Change logging format

pkg/cmd/helpers/logger.go

@@ -6,15 +6,18 @@ import (
 	"os"
 	"strings"
 
+	"github.com/cnoe-io/idpbuilder/pkg/logger"
 	"github.com/go-logr/logr"
 	"k8s.io/klog/v2"
 	ctrl "sigs.k8s.io/controller-runtime"
 )
 
 var (
-	LogLevel    string
-	LogLevelMsg = "Set the log verbosity. Supported values are: debug, info, warn, and error."
-	CmdLogger   logr.Logger
+	LogLevel         string
+	LogLevelMsg      = "Set the log verbosity. Supported values are: debug, info, warn, and error."
+	CmdLogger        logr.Logger
+	ColoredOutput    bool
+	ColoredOutputMsg = "Enable colored log messages."
 )
 
 func SetLogger() error {
@@ -23,7 +26,7 @@ func SetLogger() error {
 		return err
 	}
 
-	slogger := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: l}))
+	slogger := slog.New(logger.NewHandler(os.Stderr, logger.Options{Level: l, Colored: ColoredOutput}))
 	kslogger := slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: getKlogLevel(l)}))
 	logger := logr.FromSlogHandler(slogger.Handler())
 	klogger := logr.FromSlogHandler(kslogger.Handler())

pkg/cmd/root.go

@@ -20,6 +20,7 @@ var rootCmd = &cobra.Command{
 
 func init() {
 	rootCmd.PersistentFlags().StringVarP(&helpers.LogLevel, "log-level", "l", "info", helpers.LogLevelMsg)
+	rootCmd.PersistentFlags().BoolVar(&helpers.ColoredOutput, "color", false, helpers.ColoredOutputMsg)
 	rootCmd.AddCommand(create.CreateCmd)
 	rootCmd.AddCommand(get.GetCmd)
 	rootCmd.AddCommand(delete.DeleteCmd)

