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From "Valentin Valchev (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (FELIX-4720) Web Console and Gogo rely on Log history buffer in the Log Service
Date Tue, 09 Dec 2014 09:00:28 GMT

    [ https://issues.apache.org/jira/browse/FELIX-4720?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14239158#comment-14239158

Valentin Valchev commented on FELIX-4720:

LogReaderService provides two ways of using it. Either by adding a log listener (which according
to your paper of OSGi Whiteboard pattern is wrong) or by using LogReaderService.getLog().

I don't see the second option deprecated so why we shouldn't use it?

And ..
a) who says, that the log service must be implemented by the framework. Its equinox choice.
In all other projects it is implemented as a bundle.
b) we are aware that we can loose events. But I trust the system integrator to configure the
log service how many events should go in the log queue. I cannot imagine that any system integrator
will be happy to configure every bundle that creates it's own log queue. If you go to a grocery
shop you will be very irritated to pay each item to a different cashier don't you? So would
be the integrator if he needs to configure 2 or 3 additional log queues. Probably all implementations
can set the size of the log queue to be 0 and webconsole/gogo will show no logs. But if that
is what the administrator of the system wants who am I to argue? 
c) again - it's equnox problem. The OSGi specifications doesn't say 'don't use it'
d) OSGi services are also vendor-independence. You can choose which particular implementation
to use. If equinox is trouble - there are many other implementations - pax logging, logback,
felix log service, knopflerfish log service, prosyst log service...

Web Console is also perfectly valid OSGi application, that relies on the standard. 

> Web Console and Gogo rely on Log history buffer in the Log Service
> ------------------------------------------------------------------
>                 Key: FELIX-4720
>                 URL: https://issues.apache.org/jira/browse/FELIX-4720
>             Project: Felix
>          Issue Type: Bug
>          Components: Gogo Command, Web Console
>            Reporter: Peter Kriens
> The OSGi Log Reader Service has a command to get the history of the log. However, the
specification states that this history can be empty. The Equinox framework is nowadays registering
a Log Reader Service that has such an empty history to prevent pinning objects in memory.

> Using the history this way was always at odds with the specification since the history
was only intended to hold the start up events. The primary model of the Log Service is a dispatcher.
> I suggest that the Gogo log command and the Web Console maintain their own history buffer
to become independent on this fragile history buffer in the Log Reader service.

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