build: add styling option for console logger

This will only be available when the dev build tag is set

build/config.go

@@ -1,3 +1,6 @@
+//go:build !dev
+// +build !dev
+
 package build
 
 import "github.com/btcsuite/btclog/v2"

build/config_dev.go

@@ -0,0 +1,137 @@
+//go:build dev
+// +build dev
+
+package build
+
+import (
+	"fmt"
+	"strings"
+
+	btclogv1 "github.com/btcsuite/btclog"
+	"github.com/btcsuite/btclog/v2"
+)
+
+const (
+	resetSeq = "0"
+	boldSeq  = "1"
+	faintSeq = "2"
+	esc      = '\x1b'
+	csi      = string(esc) + "["
+)
+
+// LogConfig holds logging configuration options.
+//
+//nolint:lll
+type LogConfig struct {
+	Console *consoleLoggerCfg `group:"console" namespace:"console" description:"The logger writing to stdout and stderr."`
+	File    *LoggerConfig     `group:"file" namespace:"file" description:"The logger writing to LND's standard log file."`
+}
+
+// LoggerConfig holds options for a particular logger.
+//
+//nolint:lll
+type LoggerConfig struct {
+	Disable      bool `long:"disable" description:"Disable this logger."`
+	NoTimestamps bool `long:"no-timestamps" description:"Omit timestamps from log lines."`
+}
+
+// HandlerOptions returns the set of btclog.HandlerOptions that the state of the
+// config struct translates to.
+func (cfg *LoggerConfig) HandlerOptions() []btclog.HandlerOption {
+	var opts []btclog.HandlerOption
+	if cfg.NoTimestamps {
+		opts = append(opts, btclog.WithNoTimestamp())
+	}
+
+	return opts
+}
+
+// consoleLoggerCfg extends the LoggerConfig struct by adding a Color option
+// which is only available for a console logger.
+//
+//nolint:lll
+type consoleLoggerCfg struct {
+	LoggerConfig
+	Style bool `long:"style" description:"If set, the output will be styled with color and fonts"`
+}
+
+// HandlerOptions returns the set of btclog.HandlerOptions that the state of the
+// config struct translates to.
+func (cfg *consoleLoggerCfg) HandlerOptions() []btclog.HandlerOption {
+	opts := cfg.LoggerConfig.HandlerOptions()
+
+	if !cfg.Style {
+		return opts
+	}
+
+	return append(
+		opts, btclog.WithStyledLevel(
+			func(l btclogv1.Level) string {
+				return styleString(
+					fmt.Sprintf("[%s]", l),
+					boldSeq,
+					string(ansiColoSeq(l)),
+				)
+			},
+		),
+		btclog.WithStyledCallSite(
+			func(file string, line int) string {
+				str := fmt.Sprintf("%s:%d", file, line)
+
+				return styleString(str, faintSeq)
+			},
+		),
+		btclog.WithStyledKeys(func(key string) string {
+			return styleString(key, faintSeq)
+		}),
+	)
+}
+
+// DefaultLogConfig returns the default logging config options.
+func DefaultLogConfig() *LogConfig {
+	return &LogConfig{
+		Console: &consoleLoggerCfg{},
+		File:    &LoggerConfig{},
+	}
+}
+
+func styleString(s string, styles ...string) string {
+	if len(styles) == 0 {
+		return s
+	}
+
+	seq := strings.Join(styles, ";")
+	if seq == "" {
+		return s
+	}
+
+	return fmt.Sprintf("%s%sm%s%sm", csi, seq, s, csi+resetSeq)
+}
+
+type ansiColorSeq string
+
+const (
+	ansiColorSeqDarkTeal  ansiColorSeq = "38;5;30"
+	ansiColorSeqDarkBlue  ansiColorSeq = "38;5;63"
+	ansiColorSeqLightBlue ansiColorSeq = "38;5;86"
+	ansiColorSeqYellow    ansiColorSeq = "38;5;192"
+	ansiColorSeqRed       ansiColorSeq = "38;5;204"
+	ansiColorSeqPink      ansiColorSeq = "38;5;134"
+)
+
+func ansiColoSeq(l btclogv1.Level) ansiColorSeq {
+	switch l {
+	case btclog.LevelTrace:
+		return ansiColorSeqDarkTeal
+	case btclog.LevelDebug:
+		return ansiColorSeqDarkBlue
+	case btclog.LevelWarn:
+		return ansiColorSeqYellow
+	case btclog.LevelError:
+		return ansiColorSeqRed
+	case btclog.LevelCritical:
+		return ansiColorSeqPink
+	default:
+		return ansiColorSeqLightBlue
+	}
+}