better log level detection

level.go

@@ -83,7 +83,7 @@ func GuessLevel(line string) Level {
 			return r == ']' || r == ')' || r == ';' || r == '|' || r == ':' || r == ',' || r == '.'
 		})
 		for _, sf := range subfields {
-			sf = strings.TrimLeft(strings.ToLower(sf), "\"[('")
+			sf = strings.TrimLeft(strings.ToLower(sf), "\"[(<'")
 			sf = strings.TrimPrefix(sf, "level=")
 			if len(sf) < 4 {
 				continue

level_test.go

@@ -28,4 +28,5 @@ func TestGuessLevel(t *testing.T) {
 	assert.Equal(t, LevelError, GuessLevel(`2016-02-04T07:53:57.505612354Z" level=error msg="HTTP Error" err="No such image: -f" statusCode=404`))
 	assert.Equal(t, LevelDebug, GuessLevel(`[2020-06-25 17:35:37,609][DEBUG][action.search            ] [srv] [tweets-100][6]`))
 	assert.Equal(t, LevelError, GuessLevel(`[2023-10-12T09:56:53.393595+00:00] otel-php.ERROR: Export failure {"exception":"[object] (RuntimeException(code: 0): Export retry limit exceeded at /var/www/vendor/open-telemetry/sdk/Common/Export/Http/PsrTransport.php:114)","source":"OpenTelemetry\\Contrib\\Otlp\\SpanExporter"} []`))
+	assert.Equal(t, LevelWarning, GuessLevel(`2023.10.12 13:58:41.168802 [ 847 ] {} <Warning> TCPHandler: Using deprecated interserver protocol because the client is too old. Consider upgrading all nodes in cluster.`))
 }