Merge pull request #3 from googlecloudrobotics/therjak/log

switch log output to json format

handler.go

@@ -15,124 +15,26 @@
 package ilog
 
 import (
-	"bytes"
-	"context"
-	"fmt"
 	"io"
 	"log/slog"
-	"sync"
-	"time"
 )
 
-type groupOrAttrs struct {
-	group string
-	attrs []slog.Attr
-}
-
-// LogHandler implements slog.Handler.
-// Use NewLogHandler to create instances with correct internal state.
-type LogHandler struct {
-	level  slog.Level
-	goas   []groupOrAttrs
-	mu     *sync.Mutex
-	writer io.Writer
-}
-
-// Enabled is part of the slog.Handler interface
-func (h *LogHandler) Enabled(_ context.Context, level slog.Level) bool {
-	return level >= h.level
-}
-
-// Handle is part of the slog.Handler interface
-func (h *LogHandler) Handle(_ context.Context, r slog.Record) error {
-	var buf bytes.Buffer
-	buf.Grow(1024) // should cover most log messages
-	if !r.Time.IsZero() {
-		buf.WriteString(r.Time.UTC().Format(time.RFC3339))
-		buf.WriteRune(' ')
-	}
-	buf.WriteString(r.Level.String())
-	buf.WriteRune(' ')
-	buf.WriteString(r.Message)
-	buf.WriteRune(' ')
-	// TODO: The layout of groups and extra attrs needs some work. So far they
-	// have not been used so it does not matter.
-	for _, goa := range h.goas {
-		if goa.group != "" {
-			buf.WriteString(goa.group)
-			buf.WriteString(": ")
-		} else {
-			for _, a := range goa.attrs {
-				h.appendAttr(&buf, a)
-			}
-		}
-	}
-
-	r.Attrs(func(a slog.Attr) bool {
-		h.appendAttr(&buf, a)
-		return true
-	})
-	buf.WriteRune('\n')
-	h.mu.Lock()
-	defer h.mu.Unlock()
-	_, err := h.writer.Write(buf.Bytes())
-	return err
-}
-
-func (h *LogHandler) appendAttr(w io.Writer, a slog.Attr) (int, error) {
-	if a.Equal(slog.Attr{}) {
-		return 0, nil
-	}
-	switch a.Value.Kind() {
-	case slog.KindString:
-		return fmt.Fprintf(w, "%q=%q ", a.Key, a.Value.String())
-	case slog.KindTime:
-		return fmt.Fprintf(w, "%q=%q ", a.Key, a.Value.Time().UTC().Format(time.RFC3339))
-	case slog.KindGroup:
-		// TODO: how to handle KindGroup?
-	default:
-		// slog.KindAny:
-		// slog.KindBool:
-		// slog.KindDuration:
-		// slog.KindFloat64:
-		// slog.KindInt64:
-		// slog.KindUint64:
-		// slog.KindLogValuer:
-		return fmt.Fprintf(w, "%q=%q ", a.Key, a.Value)
-	}
-	return 0, nil
-}
-
-func (h *LogHandler) withGroupOrAttrs(goa groupOrAttrs) *LogHandler {
-	h2 := *h
-	h2.goas = make([]groupOrAttrs, len(h.goas)+1)
-	copy(h2.goas, h.goas)
-	h2.goas[len(h2.goas)-1] = goa
-	return &h2
-}
-
-// WithGroup is part of the slog.Handler interface
-func (h *LogHandler) WithGroup(name string) slog.Handler {
-	if name == "" {
-		return h
-	}
-	return h.withGroupOrAttrs(groupOrAttrs{group: name})
-}
-
-// WithAttrs is part of the slog.Handler interface
-func (h *LogHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
-	if len(attrs) == 0 {
-		return h
-	}
-	return h.withGroupOrAttrs(groupOrAttrs{attrs: attrs})
-}
-
 // NewLogHandler creates a new LogHandler. Only log messages with log level l or
 // higher will get written to the writer.
-func NewLogHandler(l slog.Level, w io.Writer) *LogHandler {
-	return &LogHandler{
-		level:  l,
-		mu:     &sync.Mutex{},
-		writer: w,
-	}
+func NewLogHandler(l slog.Level, w io.Writer) *slog.JSONHandler {
+	return slog.NewJSONHandler(w, &slog.HandlerOptions{
+		AddSource: true,
+		Level:     l,
+		ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr {
+			switch a.Key {
+			case slog.MessageKey:
+				a.Key = "message"
+			case slog.TimeKey:
+				a.Key = "timestamp"
+			case slog.LevelKey:
+				a.Key = "severity"
+			}
+			return a
+		},
+	})
 }