When request is aborted, cancel event is not propagated to downstream services.

[joaobologna]

When a request is aborted by the client, spring-cloud-gateway is aware of it by Subscription.cancel(). Adding a filter can easily comprove this behavior, where

override fun apply(config: Config?): GatewayFilter {
    return GatewayFilter { exchange, chain ->
        chain.filter(exchange)
                .log()
                .doOnCancel { log.info { "ABORTED" } }
    }
}

when a request is canceled, generates

2020-06-01 11:20:03.824 INFO t=boundedElastic-7 reactor.Mono.LiftFuseable.1 - | onSubscribe([Fuseable] ScopePassingSpanSubscriber)
2020-06-01 11:20:03.824 INFO t=boundedElastic-7 reactor.Mono.LiftFuseable.1 - | request(unbounded)
2020-06-01 11:20:04.639 INFO t=reactor-http-epoll-2 p.s.g.s.filter.GatewayLogFilter - ABORTED
2020-06-01 11:20:04.640 INFO t=reactor-http-epoll-2 reactor.Mono.LiftFuseable.1 - | cancel()

But if it was routed to a downstream service, SCG does not notifies the service. I don't know if this should be default but, at least, should be configurable.

Looking at NettyRoutingFilter, only when a response is recieved, CLIENT_RESPONSE_CONN_ATTR is set as an exchange attribute, later used in NettyWriteResponseFilter#(cleanup) to dispose the call using doOnCancel event.

Version:

• spring-cloud-gatway: 2.2.1

[jovan-fernandes]

I also came across this situation mainly with mobile browsers when they go to the background and a request is in progress..

[spencergibb]

@joaobologna are you asking for logging in doOnCancel()?

[joaobologna]

@spencergibb no, I would like to notify the downstream service that the request was canceled. As for now, the service processing the routed request will compute it even though it was canceled by the client.

[spencergibb]

how would you do such a thing?

[joaobologna]

if the connection used on NettyRoutingFilter was disposed, wouldn't that solve the trick?

[spencergibb]

@violetagg does this make sense?