[Hawkular-dev] Event Store

[Juraci Paixão Kröhling]

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On 05/08/2015 10:57 AM, Gary Brown wrote:
> Hi
> 
> As discussed yesterday, we need a general event store that can
> persist relevant events off the bus. However we didn't decide where
> this functionality should reside, whether in an existing component
> or in a new component.
> 
> Although it could be provided as a separate component, I am not
> sure we have any use cases where it would be used independent of
> the bus, so think it is probably best to include it as additional
> functionality within the Bus component.
> 
> Agree/disagree?

With the micro-services approach in mind, I'd vote for a separate
component for the event-store. Such component has a potential to grow
in scope on the long term.

> The other issues are:
> 
> - how to determine which events should be persisted, as we may want
> some events to trigger further processing by subscribers on the
> bus, but not necessarily be stored for historic analysis. - for the
> event store we will need to know the type of the event being
> stored
> 
> So one possible solution to both these issues is, if the 'type' of
> the event is provided (possibly as a header value), then it will be
> persisted?

Could you give some examples of what "type" would be? I remember
hearing "deployment" as one of the possible types, but would be
interesting to think of some other cases.

I think there could also be a "group" or "category". This way, it
would be possible to easily switch the persist/discard flag for a
given set of types, depending on the current needs. For instance,
"store all events for category 'application'" might be useful during
an outage.

> Then within Elasticsearch, we can use the tenant/persona as the
> Index (to truly segment the data) and the event type to ensure
> different information types are partitioned/indexed appropriately.

+1

- - Juca.
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