SetLastLogin(user.ID)
 		m.store.SetAPIKeyUsedTimestamp(user.ID, token)
 
@@ -84,37 +96,60 @@ func (m *middleware) basicAuth(next http.Handler) http.Handler {
 		clientIP := request.ClientIP(r)
 		username, password, authOK := r.BasicAuth()
 		if !authOK {
-			logger.Debug("[API][BasicAuth] [ClientIP=%s] No authentication headers sent", clientIP)
+			slog.Warn("[API] No Basic HTTP Authentication header sent with the request",
+				slog.Bool("authentication_failed", true),
+				slog.String("client_ip", clientIP),
+				slog.String("user_agent", r.UserAgent()),
+			)
 			json.Unauthorized(w, r)
 			return
 		}
 
 		if username == "" || password == "" {
-			logger.Error("[API][BasicAuth] [ClientIP=%s] Empty username or password", clientIP)
+			slog.Warn("[API] Empty username or password provided during Basic HTTP Authentication",
+				slog.Bool("authentication_failed", true),
+				slog.String("client_ip", clientIP),
+				slog.String("user_agent", r.UserAgent()),
+			)
 			json.Unauthorized(w, r)
 			return
 		}
 
 		if err := m.store.CheckPassword(username, password); err != nil {
-			logger.Error("[API][BasicAuth] [ClientIP=%s] Invalid username or password: %s", clientIP, username)
+			slog.Warn("[API] Invalid username or password provided during Basic HTTP Authentication",
+				slog.Bool("authentication_failed", true),
+				slog.String("client_ip", clientIP),
+				slog.String("user_agent", r.UserAgent()),
+				slog.String("username", username),
+			)
 			json.Unauthorized(w, r)
 			return
 		}
 
 		user, err := m.store.UserByUsername(username)
 		if err != nil {
-			logger.Error("[API][BasicAuth] %v", err)
 			json.ServerError(w, r, err)
 			return
 		}
 
 		if user == nil {
-			logger.Error("[API][BasicAuth] [ClientIP=%s] User not found: %s", clientIP, username)
+			slog.Warn("[API] User not found while using Basic HTTP Authentication",
+				slog.Bool("authentication_failed", true),
+				slog.String("client_ip", clientIP),
+				slog.String("user_agent", r.UserAgent()),
+				slog.String("username", username),
+			)
 			json.Unauthorized(w, r)
 			return
 		}
 
-		logger.Info("[API][BasicAuth] [ClientIP=%s] User authenticated: %s", clientIP, username)
+		slog.Info("[API] User authenticated successfully with the Basic HTTP Authentication",
+			slog.Bool("authentication_successful", true),
+			slog.String("client_ip", clientIP),
+			slog.String("user_agent", r.UserAgent()),
+			slog.String("username", username),
+		)
+
 		m.store.SetLastLogin(user.ID)
 
 		ctx := r.Context()

internal/cli/cleanup_tasks.go

@@ -4,10 +4,10 @@
 package cli // import "miniflux.app/v2/internal/cli"
 
 import (
+	"log/slog"
 	"time"
 
 	"miniflux.app/v2/internal/config"
-	"miniflux.app/v2/internal/logger"
 	"miniflux.app/v2/internal/metric"
 	"miniflux.app/v2/internal/model"
 	"miniflux.app/v2/internal/storage"
@@ -16,13 +16,18 @@ import (
 func runCleanupTasks(store *storage.Storage) {
 	nbSessions := store.CleanOldSessions(config.Opts.CleanupRemoveSessionsDays())
 	nbUserSessions := store.CleanOldUserSessions(config.Opts.CleanupRemoveSessionsDays())
-	logger.Info("[Sessions] Removed %d application sessions and %d user sessions", nbSessions, nbUserSessions)
+	slog.Info("Sessions cleanup completed",
+		slog.Int64("application_sessions_removed", nbSessions),
+		slog.Int64("user_sessions_removed", nbUserSessions),
+	)
 
 	startTime := time.Now()
 	if rowsAffected, err := store.ArchiveEntries(model.EntryStatusRead, config.Opts.CleanupArchiveReadDays(), config.Opts.CleanupArchiveBatchSize()); err != nil {
-		logger.Error("[ArchiveReadEntries] %v", err)
+		slog.Error("Unable to archive read entries", slog.Any("error", err))
 	} else {
-		logger.Info("[ArchiveReadEntries] %d entries changed", rowsAffected)
+		slog.Info("Archiving read entries completed",
+			slog.Int64("read_entries_archived", rowsAffected),
+		)
 
