[akka-user] Re: Cassandra Journal < v2.0.3?

Thanks Mathew, We have been trying to do the same and did a quick testing by making the below changes 1. Changed the datastax cassandra-driver-core to version 2.0.1 from 2.0.3. Version 2.0.1 supports 1.2+ ( we user C* 1.2.x.x) that works with CQL3 2. Got rid of the "IF NOT EXISTS" clause ( via

Re: [akka-user] Using stash with become

Luis, As an actor only handles one message at a time, the order of `unstashAll` and `context.become` doesn't matter at all: Both happen while processing the current message which means that no other message gets processed until both methods (and the rest of the current behavior) have been execu

Re: [akka-user] Improving Akka Persistence wrt CQRS/ES/DDD

On 19.08.14 21:57, Greg Young wrote: please forgive the typo. It still adds a ton of complexity that is unnecessary for the vast number of systems. I don't see that. The complexity should only be on plugin providers, not application code (see also the research paper I linked in a previous

Re: [akka-user] modifying log level at run-time

or: defsetLogLevel(level: LogLevel ): Unit Change log level: default loggers (i.e. from configuration file) are subscribed/unsubscribed as necessary so that they liste

Re: [akka-user] modifying log level at run-time

Or, if you just want a reloadable runtime, you can tell Logback to watch for changes to the logging file using autoScan: http://logback.qos.ch/manual/configuration.html#autoScan Will Sargent Consultant, Professional Services Typesafe , the company behind Play Framework

Re: [akka-user] modifying log level at run-time

Yes, you can use SLF4JLogger, then cast to Logback and change the log level there. http://stackoverflow.com/a/3838108/5266 Will Sargent Consultant, Professional Services Typesafe , the company behind Play Framework , Akka and Sca

Re: [akka-user] Improving Akka Persistence wrt CQRS/ES/DDD

please forgive the typo. It still adds a ton of complexity that is unnecessary for the vast number of systems. We support it in event store but most don't use it. On Tuesday, August 19, 2014 11:08:14 AM UTC-4, Martin Krasser wrote: > > > On 19.08.14 16:27, Greg Young wrote: > > I am not respo

[akka-user] Re: Cassandra Journal < v2.0.3?

Hi - no we haven't implemented this yet... we wound up getting sidetracked by some other priorities. But we are going to need to implement this at some point. It's been a bit since I've looked into the details but as I remember there were 2 key changes needed for C* 1.2: 1. C* 2.0 introduce

[akka-user] modifying log level at run-time

Hi, I know Akka's configuration does not get reloaded at run-time (see here ). It is however quite a common use case for logger settings to be re-loadable at run-time. Is there any way to achieve this? -- >>

[akka-user] Re: WebSocket + AKKA + Redis pub/sub

I've never used it in production but wy back I built a proof-of-concept based on one of the Play Framework sample apps using Redis pub/sub to feed a WebSocket based chat room. https://github.com/ryantanner/websocketchat-redis It does extremely little, really just round-trips messages across

Re: [akka-user] akka app design questions

On Tue, Aug 19, 2014 at 4:51 AM, Fej wrote: > I'm trying to learn akka and need a clarification how to design an > application. Lets imagine simple HTTP CRUD app, which handles some > documents stored in mongodb. For each of this operations I'd need at least > one actor processing request, fetchi

[akka-user] Akka shell?

A bit off topic, but I hope the Typesafe gurus are ahead of us on this :-) Has anyone ever thought of a UNIX "shell" build on the Scala REPL which has akka on the backend? As we are moving to distributed clusters, it seems to me that a UNIX shell with the REPL and maybe the Akka microker

Re: [akka-user] Akka FSM and Akk persistence with Java (8)

Hi Barak, It’s currently not possible to use FSM with PersistentActors. We do want to provide this before persistence goes stable, here’s the ticket for tracking it: https://github.com/akka/akka/issues/15279 I was already playing around with implementing it, but sadly it requires a bit more work

[akka-user] Akka FSM and Akk persistence with Java (8)

Hi, We have just started to build our new application with Akka using java 8. We started by using the FSM actor but when we read about the persistent actors we wanted to use them as well. I saw that in the Scala documentation of the persistence module there is a reference on how to combine the

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

On 19.08.14 18:48, delasoul wrote: As I am no Spark expert - will it be used only as kind of messaging(streaming) middleware to sync write and read store or also to somehow change/merge/ filter the events it gets/pulls from the write store usually, to process (transform/aggregate/filter/...)

