On Sat, Feb 22, 2014 at 1:03 AM, Richard Rodseth <[email protected]> wrote:
> Another bit of feedback.
>
> Is there a way to inject the "listing" ActorRef into Post, or include it
> in a message, so that the Post code is not cluster-aware?
>
That is a very good suggestion. Add the listing: ActorRef as constructor
parameter, and specify it in the entryProps when starting the region.
ClusterSharding(system).start(
typeName = Post.shardName,
entryProps = Some(Props(classOf[Post],
ClusterSharding(system).shardRegion(AuthorListing.shardName))),
idExtractor = Post.idExtractor,
shardResolver = Post.shardResolver)
AuthorListing must be be started first.
Thank you for the feedback.
Regards,
Patrik
>
>
> On Fri, Feb 21, 2014 at 3:19 PM, Richard Rodseth <[email protected]>wrote:
>
>> Hi Patrik
>>
>> I should have just said "different". I'm not saying your design is wrong.
>> But you must admit that much of the design guidance that is offered for
>> actors says "think of an actor as a person". And certainly in a traditional
>> DDD app your aggregates aren't these autonomous things operating
>> concurrently. Now we have entities as actors, and with the clustered
>> sharding the "factory" as well as the supervision is all behind the scenes
>> (apparently). I'm confident it's going to be a great way to build apps -
>> just going through a learning process. Keep up the good work.
>>
>>
>> On Fri, Feb 21, 2014 at 2:54 PM, Patrik Nordwall <
>> [email protected]> wrote:
>>
>>> Hi,
>>>
>>> On Fri, Feb 21, 2014 at 10:42 PM, Richard Rodseth <[email protected]>wrote:
>>>
>>>> I have now read the sharding documentation, and this in the template.
>>>> Sorry I jumped the gun in my excitement :)
>>>> >>
>>>> To send messages to the identifier of the Post actor you need to send
>>>> them via the shardRegion actor, which can be retrieved via the
>>>> ClusterSharding extension. The sharding feature knows how to route the
>>>> message and it will on demand allocate the Post actors to cluster
>>>> nodes and create the actor instances. Exactly how this works under the hood
>>>> is described in the
>>>> documentation<http://doc.akka.io/docs/akka/2.3.0-RC4/contrib/cluster-sharding.html>
>>>> .
>>>> <<
>>>> It still feels a bit weird to think of actors as "entries" rather than
>>>> workers.
>>>>
>>>>
>>> Thanks for trying the new activator template [1].
>>>
>>> Weird? For me, an actor can be a consistency boundary with a meaningful
>>> identity and continuity through a life cycle, i.e. an Entity or Aggregate.
>>>
>>> Not all actors are like that of course, others are workers, services, ...
>>>
>>> /Patrik
>>>
>>> [1] http://typesafe.com/activator/template/akka-cluster-sharding-scala
>>>
>>>
>>>>
>>>>
>>>> On Fri, Feb 21, 2014 at 12:28 PM, Richard Rodseth
>>>> <[email protected]>wrote:
>>>>
>>>>> I'm excited to see the new cluster-sharding activator template, which
>>>>> I think might address some of the confusion I've had about eventsourced
>>>>> DDD
>>>>> with an actor per aggregate root.
>>>>>
>>>>> Do I understand correctly that the actual instantiation of the Post
>>>>> processor actor is something that happens within the ClusterSharding
>>>>> pattern (which I confess I haven't studied yet). Perhaps that could be
>>>>> called out in the text.
>>>>>
>>>>> Is it fair to say the the actor-per-aggregate root approach *presumes*
>>>>> a memory image model which then implies sharding and hence the use of Akka
>>>>> cluster?
>>>>>
>>>>> Is there or will there be a non-clustered version of the same app?
>>>>> That might be instructive for those of us trying to wrap our heads around
>>>>> DDD, Event Sourcing, CQRS and Akka all at once :)
>>>>>
>>>>> I look forward to digging in further, but obviously have a lot to
>>>>> learn. Thanks for the template!
>>>>>
>>>>
>>>> --
>>>> >>>>>>>>>> Read the docs: http://akka.io/docs/
>>>> >>>>>>>>>> Check the FAQ: http://akka.io/faq/
>>>> >>>>>>>>>> Search the archives:
>>>> https://groups.google.com/group/akka-user
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>>>
>>>
>>>
>>> --
>>>
>>> Patrik Nordwall
>>> Typesafe <http://typesafe.com/> - Reactive apps on the JVM
>>> Twitter: @patriknw
>>>
>>> --
>>> >>>>>>>>>> Read the docs: http://akka.io/docs/
>>> >>>>>>>>>> Check the FAQ: http://akka.io/faq/
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>>
>>
> --
> >>>>>>>>>> Read the docs: http://akka.io/docs/
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--
Patrik Nordwall
Typesafe <http://typesafe.com/> - Reactive apps on the JVM
Twitter: @patriknw
--
>>>>>>>>>> Read the docs: http://akka.io/docs/
>>>>>>>>>> Check the FAQ: http://akka.io/faq/
>>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user
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