 		if config.Opts.HasMetricsCollector() {
 			metric.ArchiveEntriesDuration.WithLabelValues(model.EntryStatusRead).Observe(time.Since(startTime).Seconds())
@@ -31,9 +36,11 @@ func runCleanupTasks(store *storage.Storage) {
 
 	startTime = time.Now()
 	if rowsAffected, err := store.ArchiveEntries(model.EntryStatusUnread, config.Opts.CleanupArchiveUnreadDays(), config.Opts.CleanupArchiveBatchSize()); err != nil {
-		logger.Error("[ArchiveUnreadEntries] %v", err)
+		slog.Error("Unable to archive unread entries", slog.Any("error", err))
 	} else {
-		logger.Info("[ArchiveUnreadEntries] %d entries changed", rowsAffected)
+		slog.Info("Archiving unread entries completed",
+			slog.Int64("unread_entries_archived", rowsAffected),
+		)
 
 		if config.Opts.HasMetricsCollector() {
 			metric.ArchiveEntriesDuration.WithLabelValues(model.EntryStatusUnread).Observe(time.Since(startTime).Seconds())

internal/cli/cli.go

@@ -6,11 +6,12 @@ package cli // import "miniflux.app/v2/internal/cli"
 import (
 	"flag"
 	"fmt"
+	"log/slog"
+	"os"
 
 	"miniflux.app/v2/internal/config"
 	"miniflux.app/v2/internal/database"
 	"miniflux.app/v2/internal/locale"
-	"miniflux.app/v2/internal/logger"
 	"miniflux.app/v2/internal/storage"
 	"miniflux.app/v2/internal/ui/static"
 	"miniflux.app/v2/internal/version"
@@ -74,26 +75,26 @@ func Parse() {
 	if flagConfigFile != "" {
 		config.Opts, err = cfg.ParseFile(flagConfigFile)
 		if err != nil {
-			logger.Fatal("%v", err)
+			printErrorAndExit(err)
 		}
 	}
 
 	config.Opts, err = cfg.ParseEnvironmentVariables()
 	if err != nil {
-		logger.Fatal("%v", err)
+		printErrorAndExit(err)
 	}
 
 	if flagConfigDump {
 		fmt.Print(config.Opts)
 		return
 	}
 
-	if config.Opts.LogDateTime() {
-		logger.EnableDateTime()
+	if flagDebugMode {
+		config.Opts.SetLogLevel("debug")
 	}
 
-	if flagDebugMode || config.Opts.HasDebugMode() {
-		logger.EnableDebug()
+	if err := InitializeDefaultLogger(config.Opts.LogLevel(), os.Stderr, config.Opts.LogFormat(), config.Opts.LogDateTime()); err != nil {
+		printErrorAndExit(err)
 	}
 
 	if flagHealthCheck != "" {
@@ -112,25 +113,25 @@ func Parse() {
 	}
 
 	if config.Opts.IsDefaultDatabaseURL() {
-		logger.Info("The default value for DATABASE_URL is used")
+		slog.Info("The default value for DATABASE_URL is used")
 	}
 
-	logger.Debug("Loading translations...")
+	slog.Debug("Loading translations...")
 	if err := locale.LoadCatalogMessages(); err != nil {
-		logger.Fatal("Unable to load translations: %v", err)
+		printErrorAndExit(err)
 	}
 
-	logger.Debug("Loading static assets...")
+	slog.Debug("Loading static assets...")
 	if err := static.CalculateBinaryFileChecksums(); err != nil {
-		logger.Fatal("Unable to calculate binary files checksum: %v", err)
+		printErrorAndExit(err)
 	}
 
 	if err := static.GenerateStylesheetsBundles(); err != nil {
-		logger.Fatal("Unable to generate Stylesheet bundles: %v", err)
+		printErrorAndExit(err)
 	}
 
 	if err := static.GenerateJavascriptBundles(); err != nil {
-		logger.Fatal("Unable to generate Javascript bundles: %v", err)
+		printErrorAndExit(err)
 	}
 
 	db, err := database.NewConnectionPool(
@@ -140,19 +141,19 @@ func Parse() {
 		config.Opts.DatabaseConnectionLifetime(),
 	)
 	if err != nil {
-		logger.Fatal("Unable to initialize database connection pool: %v", err)
+		printErrorAndExit(err)
 	}
 	defer db.Close()
 
 	store := storage.NewStorage(db)
 
 	if err := store.Ping(); err != nil {
-		logger.Fatal("Unable to connect to the database: %v", err)
+		printErrorAndExit(err)
 	}
 
