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Date: Tue, 9 Dec 2014 16:13:12 +0000 (UTC)
From: "Marcel Offermans (JIRA)" <jira@apache.org>
To: dev@felix.apache.org
Message-ID: <JIRA.12759629.1417769342000.110316.1418141592320@Atlassian.JIRA>
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Subject: [jira] [Commented] (FELIX-4720) Web Console and Gogo rely on Log
 history buffer in the Log Service
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    [ https://issues.apache.org/jira/browse/FELIX-4720?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14239584#comment-14239584 ] 

Marcel Offermans commented on FELIX-4720:
-----------------------------------------

The discussion is about whether or not we should solve this in web console, the gogo command and any other consumer of the LogReaderService at all. Or elsewhere.

The argument you make about building in all kinds of different options inside the implementation and enable them using configuration is only one possible solution. Although it's always hard to make generic statements, I would prefer a solution where we implement this in a different bundle altogether, and simply not deploy that bundle if we don't need it. I would also prefer in this case not to implement it for every consumer, but instead change the provider.

Make a small bundle that is a LogListener and that caches the number of entries you want. Make that bundle implement a LogReaderService with a higher ranking and all consumers can bind to that. No need to change webconsole, or the log command, or any other consumer.

> 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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