fix: logger initialization before flags parsing (#7372)

Signed-off-by: knqyf263 <[email protected]>
Co-authored-by: knqyf263 <[email protected]>

pkg/log/deferred.go

@@ -0,0 +1,62 @@
+package log
+
+import (
+ "context"
+ "log/slog"
+ "slices"
+)
+
+func init() {
+ // Set the default logger so that logs are buffered until the logger is initialized.
+ slog.SetDefault(New(&DeferredHandler{records: new([]deferredRecord)}))
+}
+
+// DeferredHandler is needed to save logs and print them after calling `PrintLogs()` command.
+// For example, this may be necessary when the logger is not yet initialized, but messages need to be transmitted.
+// In this case, the messages are saved and printed when the logger is initialized.
+type DeferredHandler struct {
+ attrs []slog.Attr
+
+ // Shared with all instances of the handler.
+ // NOTE: non-thread safe
+ records *[]deferredRecord
+}
+
+type deferredRecord struct {
+ ctx context.Context
+ slog.Record
+}
+
+func (*DeferredHandler) Enabled(context.Context, slog.Level) bool {
+ return true
+}
+
+func (d *DeferredHandler) Handle(ctx context.Context, record slog.Record) error {
+ record.AddAttrs(d.attrs...)
+ *d.records = append(*d.records, deferredRecord{
+ ctx: ctx,
+ Record: record,
+ })
+ return nil
+}
+
+func (d *DeferredHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
+ h := *d
+ h.attrs = slices.Clip(d.attrs)
+ h.attrs = append(h.attrs, attrs...)
+ return &h
+}
+
+func (*DeferredHandler) WithGroup(_ string) slog.Handler {
+ panic("WithGroup is not implemented")
+}
+
+func (d *DeferredHandler) Flush(h slog.Handler) {
+ for _, record := range *d.records {
+ if !h.Enabled(record.ctx, record.Level) {
+ continue
+ }
+ _ = h.Handle(record.ctx, record.Record)
+ }
+ d.records = nil
+}

pkg/log/logger.go

@@ -33,11 +33,18 @@ func New(h slog.Handler) *Logger {
  return slog.New(h)
 }
 
-// InitLogger initialize the logger variable
+// InitLogger initializes the logger variable and flushes the buffered logs if needed.
 func InitLogger(debug, disable bool) {
  level := lo.Ternary(debug, slog.LevelDebug, slog.LevelInfo)
  out := lo.Ternary(disable, io.Discard, io.Writer(os.Stderr))
- slog.SetDefault(New(NewHandler(out, &Options{Level: level})))
+ h := NewHandler(out, &Options{Level: level})
+
+ // Flush the buffered logs if needed.
+ if d, ok := slog.Default().Handler().(*DeferredHandler); ok {
+ d.Flush(h)
+ }
+
+ slog.SetDefault(New(h))
 }
 
 var (