Add support for arbitrary numeric log level strings

Support numeric log level ranges defined by slog library.

Signed-off-by: Derek McGowan <derek@mcg.dev>

Author: dmcgowan

context.go

@@ -40,6 +40,8 @@ package log
 import (
 	"context"
 	"fmt"
+	"strconv"
+	"strings"
 
 	"github.com/sirupsen/logrus"
 )
@@ -120,8 +122,19 @@ const (
 //   - "error" ([ErrorLevel])
 //   - "fatal" ([FatalLevel])
 //   - "panic" ([PanicLevel])
+//
+// In addition, a numeric value can be provided using
+// the level range defined by Go's slog library:
+//
+//   - -8: trace
+//   - -4: debug
+//   - 0: info
+//   - 4: warn
+//   - 8: error
+//   - 10: fatal
+//   - 12: panic
 func SetLevel(level string) error {
-	lvl, err := logrus.ParseLevel(level)
+	lvl, err := parseLevel(level)
 	if err != nil {
 		return err
 	}
@@ -130,6 +143,50 @@ func SetLevel(level string) error {
 	return nil
 }
 
+func parseLevel(level string) (Level, error) {
+	switch strings.ToLower(level) {
+	case "trace":
+		return TraceLevel, nil
+	case "debug":
+		return DebugLevel, nil
+	case "info":
+		return InfoLevel, nil
+	case "warn", "warning":
+		return WarnLevel, nil
+	case "error":
+		return ErrorLevel, nil
+	case "fatal":
+		return FatalLevel, nil
+	case "panic":
+		return PanicLevel, nil
+	}
+
+	// Default to parsing as numeric level
+	if v, err := strconv.Atoi(level); err == nil {
+		return numericLevel(v), nil
+	}
+	return InfoLevel, fmt.Errorf("unknown log level: %s", level)
+}
+
+// numericLevel returns the logrus level for the given integer value,
+// choosing the nearest level without going above the given value.
+func numericLevel(v int) Level {
+	if v <= -8 {
+		return TraceLevel
+	} else if v <= -4 {
+		return DebugLevel
+	} else if v <= 0 {
+		return InfoLevel
+	} else if v <= 4 {
+		return WarnLevel
+	} else if v <= 8 {
+		return ErrorLevel
+	} else if v <= 10 {
+		return FatalLevel
+	}
+	return PanicLevel
+}
+
 // GetLevel returns the current log level.
 func GetLevel() Level {
 	return L.Logger.GetLevel()

context_test.go

@@ -38,6 +38,63 @@ func TestLoggerContext(t *testing.T) {
 	}
 }
 
+func TestSetLevel(t *testing.T) {
+	for _, tc := range []struct {
+		input    string
+		expected Level
+	}{
+		// Named levels
+		{input: "trace", expected: TraceLevel},
+		{input: "debug", expected: DebugLevel},
+		{input: "info", expected: InfoLevel},
+		{input: "warn", expected: WarnLevel},
+		{input: "warning", expected: WarnLevel},
+		{input: "error", expected: ErrorLevel},
+		{input: "fatal", expected: FatalLevel},
+		{input: "panic", expected: PanicLevel},
+		{input: "INFO", expected: InfoLevel},
+		{input: "DEBUG", expected: DebugLevel},
+
+		// Exact slog integer levels
+		{input: "-8", expected: TraceLevel},
+		{input: "-4", expected: DebugLevel},
+		{input: "0", expected: InfoLevel},
+		{input: "4", expected: WarnLevel},
+		{input: "8", expected: ErrorLevel},
+		{input: "10", expected: FatalLevel},
+		{input: "12", expected: PanicLevel},
+
+		// Nearest numeric levels (without going above)
+		{input: "-10", expected: TraceLevel},
+		{input: "-6", expected: DebugLevel},
+		{input: "-5", expected: DebugLevel},
+		{input: "-2", expected: InfoLevel},
+		{input: "1", expected: WarnLevel},
+		{input: "2", expected: WarnLevel},
+		{input: "3", expected: WarnLevel},
+		{input: "6", expected: ErrorLevel},
+		{input: "7", expected: ErrorLevel},
+		{input: "9", expected: FatalLevel},
+		{input: "11", expected: PanicLevel},
+		{input: "13", expected: PanicLevel},
+		{input: "100", expected: PanicLevel},
+
+		// Unparseable defaults to panic
+		{input: "bogus", expected: PanicLevel},
+		{input: "", expected: PanicLevel},
+	} {
+		t.Run(tc.input, func(t *testing.T) {
+			err := SetLevel(tc.input)
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+			if actual := GetLevel(); actual != tc.expected {
+				t.Errorf("expected level %v, got %v", tc.expected, actual)
+			}
+		})
+	}
+}
+
 func TestCompat(t *testing.T) {
 	expected := Fields{
 		"hello1": "world1",