 	if flagMigrate {
 		if err := database.Migrate(db); err != nil {
-			logger.Fatal(`%v`, err)
+			printErrorAndExit(err)
 		}
 		return
 	}
@@ -180,12 +181,12 @@ func Parse() {
 	// Run migrations and start the daemon.
 	if config.Opts.RunMigrations() {
 		if err := database.Migrate(db); err != nil {
-			logger.Fatal(`%v`, err)
+			printErrorAndExit(err)
 		}
 	}
 
 	if err := database.IsSchemaUpToDate(db); err != nil {
-		logger.Fatal(`You must run the SQL migrations, %v`, err)
+		printErrorAndExit(err)
 	}
 
 	// Create admin user and start the daemon.
@@ -205,3 +206,8 @@ func Parse() {
 
 	startDaemon(store)
 }
+
+func printErrorAndExit(err error) {
+	fmt.Fprintf(os.Stderr, "%v\n", err)
+	os.Exit(1)
+}

internal/cli/create_admin.go

@@ -5,10 +5,10 @@ package cli // import "miniflux.app/v2/internal/cli"
 
 import (
 	"fmt"
+	"log/slog"
 	"os"
 
 	"miniflux.app/v2/internal/config"
-	"miniflux.app/v2/internal/logger"
 	"miniflux.app/v2/internal/model"
 	"miniflux.app/v2/internal/storage"
 	"miniflux.app/v2/internal/validator"
@@ -26,7 +26,9 @@ func createAdmin(store *storage.Storage) {
 	}
 
 	if store.UserExists(userCreationRequest.Username) {
-		logger.Info(`User %q already exists, skipping creation`, userCreationRequest.Username)
+		slog.Info("Skipping admin user creation because it already exists",
+			slog.String("username", userCreationRequest.Username),
+		)
 		return
 	}
 

internal/cli/daemon.go

@@ -5,6 +5,7 @@ package cli // import "miniflux.app/v2/internal/cli"
 
 import (
 	"context"
+	"log/slog"
 	"net/http"
 	"os"
 	"os/signal"
@@ -13,15 +14,14 @@ import (
 
 	"miniflux.app/v2/internal/config"
 	httpd "miniflux.app/v2/internal/http/server"
-	"miniflux.app/v2/internal/logger"
 	"miniflux.app/v2/internal/metric"
 	"miniflux.app/v2/internal/storage"
 	"miniflux.app/v2/internal/systemd"
 	"miniflux.app/v2/internal/worker"
 )
 
 func startDaemon(store *storage.Storage) {
-	logger.Info("Starting daemon...")
+	slog.Info("Starting daemon...")
 
 	stop := make(chan os.Signal, 1)
 	signal.Notify(stop, os.Interrupt)
@@ -44,26 +44,26 @@ func startDaemon(store *storage.Storage) {
 	}
 
 	if systemd.HasNotifySocket() {
-		logger.Info("Sending readiness notification to Systemd")
+		slog.Info("Sending readiness notification to Systemd")
 
 		if err := systemd.SdNotify(systemd.SdNotifyReady); err != nil {
-			logger.Error("Unable to send readiness notification to systemd: %v", err)
+			slog.Error("Unable to send readiness notification to systemd", slog.Any("error", err))
 		}
 
 		if config.Opts.HasWatchdog() && systemd.HasSystemdWatchdog() {
-			logger.Info("Activating Systemd watchdog")
+			slog.Info("Activating Systemd watchdog")
 
 			go func() {
 				interval, err := systemd.WatchdogInterval()
 				if err != nil {
-					logger.Error("Unable to parse watchdog interval from systemd: %v", err)
+					slog.Error("Unable to get watchdog interval from systemd", slog.Any("error", err))
 					return
 				}
 
 				for {
-					err := store.Ping()
-					if err != nil {
-						logger.Error(`Systemd Watchdog: %v`, err)
+
+					if err := store.Ping(); err != nil {
+						slog.Error("Unable to ping database", slog.Any("error", err))
 					} else {
 						systemd.SdNotify(systemd.SdNotifyWatchdog)
 					}
@@ -75,13 +75,13 @@ func startDaemon(store *storage.Storage) {
 	}
 
 	<-stop
-	logger.Info("Shutting down the process...")
+	slog.Info("Shutting down the process")
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
 
 	if httpServer != nil {
 		httpServer.Shutdown(ctx)
 	}
 
-	logger.Info("Process gracefully stopped")
+	slog.Info("Process gracefully stopped")
 }