akkadotnet/akka.net

Port of Akka actors for .NET

Tamir Dresher

@tamirdresher

The ActorSystem is running or a dedicated process

Sorry, meant to say: on a dedicated process

to11mtm

@to11mtm

@tamirdresher What about the call itself from the ASP net app to said actorsystem? how is that being done?

I know I've sen that at some point, trying to remember the how/why

Tamir Dresher

@tamirdresher

@to11mtm the ActorSystem is created when the application boots, and then upon the user action, it sends a message by using ActorSystem.ActorSelection(...)

to11mtm

@to11mtm

so typical Static actorsystem instantiated on application_start or similar?

Tamir Dresher

@tamirdresher

all the other messages that are sent are handled without a problem, but somehow, for some reason, this specific message causes the system to fault.

yes

exactly

to11mtm

@to11mtm

and -same- message works fine on on first try, fails on second?

Tamir Dresher

@tamirdresher

yes

and what i did find is that the message is being forwarded to another actor

unlike the others

to11mtm

@to11mtm

Interesting. one other question for a good picture; are you using Json or Wire for serialization?

Tamir Dresher

@tamirdresher

Wire

to11mtm

@to11mtm

I'd suggest MAYBE trying Json.NET, if only because once in a while I've had some issues with the current version of wire still has some edge cases that come up. I've seen errors like that when we send types over that Wire can't handle, but usually there's more stack trace to go with it. Can't say with much confidence given the amount of data I'm looking at, but it's easy to try right? =)

Tamir Dresher

@tamirdresher

right :-) i'll try that and then update. Thanks!

to11mtm

@to11mtm

NP. also curious about the 'forwarded to another actor' part

I'm bored on a sunday, may as well try to help somebody lol

Tamir Dresher

@tamirdresher

@to11mtm After changing to Json, everything works as expected

to11mtm

@to11mtm

YAY I WAS HELPFUL!

Tamir Dresher

@tamirdresher

Absolutely :-)

to11mtm

@to11mtm

You may want to place a ticket describing some of the issue (a test or even sample is immeasurably helpful) at https://github.com/akkadotnet/Hyperion/issues
Hyperion is the fork of Wire that will be used in further Akka releases, so that's the best place to have the issue tracked.

generally speaking however, Make sure anything you serialize is concrete-typed if you can (i.e. don't use Interfaces on messages, don't slam an arbitrary IEnumerable<> into an object field; instead do a ToList() on it first so there's a well known type on both ends)

(Because -that's- how I've seen that error before =D)

to11mtm

@to11mtm

Someone who knows more than me please confirm: There's an option in HOCON to serialize all messages. IFF I understand that correctly, that can help detect some serialization errors before they go across remoting and that can help troubleshoot, they will get published to the eventstream.
Keep in mind that you're going to have a perf penalty when doing that, so it's best used for trobleshooting scenarios.

Tamir Dresher

@tamirdresher

i think you mean this:

akka {
  actor {
    serialize-messages = on
  }
}

i'll check

to11mtm

@to11mtm

I think that's the one, you can see where it pushes errors to eventstream in the catch of this region: https://github.com/akkadotnet/akka.net/blob/dev/src/core/Akka/Actor/ActorCell.cs#L310

also note that if the serialization 'fails' things will still work local, so the eventstream is still the go to

Arjen Smits

@Danthar

@to11mtm you are correct about the serialize-messages option. That is a good way to detect serialization issues.

to11mtm @to11mtm is just glad he learned something from the groking

Arjen Smits

@Danthar

Nice post and explanation @Horusiath http://bartoszsypytkowski.com/optimizing-event-journals/

Bartosz Sypytkowski

@Horusiath

thx ;)

Arjen Smits

@Danthar

when we release the new implementation, we should put a link to that post in the release notes. It would help in letting people know what changed, why, and how it might impact them

Bartosz Sypytkowski

@Horusiath

When I wrote it, I've seen that it's more something that should be placed in a docs than inside blog post ;)

Arjen Smits

@Danthar

true :)

Arjen Smits

@Danthar

http://www.theregister.co.uk/2016/12/16/oracle_targets_java_users_non_compliance/

wauw

like... feels like the nail in the coffin for java

to11mtm

@to11mtm

@Horusiath Hey I was poking at some code thinking about akkadotnet/Hyperion#8 and noticed something that may be useful depending on how elegant MVP versus final solution needs to be...
But it looks like you can set readonly values on a struct if it was created by GetUninitializedObject: Sample here http://share.linqpad.net/499axc.linq

Bartosz Sypytkowski

@Horusiath

@to11mtm thx, but for some reason this doesn't work :)

once I'll find out why it doesn't work, maybe I'll find out how to make it work :)

Bartosz Sypytkowski

@Horusiath

the funny part is that we actually fill readonly fields in a the same way, you're using in you're using. But it throws

to11mtm

@to11mtm

HAHAHA wtf

Bartosz Sypytkowski

@Horusiath

I've fixed that, I understand what I changed, but I don't understand how was that supposed to change anything

Bartosz Sypytkowski

@Horusiath

basically, the code-gen first we were creating instance using Activator. That was returning a null, so the next we generated cast to a deserialized type. However later, for readonly fields, we were setting them with FieldInfo.SetValue(object, object), but that requires an object as a first param. So we generated code responsible for casting it back to object (but only for readonly fields). So struct created using activator → casted to its type → casted back to object, was causing an error.

what I've changed, was passing a direct reference to an object returned from activator (so we omitted all casts in this case). That worked.

to11mtm

@to11mtm

Interesting...

Andrew Young

@ayoung

YESSSS! http://www.hoconlint.com/

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