Competing consumers on the JVM?

EventStoreDB
#1

Hello,

is there a way to use competing consumers from a JVM client?

I was looking at https://github.com/EventStore/EventStore.JVM but I think competing consumers are not supported there yet.

Otherwise, there’s the HTTP API, but I can’t find docs on how to create a persistent subscription? (I’m looking at http://docs.geteventstore.com/http-api/3.0.3/reading-streams/) Anyway I suppose the HTTP API would have some performance hit because of all the XML.

Or is there some other way?

Thanks,

Adam

#2

The competing consumer http api isn't released yet but you can take a
look at it here.
https://github.com/EventStore/EventStore/tree/chrisgreghttp its
basically there but has not been tested/merged into dev. You are right
in that it will also be slower than the TCP version if for no other
reason than its a pull model where as TCP is a push model

The stuff for creating etc IS there already over http see:

protected override void SubscribeCore(IHttpService service)
{
Register(service, "/subscriptions/{stream}/{subscription}",
HttpMethod.Get, GetSubscriptionInfo, Codec.NoCodecs, DefaultCodecs);
Register(service, "/subscriptions/{stream}", HttpMethod.Get,
GetSubscriptionInfoForStream, Codec.NoCodecs, DefaultCodecs);
Register(service, "/subscriptions", HttpMethod.Get,
GetAllSubscriptionInfo, Codec.NoCodecs, DefaultCodecs);
Register(service, "/subscriptions/{stream}/{subscription}",
HttpMethod.Put, PutSubscription, DefaultCodecs, DefaultCodecs);
Register(service, "/subscriptions/{stream}/{subscription}",
HttpMethod.Post, PostSubscription, DefaultCodecs, DefaultCodecs);
RegisterUrlBased(service, "/subscriptions/{stream}/{subscription}",
HttpMethod.Delete, DeleteSubscription);
RegisterUrlBased(service,
"/subscriptions/{stream}/{subscription}/replayParked",
HttpMethod.Post, ReplayParkedMessages);
}

the jvm api does not yet have support but this is underway it is not a
huge amount of work...

#3

Thanks! So I guess for a performance test the best bet would be using the .NET client :slight_smile:

As for HTTP being pull, I thought that maybe you are streaming the feed incrementally to the client as new events arrive (like in comet), but I didn’t read how this works exactly in ES.

Adam

#4

We could do something like that. As of now we have kept an atom style
format (its in that branch)