Clustering - WebHooks

[Mark Burridge]

Hi,

I'm evaluating VerneMQ  and so far, in the single node test environment it seems to provide everything I need for my implementation. Essentially, i need to capture/persist to the database based on message content.

In Production i will be clustering the Nodes on individual servers, behind a network load balancer. What I'm unable to determine from the documentation is if the webhooks are localized.

E.G:
Node A and Node B have Client A and Client B respectively subscribed to the same topic.

If client A publishes to the topic, will the "on_publish" web hook be called from Node A or both Node A and B.  

It would seem logical to call the hook only from Node A, but without setting up multiple nodes I'm unable to verify.

I'd greatly appreciate any insight.

Thanks

[André Fatton]

Hi Mark,

all plugin hooks are localized, yes.

So, on_publish will be called on Node A in your scenario. Note that this is unrelated to the fact that the publisher is also a subscriber here.

Note that on_deliver will be called twice. You could consider on_publish relating to incoming messages, and on_deliver relating to outgoing messages.

Hope this helps. A 2-node cluster is quick to setup, so you should be able to easily test all this.

Cheers,

André

[Mark Burridge]

Hi André

Thanks for the prompt reply. The on_publish was the only real concern as I'll need to update a centralized store. The on_delivered is less important as I'll have other ways of verifying delivery. I'm testing on a single node whilst I formulate proof of concept. I will certainly setup a test environment with multiple nodes behind a load balancer before moving to the development phase.

Thanks for the added insight.