pkg/logger/handler.go

@@ -0,0 +1,228 @@
+package logger
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"log/slog"
+	"runtime"
+	"slices"
+	"sync"
+	"time"
+)
+
+// https://en.wikipedia.org/wiki/ANSI_escape_code
+const (
+	Reset              = "\033[0m"
+	White              = "\033[37m"
+	WhiteDim           = "\033[37;2m"
+	Green              = "\033[32m"
+	GreenDimUnderlined = "\033[32;2;4m"
+	Magenta            = "\033[35m"
+	BrightRed          = "\033[91m"
+	BrightYellow       = "\033[93m"
+	Cyan               = "\033[36m"
+	CyanDim            = "\033[36;2m"
+	// this mirrors the limit value from the internal slog package
+	maxBufferSize = 16384
+	dateFormat    = time.Stamp
+)
+
+var bufPool = sync.Pool{
+	New: func() any {
+		b := make([]byte, 0, 2048)
+		return &b
+	},
+}
+
+type Options struct {
+	AddSource  bool
+	Colored    bool
+	Level      slog.Leveler
+	TimeFormat string
+}
+
+// Handler is very similar to slog's commonHandler
+type Handler struct {
+	opts              Options
+	json              bool
+	preformattedAttrs []byte
+	groupPrefix       string
+	groups            []string
+	unopenedGroups    []string
+	nOpenGroups       int
+	mu                *sync.Mutex
+	w                 io.Writer
+}
+
+func NewHandler(out io.Writer, opts Options) *Handler {
+	return &Handler{
+		opts:              opts,
+		preformattedAttrs: make([]byte, 0),
+		unopenedGroups:    make([]string, 0),
+		nOpenGroups:       0,
+		mu:                &sync.Mutex{},
+		w:                 out,
+	}
+}
+
+func (h *Handler) clone() *Handler {
+	return &Handler{
+		opts:              h.opts,
+		json:              h.json,
+		preformattedAttrs: slices.Clip(h.preformattedAttrs),
+		groupPrefix:       h.groupPrefix,
+		groups:            slices.Clip(h.groups),
+		nOpenGroups:       h.nOpenGroups,
+		w:                 h.w,
+		mu:                h.mu,
+	}
+}
+
+func (h *Handler) Enabled(_ context.Context, level slog.Level) bool {
+	minLevel := slog.LevelInfo
+	if h.opts.Level != nil {
+		minLevel = h.opts.Level.Level()
+	}
+	return level >= minLevel
+}
+
+func (h *Handler) WithGroup(name string) slog.Handler {
+	if name == "" {
+		return h
+	}
+	h2 := h.clone()
+	h2.unopenedGroups = make([]string, len(h.unopenedGroups)+1)
+	copy(h2.unopenedGroups, h.unopenedGroups)
+	h2.unopenedGroups[len(h2.unopenedGroups)-1] = name
+	return h2
+}
+
+func (h *Handler) WithAttrs(as []slog.Attr) slog.Handler {
+	if len(as) == 0 {
+		return h
+	}
+	h2 := h.clone()
+	h2.preformattedAttrs = h2.appendUnopenedGroups(h2.preformattedAttrs)
+	h2.unopenedGroups = nil
+
+	for _, a := range as {
+		h2.preformattedAttrs = h2.appendAttr(h2.preformattedAttrs, a)
+	}
+	return h2
+}
+
+func (h *Handler) appendUnopenedGroups(buf []byte) []byte {
+	for _, g := range h.unopenedGroups {
+		buf = fmt.Appendf(buf, "%s ", g)
+	}
+	return buf
+}
+
+func (h *Handler) appendAttr(buf []byte, a slog.Attr) []byte {
+	a.Value = a.Value.Resolve()
+	if a.Equal(slog.Attr{}) {
+		return buf
+	}
+
+	switch a.Value.Kind() {
+	case slog.KindGroup:
+		attrs := a.Value.Group()
+		if len(attrs) == 0 {
+			return buf
+		}
+		if a.Key != "" {
+			for _, ga := range attrs {
+				buf = h.appendAttr(buf, ga)
+			}
+		}
+	default:
+		if a.Key == "" || a.Value.String() == "" {
+			return buf
+		}
+		buf = h.appendKeyValuePair(buf, a)
+	}
+	return buf
+}
+
+func (h *Handler) Handle(ctx context.Context, record slog.Record) error {
+	bufp := bufPool.Get().(*[]byte)
+	buf := *bufp
+
+	defer func() {
+		*bufp = buf
+		free(bufp)
+	}()
+
+	// append time, level, then message.
+	if h.opts.Colored {
+		buf = fmt.Appendf(buf, WhiteDim)
+		buf = slog.Time(slog.TimeKey, record.Time).Value.Time().AppendFormat(buf, fmt.Sprintf("%s%s ", dateFormat, Reset))
+
+		var color string
+		switch record.Level {
+		case slog.LevelDebug:
+			color = Magenta
+		case slog.LevelInfo:
+			color = Green
+		case slog.LevelWarn:
+			color = BrightYellow
+		case slog.LevelError:
+			color = BrightRed
+		default:
+			color = Magenta
+		}
+		buf = fmt.Appendf(buf, "%s%s%s ", color, record.Level.String(), Reset)
+
+		buf = fmt.Appendf(buf, "%s%s%s ", Cyan, record.Message, Reset)
+	} else {
+		buf = slog.Time(slog.TimeKey, record.Time).Value.Time().AppendFormat(buf, fmt.Sprintf("%s ", dateFormat))
+		buf = fmt.Appendf(buf, "%s ", record.Level)
+		buf = fmt.Appendf(buf, "%s ", record.Message)
+	}
+
+	if h.opts.AddSource {
+		buf = h.appendAttr(buf, slog.Any(slog.SourceKey, source(record)))
+	}
+
+	buf = append(buf, h.preformattedAttrs...)
+	if record.NumAttrs() > 0 {
+		buf = h.appendUnopenedGroups(buf)
+		record.Attrs(func(a slog.Attr) bool {
+			buf = h.appendAttr(buf, a)
+			return true
+		})
+	}
+	buf = append(buf, "\n"...)
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	_, err := h.w.Write(buf)
+	return err
+}
+
+func (h *Handler) appendKeyValuePair(buf []byte, a slog.Attr) []byte {
+	if h.opts.Colored {
+		if a.Key == "err" {
+			return fmt.Appendf(buf, "%s%s=%v%s ", BrightRed, a.Key, a.Value.String(), Reset)
+		}
+		return fmt.Appendf(buf, "%s%s=%s%s%s%s ", WhiteDim, a.Key, Reset, White, a.Value.String(), Reset)
+	}
+	return fmt.Appendf(buf, "%s=%v ", a.Key, a.Value.String())
+}
+
+func free(b *[]byte) {
+	if cap(*b) <= maxBufferSize {
+		*b = (*b)[:0]
+		bufPool.Put(b)
+	}
+}
+
+func source(r slog.Record) *slog.Source {
+	fs := runtime.CallersFrames([]uintptr{r.PC})
+	f, _ := fs.Next()
+	return &slog.Source{
+		Function: f.Function,
+		File:     f.File,
+		Line:     f.Line,
+	}
+}