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From "Daniel (JIRA)" <j...@apache.org>
Subject [jira] [Comment Edited] (CAMEL-7905) New option to ignore missing consumers on direct endpoints
Date Fri, 28 Nov 2014 08:49:12 GMT

    [ https://issues.apache.org/jira/browse/CAMEL-7905?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14228156#comment-14228156
] 

Daniel edited comment on CAMEL-7905 at 11/28/14 8:48 AM:
---------------------------------------------------------

[~boday] - Even if it sounds wrong in the first place, I actually would discard the messages.

In the scenario described above, it is a valid situation that there is no consumer for a direct
endpoint. And what else would you want to do, if no one is interested in the messages an endpoint
produces, but to discard the messages. You can't wait as you don't know, if there will ever
be a consumer for the message and you probably would not want an Exception to be thrown as
Exceptions are a very costly way for flow-control, if they occur on a regular basis in a "normal"
application state. That is discarding the message is the best option you have. As this is
may lead to message loss where endpoints without consumers are not a valid application state,
this definitively should be an opt-in option!


was (Author: dpr):
[~boday] - Even if it sounds wrong in the first place, I actually would discard the messages.

In the scenario described above, it is a valid situation that there is no consumer for a direct
endpoint. And what else would you want to do, if no one is interested in the messages an endpoint
produces, but to discard the messages. You can't wait as you don't know, if there will ever
be a consumer for the message and you probably would not want an Exception to be thrown as
Exceptions are a very costly way for flow-control, if they occur on a regular basis in a "normal"
application state. That is discarding the message is the best option you have. As this is
may lead to messages loss where endpoints without consumers are not a valid application state,
this definitively should be an opt-in option!

> New option to ignore missing consumers on direct endpoints
> ----------------------------------------------------------
>
>                 Key: CAMEL-7905
>                 URL: https://issues.apache.org/jira/browse/CAMEL-7905
>             Project: Camel
>          Issue Type: Improvement
>    Affects Versions: 2.14.0
>            Reporter: Daniel
>
> Currently a {{DirectConsumerNotAvailableException}} or {{DirectVmConsumerNotAvailableException}}
is thrown when a message is send via a direct endoint and no consumer has been set up for
this endpoint.
> In a current scenario I want to use camel to loosely couple two components using direct
endpoints that _might_ be consumed by some bean. Especially there should be no dependency
from the producing component to the consuming component. However, if there is a consumer,
messages send from the producer must be consumed synchronously in the same thread to preserve
the transaction context of the producer. That why I chose {{direct}} for the producer's endpoint.
> What is meant by "the messages might be consumed" is that the consuming component might
not be deployed, when the consumer produces the first messages, or perhaps will never be deployed.
I know there is the {{block}} option for the {{direct}} component but I don't want the producer
to wait for the consumer as it might take some time (possibly forever) for the consumer to
be available.
> I think this is a very common scenario for a messaging system and I was surprised not
to find an easy out-of-the-box way to handle this with camel. That's why I think an additional
option {{failIfNoConsumers}} (similar to the option for the seda component) for the {{direct}}
and {{direct-vm}} component would be very handy.



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