I'm trying to make a plugin that logs all calls an...

# ktor

[martmists]

I'm trying to make a plugin that logs all calls and exceptions, but the following snippet for my plugin seems to hang because I'm catching the exception, even if I'm re-throwing it later.

pipeline.intercept(ApplicationCallPipeline.Monitoring) {
    val start = Clock.System.now()
    val (exception, duration) = measureTimedValue {
        try {
            proceed()
            null
        } catch (e: Exception) {
            exceptionsChannel.send(e)
            e
        }
    }

    // ...

    if (exception != null) {
        throw exception
    }
}

Am I not supposed to call proceed, or should I catch exceptions some other way?

[Daniel Pitts]

If your channel is configured as rendezvous, it could suspend indefinitely if the receiver suspended or blocked on other things.

[Daniel Pitts]

For testing purposes, you might consider logging the exception when you catch it, logging that the channel send was successful, and logging that you’re about to re-throw.

[martmists]

The channel isn't relevant, just catching alone seems enough to halt the pipeline until the client disconnects.

[Aleksei Tirman [JB]]

On my machine, the interceptor works as expected if the code for sending to the channel is removed.

[martmists]

Strange, it was still happening for me when I'd removed it. Assuming it's the channel causing the problem, how would I still emit the exception to it?

[Aleksei Tirman [JB]]

You can try to increase the channel's buffer size for testing.

[martmists]

Where can I do that? I just create it with Channel<Exception>() which I'd assumed would grow as necessary similar to a List.

[Aleksei Tirman [JB]]

Channel<Exception>(10)

What do you mean by growing channel?

[Aleksei Tirman [JB]]

By default, it will suspend if more than one element is sent and hasn't been received on the other end.

[martmists]

Ah, in that case, what data type does kx.coroutines provide that acts like a MutableList, but with the ability to listen for new elements being appended?

[Aleksei Tirman [JB]]

I suggest asking it in the #C1CFAFJSK channel.