logging.Base()

Allow users to get access to the base logger *before* it is wrapped with the various levels.
This provides a single override point to filter or redirect all logging.

1 files changed, 33 insertions, 21 deletions

diff --git a/logging/logger.go b/logging/logger.go
index 87b5985..084bea0 100644
--- a/logging/logger.go
+++ b/logging/logger.go
@@ -2,6 +2,7 @@ package logging
 
 import (
 	"os"
+	"sync"
 
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
@@ -13,31 +14,42 @@ type Logger interface {
 	Log(keyvals ...any) error
 }
 
-// DefaultLoggers produces helpful base loggers for each level.
-//
-// They write logfmt to standard out, annotated with ANSI colors depending on the level.
-func DefaultLoggers() (debug, info, warn, error Logger) {
-	base := term.NewLogger(os.Stdout, log.NewLogfmtLogger, func(keyvals ...any) term.FgBgColor {
-		for i := 0; i < len(keyvals)-1; i += 2 {
-			if keyvals[i] != "level" {
-				continue
-			}
+var (
+	once       sync.Once
+	baselogger Logger
+)
 
-			switch keyvals[i+1] {
-			case level.DebugValue():
-				return term.FgBgColor{Fg: term.Gray}
-			case level.InfoValue():
-				return term.FgBgColor{Fg: term.Green}
-			case level.WarnValue():
-				return term.FgBgColor{Fg: term.Yellow}
-			case level.ErrorValue():
-				return term.FgBgColor{Fg: term.Red}
+func Base() Logger {
+	once.Do(func() {
+		base := term.NewLogger(os.Stdout, log.NewLogfmtLogger, func(keyvals ...any) term.FgBgColor {
+			for i := 0; i < len(keyvals)-1; i += 2 {
+				if keyvals[i] != "level" {
+					continue
+				}
+
+				switch keyvals[i+1] {
+				case level.DebugValue():
+					return term.FgBgColor{Fg: term.Gray}
+				case level.InfoValue():
+					return term.FgBgColor{Fg: term.Green}
+				case level.WarnValue():
+					return term.FgBgColor{Fg: term.Yellow}
+				case level.ErrorValue():
+					return term.FgBgColor{Fg: term.Red}
+				}
 			}
-		}
 
-		return term.FgBgColor{}
+			return term.FgBgColor{}
+		})
+		baselogger = log.NewSyncLogger(base)
 	})
-	base = log.NewSyncLogger(base)
+	return baselogger
+}
 
+// DefaultLoggers produces helpful base loggers for each level.
+//
+// They write logfmt to standard out, annotated with ANSI colors depending on the level.
+func DefaultLoggers() (debug, info, warn, error Logger) {
+	base := Base()
 	return level.Debug(base), level.Info(base), level.Warn(base), level.Error(base)
 }