[akka-user] Using stash with become

Hi all, I'm working on implementing retry functionality in one of my actor's that will retry writing a message to RabbitMQ if the original write fails. This looks something like this: private String retryMessage; private void processMessage(String message) { try { writer.write(mess

Re: [akka-user] Improving Akka Persistence wrt CQRS/ES/DDD

On Tuesday, 19 August 2014 21:14:17 UTC+8, rkuhn wrote: > > > 18 aug 2014 kl. 18:01 skrev Ashley Aitken > >: > > I believe Akka needs to allow actors to: > > > (i) persist events with as much information as efficiently possible on the > write side to allow the store to facilitate the read side

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

As I am no Spark expert - will it be used only as kind of messaging(streaming) middleware to sync write and read store or also to somehow change/merge/ filter the events it gets/pulls from the write store or is this all done via the plugin for PersistentViews? (I guess it has to be like this, ot

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

Ok thanks, what confused me was: "a simple way to replicate events to the read side" - which I misunderstood for sending events, but you meant smthg. else. If a PersistentView is only involved in writing the ReadModel, is it not harder to achieve a consistent read model (have to make sure that t

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

On 19.08.14 17:41, Ashley Aitken wrote: On Tuesday, 19 August 2014 19:33:55 UTC+8, Martin Krasser wrote: If so, it sounds like a great solution but why would that require an extension to the Akka Persistence design/API? Because transformed/joined/... event streams in backend st

Re: [akka-user] WebSocket + AKKA + Redis pub/sub

This seems like a fairly common pattern/problem domain that people will be facing when they want to incorporate real-time updates on websites. Is there anything open source that can help guide me on how to implement this? I was thinking of using redis also but rabbitmq would be very similiar j

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

On Tuesday, 19 August 2014 19:33:55 UTC+8, Martin Krasser wrote: > > If so, it sounds like a great solution but why would that require an > extension to the Akka Persistence design/API? > > > Because transformed/joined/... event streams in backend store on the read > side must be consumable b

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

On Tue, Aug 19, 2014 at 5:07 PM, delasoul wrote: > Then the PersistentView is not used as a "middle-man" to replicate events > to the read side, but it is the read side(meaning if a client sends a query > a PersistentView creates the response)? > That's how I understood PersistentViews until now

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

Then the PersistentView is not used as a "middle-man" to replicate events to the read side, but it is the read side(meaning if a client sends a query a PersistentView creates the response)? That's how I understood PersistentViews until now - but maybe that was wrong, so I' am asking... thank's

[akka-user] Re: Event Stores for Akka Persistence for CQRS?

So I will mention some of the advantages of event store. 1) You can actually repartition etc your events for read models (functionality exists today) 2) As far as I know we are actually older than kafka 3) We support many things kafka does not (such as competing consumers on streams as well as c

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

On Tuesday, August 19, 2014 9:44:10 AM UTC-4, rkuhn wrote: > > > 19 aug 2014 kl. 15:39 skrev Juan José Vázquez Delgado >: > > Hi guys, really interesting thread. However, it follows from this > discussion that Akka Persistence is not currently 100% ready for a full > CRQS/ES implementation. A

Re: [akka-user] Improving Akka Persistence wrt CQRS/ES/DDD

I am not responding to this one post just a reply towards the end and will discuss a few posts from earlier. To start I have to agree with some of the posters that premature scaling can cause many issues. This actually reminds me of the CQRS journey which people mentioned earlier. One of the ma

Re: [akka-user] [akka-stream] : Streaming large file from 1 server to 1 client

On Tue, Aug 19, 2014 at 4:08 PM, Xavier Bucchiotty wrote: > Hello HakKers, > > I need to transfer larges files (~GB) between 2 distants VM. I first used > akka.io module which works great. > I currently take a look a akka-stream-experimental module to benefit from > precious asynchronous backpres

[akka-user] [akka-stream] : Streaming large file from 1 server to 1 client

Hello HakKers, I need to transfer larges files (~GB) between 2 distants VM. I first used akka.io module which works great. I currently take a look a akka-stream-experimental module to benefit from precious asynchronous backpressure. But when I create a Flow from a Stream[ByteString], it keeps a

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

On Tue, Aug 19, 2014 at 2:33 PM, delasoul wrote: > "and therefore we provide PersistentView as a simple way to replicate > events to the read side, and then a de-normalized representation can be > stored..." > > If I understand this right, this means: > PersistenActor persists event > PersistentV

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

19 aug 2014 kl. 15:39 skrev Juan José Vázquez Delgado : > Hi guys, really interesting thread. However, it follows from this discussion > that Akka Persistence is not currently 100% ready for a full CRQS/ES > implementation. A little bit frustrating but, to be honest, it's true that > it's stil

Re: [akka-user] Improving Akka Persistence wrt CQRS/ES/DDD

So how does one handle combining events from different streams- a global sequence number is the most straightforward. Also, not everything needs to scale on the write side to that degree. On Aug 19, 2014 9:24 AM, "√iktor Ҡlang" wrote: > The decision if scale is needed cannot be implicit, as then

[akka-user] Re: Event Stores for Akka Persistence for CQRS?

