log: fix syncer causing errors

go/pkg/log/log.go

@@ -1,7 +1,7 @@
 package log
 
 import (
-	"errors"
+	"io"
 	"log/slog"
 	"net/http"
 	"os"
@@ -11,6 +11,7 @@ import (
 	"github.com/mattn/go-isatty"
 	slogmulti "github.com/samber/slog-multi"
 	"github.com/tigorlazuardi/bluemage/go/config"
+	"github.com/tigorlazuardi/bluemage/go/pkg/errs"
 	"github.com/tigorlazuardi/bluemage/go/pkg/telemetry"
 	"gopkg.in/natefinch/lumberjack.v2"
 )
@@ -20,8 +21,10 @@ func NewHandler(cfg *config.Config) (slog.Handler, func() error) {
 	cleanup := func() error { return nil }
 
 	if cfg.Bool("log.enable") {
-		log, sync := createStandardLogger(cfg)
-		cleanup = sync
+		log := createStandardLogger(cfg)
+		if closer, ok := log.(io.Closer); ok {
+			cleanup = closer.Close
+		}
 		handlers = append(handlers, log)
 	}
 
@@ -29,7 +32,7 @@ func NewHandler(cfg *config.Config) (slog.Handler, func() error) {
 		log, clean := createFileLogger(cfg)
 		cl := cleanup
 		cleanup = func() error {
-			return errors.Join(cl(), clean())
+			return errs.Join(cl(), clean())
 		}
 		handlers = append(handlers, log)
 	}
@@ -66,19 +69,16 @@ func createFileLogger(cfg *config.Config) (slog.Handler, func() error) {
 		AddSource: cfg.Bool("log.source"),
 		Level:     lvl,
 	}
-	return slog.NewJSONHandler(Lock(AddSync(output)), opts), output.Close
+	return slog.NewJSONHandler(Lock(output), opts), output.Close
 }
 
-func createStandardLogger(cfg *config.Config) (slog.Handler, func() error) {
-	var output WriteSyncer
-	var cleanup func() error
+func createStandardLogger(cfg *config.Config) slog.Handler {
+	var output WriteLocker
 
 	if strings.ToLower(cfg.String("log.output")) == "stdout" {
-		output = Lock(AddSync(colorable.NewColorableStdout()))
-		cleanup = output.Sync
+		output = Lock(colorable.NewColorableStdout())
 	} else {
-		output = Lock(AddSync(colorable.NewColorableStderr()))
-		cleanup = output.Sync
+		output = Lock(colorable.NewColorableStderr())
 	}
 
 	var lvl slog.Level
@@ -89,9 +89,9 @@ func createStandardLogger(cfg *config.Config) (slog.Handler, func() error) {
 	}
 
 	if isatty.IsTerminal(os.Stdout.Fd()) {
-		return NewPrettyHandler(output, opts), cleanup
+		return NewPrettyHandler(output, opts)
 	} else {
-		return slog.NewJSONHandler(output, opts), cleanup
+		return slog.NewJSONHandler(output, opts)
 	}
 }
 

go/pkg/log/pretty.go

@@ -17,7 +17,7 @@ import (
 
 type PrettyHandler struct {
 	opts         *slog.HandlerOptions
-	output       WriteSyncer
+	output       WriteLocker
 	replaceAttr  func(groups []string, attr slog.Attr) slog.Attr
 	withAttrs    []slog.Attr
 	withGroup    []string
@@ -27,7 +27,7 @@ type PrettyHandler struct {
 }
 
 // NewPrettyHandler creates a human friendly readable logs.
-func NewPrettyHandler(writer WriteSyncer, opts *slog.HandlerOptions) *PrettyHandler {
+func NewPrettyHandler(writer WriteLocker, opts *slog.HandlerOptions) *PrettyHandler {
 	if opts == nil {
 		opts = &slog.HandlerOptions{Level: slog.LevelDebug}
 	}
@@ -56,24 +56,24 @@ func NewPrettyHandler(writer WriteSyncer, opts *slog.HandlerOptions) *PrettyHand
 // and then flush the buffer.
 //
 // Flush blocks other log writes until it's done.
-func (pr *PrettyHandler) Flush() error {
+func (pr *PrettyHandler) Flush() {
 	pr.isFlushing.Store(true)
 	defer func() { pr.isFlushing.Store(false) }()
 	pr.wg.Wait()
-	err := pr.output.Sync()
 	for {
 		select {
 		// signal to handlers that flushing is done.
 		case pr.flushingChan <- struct{}{}:
 		default:
-			return err
+			return
 		}
 	}
 }
 
 // Sync attemps to flush the buffer of the underlying writer.
-func (pr *PrettyHandler) Sync() error {
-	return pr.output.Sync()
+func (pr *PrettyHandler) Close() error {
+	pr.Flush()
+	return nil
 }
 
 // Enabled implements slog.Handler interface.

go/pkg/log/writer.go

@@ -2,68 +2,27 @@ package log
 
 import (
 	"io"
-	"os"
 	"sync"
 )
 
-type WriteSyncer interface {
+type WriteLocker interface {
 	io.Writer
-	Sync() error
+	sync.Locker
 }
 
-// WrapOsFile wraps an *os.File in a WriteSyncer.
-//
-// To support multithreaded logging and to support
-// flushing the buffer before the program exits.
-func WrapOsFile(f *os.File) WriteSyncer {
-	return Lock(f)
-}
-
-// AddSync converts an io.Writer to a WriteSyncer. It attempts to be
-// intelligent: if the concrete type of the io.Writer implements WriteSyncer,
-// we'll use the existing Sync method. If it doesn't, we'll add a no-op Sync.
-func AddSync(w io.Writer) WriteSyncer {
-	switch w := w.(type) {
-	case WriteSyncer:
-		return w
-	default:
-		return writerWrapper{w}
-	}
-}
-
-type lockedWriteSyncer struct {
+type writeLock struct {
 	sync.Mutex
-	ws WriteSyncer
+	io.Writer
 }
 
 // Lock wraps a WriteSyncer in a mutex to make it safe for concurrent use. In
 // particular, *os.Files must be locked before use.
-func Lock(ws WriteSyncer) WriteSyncer {
-	if _, ok := ws.(*lockedWriteSyncer); ok {
+//
+// If w is already a WriteLocker, it will be returned as is.
+func Lock(w io.Writer) WriteLocker {
+	if wl, ok := w.(WriteLocker); ok {
 		// no need to layer on another lock
-		return ws
+		return wl
 	}
-	return &lockedWriteSyncer{ws: ws}
-}
-
-func (s *lockedWriteSyncer) Write(bs []byte) (int, error) {
-	s.Lock()
-	n, err := s.ws.Write(bs)
-	s.Unlock()
-	return n, err
-}
-
-func (s *lockedWriteSyncer) Sync() error {
-	s.Lock()
-	err := s.ws.Sync()
-	s.Unlock()
-	return err
-}
-
-type writerWrapper struct {
-	io.Writer
-}
-
-func (w writerWrapper) Sync() error {
-	return nil
+	return &writeLock{Writer: w}
 }