From ac0f02ebb6a82a430167e3abedd0869d866f0c26 Mon Sep 17 00:00:00 2001
From: Eser Ozvataf <eser@acikyazilim.com>
Date: Sun, 18 Aug 2024 06:28:30 +0300
Subject: [PATCH] feat(logfx): add PrettyMode to Config and implement new log
 handler

- Added PrettyMode field to Config struct with default true.
- Created new Handler struct in handler.go for flexible logging.
- Implemented NewHandler function.
- Modified RegisterLogger to use NewHandler.
- Updated replacerGenerator to conditionally handle prettyMode.
---
 pkg/bliss/logfx/config.go   |  5 ++-
 pkg/bliss/logfx/handler.go  | 76 +++++++++++++++++++++++++++++++++++++
 pkg/bliss/logfx/mod.go      | 10 +----
 pkg/bliss/logfx/replacer.go | 25 +++++++-----
 4 files changed, 95 insertions(+), 21 deletions(-)
 create mode 100644 pkg/bliss/logfx/handler.go

diff --git a/pkg/bliss/logfx/config.go b/pkg/bliss/logfx/config.go
index 270cd24..22d9ba3 100644
--- a/pkg/bliss/logfx/config.go
+++ b/pkg/bliss/logfx/config.go
@@ -1,6 +1,7 @@
 package logfx
 
 type Config struct {
-	Level     string `conf:"LEVEL"      default:"INFO"`
-	AddSource bool   `conf:"ADD_SOURCE" default:"false"`
+	Level      string `conf:"LEVEL"      default:"INFO"`
+	PrettyMode bool   `conf:"PRETTY"     default:"true"`
+	AddSource  bool   `conf:"ADD_SOURCE" default:"false"`
 }
diff --git a/pkg/bliss/logfx/handler.go b/pkg/bliss/logfx/handler.go
new file mode 100644
index 0000000..2feb249
--- /dev/null
+++ b/pkg/bliss/logfx/handler.go
@@ -0,0 +1,76 @@
+package logfx
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"log/slog"
+	"strings"
+)
+
+type Handler struct {
+	InnerHandler slog.Handler
+
+	writer io.Writer
+	config *Config
+}
+
+func NewHandler(w io.Writer, config *Config) (*Handler, error) {
+	var level slog.Level
+
+	err := level.UnmarshalText([]byte(config.Level))
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse log level: %w", err)
+	}
+
+	opts := &slog.HandlerOptions{
+		Level:       level,
+		ReplaceAttr: replacerGenerator(config.PrettyMode),
+		AddSource:   config.AddSource,
+	}
+
+	innerHandler := slog.NewJSONHandler(w, opts)
+
+	return &Handler{
+		InnerHandler: innerHandler,
+
+		writer: w,
+		config: config,
+	}, nil
+}
+
+func (h *Handler) Enabled(ctx context.Context, level slog.Level) bool {
+	return h.InnerHandler.Enabled(ctx, level)
+}
+
+func (h *Handler) Handle(ctx context.Context, rec slog.Record) error {
+	if h.config.PrettyMode {
+		out := strings.Builder{}
+
+		out.WriteString(rec.Time.Format("2006-01-02 15:04:05"))
+		out.WriteRune(' ')
+		out.WriteString(rec.Level.String())
+		out.WriteRune(' ')
+		out.WriteString(rec.Message)
+		out.WriteRune(' ')
+
+		_, err := io.WriteString(h.writer, out.String())
+		if err != nil {
+			return fmt.Errorf("failed to write log: %w", err)
+		}
+	}
+
+	return h.InnerHandler.Handle(ctx, rec)
+}
+
+func (h *Handler) WithAttrs(attrs []slog.Attr) slog.Handler {
+	return &Handler{
+		InnerHandler: h.InnerHandler.WithAttrs(attrs),
+	}
+}
+
+func (h *Handler) WithGroup(name string) slog.Handler {
+	return &Handler{
+		InnerHandler: h.InnerHandler.WithGroup(name),
+	}
+}
diff --git a/pkg/bliss/logfx/mod.go b/pkg/bliss/logfx/mod.go
index e34dd60..de09787 100644
--- a/pkg/bliss/logfx/mod.go
+++ b/pkg/bliss/logfx/mod.go
@@ -16,19 +16,11 @@ var Module = fx.Module(
 )
 
 func RegisterLogger(config *Config) (*slog.Logger, error) {
-	var level slog.Level
-
-	err := level.UnmarshalText([]byte(config.Level))
+	handler, err := NewHandler(os.Stderr, config)
 	if err != nil {
 		return nil, err
 	}
 
-	handler := slog.NewJSONHandler(os.Stderr, &slog.HandlerOptions{
-		Level:       level,
-		ReplaceAttr: replaceAttr,
-		AddSource:   config.AddSource,
-	})
-
 	logger := slog.New(handler)
 
 	slog.SetDefault(logger)
diff --git a/pkg/bliss/logfx/replacer.go b/pkg/bliss/logfx/replacer.go
index aec44c1..9339c12 100644
--- a/pkg/bliss/logfx/replacer.go
+++ b/pkg/bliss/logfx/replacer.go
@@ -15,18 +15,23 @@ type (
 	}
 )
 
-func replaceAttr(groups []string, attr slog.Attr) slog.Attr {
-	switch attr.Value.Kind() { //nolint:gocritic,wsl,exhaustive
-	// other cases
-
-	case slog.KindAny:
-		switch v := attr.Value.Any().(type) { //nolint:gocritic
-		case error:
-			attr.Value = fmtErr(v)
+func replacerGenerator(prettyMode bool) func([]string, slog.Attr) slog.Attr {
+	return func(groups []string, attr slog.Attr) slog.Attr {
+		if prettyMode {
+			if attr.Key == slog.TimeKey || attr.Key == slog.LevelKey || attr.Key == slog.MessageKey {
+				return slog.Attr{} //nolint:exhaustruct
+			}
+		}
+
+		if attr.Value.Kind() == slog.KindAny {
+			switch v := attr.Value.Any().(type) { //nolint:gocritic
+			case error:
+				attr.Value = fmtErr(v)
+			}
 		}
-	}
 
-	return attr
+		return attr
+	}
 }
 
 // fmtErr returns a slog.GroupValue with keys "msg" and "trace". If the error