Hi guys, really interesting thread. However, it follows from this discussion that Akka Persistence is not currently 100% ready for a full CRQS/ES implementation. A little bit frustrating but, to be honest, it's true that it's still an experimental feature. As users, we're assuming this. Anyway,

Re: [akka-user] Improving Akka Persistence wrt CQRS/ES/DDD

The decision if scale is needed cannot be implicit, as then you are luring people into the non-scalable world and when they find out then it is too late. On Tue, Aug 19, 2014 at 3:20 PM, Roland Kuhn wrote: > > 19 aug 2014 kl. 14:57 skrev Gary Malouf : > > For CQRS specifically, a lot of what pe

Re: [akka-user] Improving Akka Persistence wrt CQRS/ES/DDD

19 aug 2014 kl. 14:57 skrev Gary Malouf : > For CQRS specifically, a lot of what people call scalability is in it's > ability to easily model multiple read views to make queries very fast off the > same event data. > > In the cases where a true global ordering is truly necessary, one often doe

Re: [akka-user] Improving Akka Persistence wrt CQRS/ES/DDD

19 aug 2014 kl. 07:18 skrev Greg Young : > everything you list here is available today via akka.persistence + event > store adapter & a durable subscription (akka event store client) on the read > model side. This sounds like the best candidate for a way forward at this point. “Durable subscr

Re: [akka-user] Improving Akka Persistence wrt CQRS/ES/DDD

18 aug 2014 kl. 18:01 skrev Ashley Aitken : > Hi Roland (and everyone), > > Welcome back Roland - I hope you had a great vacation. > > Thank you for your post. > > > Here’s my response summary: > > I believe Akka needs to allow actors to: > > (i) persist events with as much information as

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

On 19.08.14 14:37, Roland Kuhn wrote: 19 aug 2014 kl. 13:49 skrev Patrik Nordwall >: On Tue, Aug 19, 2014 at 1:46 PM, Martin Krasser mailto:krass...@googlemail.com>> wrote: On 19.08.14 13:40, Patrik Nordwall wrote: On Tue, Aug 19, 2014 at 1:35

Re: [akka-user] Improving Akka Persistence wrt CQRS/ES/DDD

For CQRS specifically, a lot of what people call scalability is in it's ability to easily model multiple read views to make queries very fast off the same event data. In the cases where a true global ordering is truly necessary, one often does not need to handle hundreds of thousands of writes per

Re: [akka-user] Improving Akka Persistence wrt CQRS/ES/DDD

18 aug 2014 kl. 16:49 skrev Patrik Nordwall : > On Mon, Aug 18, 2014 at 3:38 PM, Roland Kuhn wrote: > > 18 aug 2014 kl. 10:27 skrev Patrik Nordwall : > >> Hi Roland, >> >> A few more questions for clarification... >> >> >> On Sat, Aug 16, 2014 at 10:11 PM, Vaughn Vernon >> wrote: >> > >

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

19 aug 2014 kl. 13:49 skrev Patrik Nordwall : > On Tue, Aug 19, 2014 at 1:46 PM, Martin Krasser > wrote: > > On 19.08.14 13:40, Patrik Nordwall wrote: >> >> >> >> On Tue, Aug 19, 2014 at 1:35 PM, Martin Krasser >> wrote: >> >> On 19.08.14 13:00, Roland Kuhn wrote: >>> >>> 19 aug 2014 kl

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

"and therefore we provide PersistentView as a simple way to replicate events to the read side, and then a de-normalized representation can be stored..." If I understand this right, this means: PersistenActor persists event PersistentView queries EventStore e.g.: every second and forwards new ev

