dead letters encountered and timed out replies

[Nicola Piccinini]

hi all,

my understanding is that when I have:

actorRef ? "hi"

and the future times out, the reply eventually sent back from actorRef goes to dead-letters.

That is fine but the log is "polluted" with messages about "dead letters encountered" related to those replies.

Is there a way to filter out only this kind of messages from the log (but keep other "dead letters encountered")?

Thanks,

Nicola

[Akka Team]

Hi Nicola,

As far as I know not, there are only two configuration settings related to dead letters:

akka.log-dead-letters
akka.log-dead-letters-during-shutdown

but you don't have the ability to filter on different "kinds" of dead letters. You can subscribe though to dead letter events and handle them as you want, see here:

http://doc.akka.io/docs/akka/2.3.6/general/message-delivery-reliability.html#Dead_Letters

and here

http://doc.akka.io/docs/akka/2.3.6/general/message-delivery-reliability.html#How_do_I_Receive_Dead_Letters_

and even more information here:

http://doc.akka.io/docs/akka/2.3.6/scala/event-bus.html#Event_Stream

-Endre

 

Thanks,

Nicola

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[Nicola Piccinini]

thanks Endre for the pointers but I am still out of luck.

The DeadLetter objects I see when I subscribe to the event stream
have already "dead-letter" as recipient, so it is impossible to
determine if they were a reply to a timed out "ask".

I tried to define a sort of conditional reply, in order to reply to
the ask only if the sending actor is not terminated but it did not
work.

If I am not able to filter out this kind of errors from the
dead-letter log, it is useless to look at it.

Best regards,
Nicola

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[Akka Team]

Hi Nicola,

The DeadLetter objects I see when I subscribe  to the event stream
have already "dead-letter" as recipient, so it is impossible to
determine if they were a reply to a timed out "ask".
I tried to define a sort of conditional reply, in order to reply to
the ask only if the sending actor is not terminated but it did not
work.

Right, this will be racy anyway as you're working with a concurrent system here so there could be races between

you checking if someone is alive and it dying before it gets the message delivered.

 

If I am not able to filter out this kind of errors from the dead-letter log, it is useless to look at it.

Dead letters are useful to look at then you send things to wrong / dead actors and you didn't notice for example.

In the ask-late-reply case at least you'll get to see that there was a response like that, while not super precise it's still a bit helpful.

Sorry we don't have a better solution here.

Future wise we've been thinking about adding some kinds of tracing, which would make these kinds of things easier to detect.

-- 

Konrad

[Nicola Piccinini]

>> If I am not able to filter out this kind of errors from the dead-letter
>> log, it is useless to look at it.
>
> Dead letters are useful to look at then you send things to wrong / dead
> actors and you didn't notice for example.

yes, in fact it is potentially very useful and I would like to check
it to be sure that the system is working properly but this is no
longer possible if it gets flooded by "late ask replies".

> Sorry we don't have a better solution here.
> Future wise we've been thinking about adding some kinds of tracing, which
> would make these kinds of things easier to detect.

thank you for taking that into consideration, best regards,

Nicola