Custom logger

Author: fileformat

internal/Logger.go

@@ -0,0 +1,75 @@
+package internal
+
+import (
+	"context"
+	"log/slog"
+	"os"
+	"strconv"
+	"strings"
+)
+
+var Logger = initLogger()
+var LogLevel = slog.LevelInfo
+
+// level=Trace is for stuff that should not be logged in production, either because it's too verbose or because it contains sensitive information.
+
+func initLogger() *LoggerWithTrace {
+
+	logLevel := os.Getenv("LOG_LEVEL")
+	var err error
+	if logLevel != "" {
+		ilvl, atoiErr := strconv.Atoi(logLevel)
+		if atoiErr == nil {
+			LogLevel = slog.Level(ilvl)
+		} else if strings.ToLower(logLevel) == "trace" {
+			LogLevel = -8
+		} else {
+			err = LogLevel.UnmarshalText([]byte(logLevel))
+			if err != nil {
+				LogLevel = slog.LevelInfo
+			}
+		}
+	}
+
+	// get log format from the environment
+	logFormat := os.Getenv("LOG_FORMAT")
+	var handler slog.Handler
+	switch logFormat {
+	case "json":
+		handler = slog.NewJSONHandler(os.Stderr, &slog.HandlerOptions{
+			Level:     LogLevel,
+			AddSource: true,
+		})
+	default:
+		handler = slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{
+			Level:     LogLevel,
+			AddSource: true,
+		})
+	}
+
+	logger := slog.New(handler)
+	slog.SetDefault(logger)
+
+	if err != nil {
+		slog.Error("unable to set log level", "level", LogLevel, "error", err)
+	} else {
+		slog.Debug("log level set", "level", LogLevel)
+	}
+
+	return &LoggerWithTrace{Logger: logger}
+}
+
+// LoggerWithTrace is a wrapper around slog.Logger that adds a Trace method.
+type LoggerWithTrace struct {
+	*slog.Logger
+}
+
+// Trace logs a message at the trace level.
+func (l *LoggerWithTrace) Trace(msg string, keyvals ...interface{}) {
+	l.Log(context.Background(), slog.Level(-8), msg, keyvals...)
+}
+
+// WithTrace returns the LoggerWithTrace instance.
+func (l *LoggerWithTrace) WithTrace() *LoggerWithTrace {
+	return l
+}