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

On Tue, Aug 19, 2014 at 1:46 PM, Martin Krasser wrote: > > On 19.08.14 13:40, Patrik Nordwall wrote: > > > > > On Tue, Aug 19, 2014 at 1:35 PM, Martin Krasser > wrote: > >> >> On 19.08.14 13:00, Roland Kuhn wrote: >> >> >> 19 aug 2014 kl. 11:28 skrev Ashley Aitken : >> >> >> >> On Tuesday, 19 A

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

On 19.08.14 13:40, Patrik Nordwall wrote: On Tue, Aug 19, 2014 at 1:35 PM, Martin Krasser mailto:krass...@googlemail.com>> wrote: On 19.08.14 13:00, Roland Kuhn wrote: 19 aug 2014 kl. 11:28 skrev Ashley Aitken mailto:amait...@gmail.com>>: On Tuesday, 19 August 2014 16:53

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

On Tue, Aug 19, 2014 at 1:35 PM, Martin Krasser wrote: > > On 19.08.14 13:00, Roland Kuhn wrote: > > > 19 aug 2014 kl. 11:28 skrev Ashley Aitken : > > > > On Tuesday, 19 August 2014 16:53:46 UTC+8, Martin Krasser wrote: >> >> >> journal -> akka actor(s) -> read model datastore >> >> when I can d

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

On 19.08.14 13:00, Roland Kuhn wrote: 19 aug 2014 kl. 11:28 skrev Ashley Aitken >: On Tuesday, 19 August 2014 16:53:46 UTC+8, Martin Krasser wrote: journal -> akka actor(s) -> read model datastore when I can do this much more efficiently via journ

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

On 19.08.14 11:28, Ashley Aitken wrote: On Tuesday, 19 August 2014 16:53:46 UTC+8, Martin Krasser wrote: journal -> akka actor(s) -> read model datastore when I can do this much more efficiently via journal -> spark -> read model datastore directly, for example I am conf

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

19 aug 2014 kl. 11:28 skrev Ashley Aitken : > > > On Tuesday, 19 August 2014 16:53:46 UTC+8, Martin Krasser wrote: > > journal -> akka actor(s) -> read model datastore > > when I can do this much more efficiently via > > journal -> spark -> read model datastore > > directly, for example >

Re: [akka-user] Difference between ClusterReceptionistExtension(system).registerService and DistributedPubSubMediator.Put

I don't think that it's necessary to register it twice. You can just go with registerService. Right it they would just overwrite itself in the  DistributedPubSubMediator. B/ On 19 August 2014 at 06:51:55, JasonQ (quqingm...@gmail.com) wrote: Thanks Björn. So if I have an Actor which need recei

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

On Tuesday, 19 August 2014 16:53:46 UTC+8, Martin Krasser wrote: > > > journal -> akka actor(s) -> read model datastore > > when I can do this much more efficiently via > > journal -> spark -> read model datastore > > directly, for example > I am confused, are you suggesting that spark is ta

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

On Tuesday, 19 August 2014 14:51:42 UTC+8, Martin Krasser wrote: For full CQRS support, the discussions so far (in several other threads) > make the assumption that both write and read models are backed by the same > backend store (assuming read models are maintained by PersistentView actor,

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

On Tuesday, August 19, 2014 9:53:46 AM UTC+1, Martin Krasser wrote: I agree, but recent discussions were about how to join events from several > topics/streams that a PersistentView receives (e.g. all events of an > aggregate type or based on a user-defined join/query)... > I think the most re

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

On 19.08.14 10:00, Patrik Nordwall wrote: On Tue, Aug 19, 2014 at 8:51 AM, Martin Krasser mailto:krass...@googlemail.com>> wrote: Hi Ashley, thanks for bringing up these questions. Here are some general comments: as you already mentioned (in different words) akka-persiste

[akka-user] akka app design questions

Hello, I'm trying to learn akka and need a clarification how to design an application. Lets imagine simple HTTP CRUD app, which handles some documents stored in mongodb. For each of this operations I'd need at least one actor processing request, fetching db record and formatting the output? Wh

Re: [akka-user] Improving Akka Persistence wrt CQRS/ES/DDD

Thank you Greg, I hadn't thought of the Event Store JVM Client for the read model So I assume one would generally have a ConnectionActor for each custom event stream that is required to keep a particular query store up-to-date on the read side and

Re: [akka-user] Event Stores for Akka Persistence for CQRS?

On Tue, Aug 19, 2014 at 8:51 AM, Martin Krasser wrote: > Hi Ashley, > > thanks for bringing up these questions. Here are some general comments: > > as you already mentioned (in different words) akka-persistence is > currently optimized around write models rather than read models (= Q in > CQRS)