SentryWebFilter and SentryWebTracingFilter

[sleep-dev]

Hello team.

In the middle of developing webflux user identification, I found something that I cannot understand.

In the SentryWebFilter, code like

chain.filter(exchange).doFinally( __ -> { 
    requestHub.popScope()
...
})
.doFirst {
...
    requestHub.pushScope()
...
}

and in the SentryWebTracingFilter

chain.filter(exchange).doFinally( __ -> {
    ...
    transaction.finish()
})

Most of time in my computer, transaction.finish() is run after hub.popScope(). so even though I change the scope information before popScope(), it doesn't apply when transaction.finish()

I made a filter to change the scope information, but it doesn't affect. and I think above things are reason.

I wrote code like below

class CustomSentryFilter: WebFilter {
    override fun filter(exchange: ServerWebExchange, chain: WebFilterChain): Mono<Void> {
        val hub = exchange.attributes.getOrDefault(SentryWebFilter.SENTRY_HUB_KEY, null) as IHub
        hub.configureScope { scope ->
           // something change outside of Mono flow
        }

        return Mono.just(1)
            .doOnNext { 
                hub.configureScope { scope ->
                   //something change in the middle
                }
            }
            .then(chain.filter(exchange)
            .doFirst {
                hub.configureScope { scope ->
                   //something change on first
                }
            }
            .doFinally {
               hub.configureScope { scope -> 
                  //something change on finally
               }
            }
    }
}

Sometimes, SentryWebFilter doFinally run after SentryWebTracingFilter's one, in that time it give me result what i want. but in the most of time it doesn't.

Is there something that I misunderstand? How can I fix it?

[adinauer]

Hello @sleep-dev, can you confirm the order of filters is correct and your CustomSentryFilter is invoked after SentryWebFilter / SentryWebTracingFilter?

[sleep-dev]

Yup, I debugged and result shows CustomSentryFilter run after SentryWebFilter and WebTracingFilter.

[sleep-dev]

I found that SentryWebFilter uses Ordered.HIGHEST_PRECEDENCE and SentryWebTracingFilter uses Ordered.HIGHEST_PRECEDENCE+1
I tested CustomSentryFilter on both 0 and Ordered.HIGHEST_PRECEDENCE+2 and both show same result.

I use
spring-boot 2.7.11
sentry 6.18.1

(added)

If I set the CustomSentryFilter order between SentryWebFilter and SentryWebTracingFilter then the doFinally on CustomSentryFilter affect to result.

Is that right way?

[adinauer]

If I set the CustomSentryFilter order between SentryWebFilter and SentryWebTracingFilter then the doFinally on CustomSentryFilter affect to result.

Hmm this surprises me.

Hub.popScope being executed before transaction.finish() sounds like a bug to me. Not sure if this was introduced recently or if it's been there for a while. I'll investigate.

As a workaround, can you please try to retrieve the current transaction in your CustomSentryFilter and manipulate the transaction directly?

[adinauer]

I've created #2700 to track the bug.