java.lang.IllegalStateException: block()/blockFirst()/blockLast() are blocking

エラーログ:

	reactor.core.Exceptions$BubblingException: java.lang.IllegalStateException: block()/blockFirst()/blockLast() are blocking, which is not supported in thread reactor-http-epoll-4
	at reactor.core.Exceptions.bubble(Exceptions.java:170)
	at reactor.core.publisher.Operators.onErrorDropped(Operators.java:521)
	at reactor.core.publisher.FluxDoFinally$DoFinallySubscriber.runFinally(FluxDoFinally.java:159)
	at reactor.core.publisher.FluxDoFinally$DoFinallySubscriber.cancel(FluxDoFinally.java:145)
	at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.drainLoop(Operators.java:2051)
...

分析

リクエストがアクティブに切断されたため、nettyはchannel処理を取得できず、異常を投げ出し、nginx状態は499と表示された.
処理方式logbackフィルタ部分ログ出力
Nettyソース修正