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https://issues.apache.org/jira/browse/OAK-6770?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16397148#comment-16397148
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Francesco Mari commented on OAK-6770:
-------------------------------------
While investigating this issue, I figured out that the following sources are
looked up for configuration values in this order.
# The component configuration.
# The framework configuration.
# System properties, only for cache sizes.
The first source containing the configuration value wins. This doesn't seem to
make much sense. I would have expected the system properties to have precedence
over the component configuration, in order to give users a way to override
cache sizes on the command line for experimental usage.
Moreover, I quite don't understand the reason why configuration values are
looked up in the framework configuration, which is a flat namespace for
everything deployed in the OSGi framework. In addition to that, looking into
the framework properties also triggers a lookup in the system properties.
According to the Javadoc for {{org.osgi.framework.BundleContext#getProperty}},
{quote}
If the key is not found in the Framework properties, the system properties are
then searched. The method returns null if the property is not found.
{quote}
This behaviour modifies the lookup of configuration values to the following.
# The component configuration.
# The framework configuration.
# System properties, for every configuration.
# System properties, only for cache sizes.
This strategy basically makes every configuration property feature-flaggable as
long as they are not specified in an OSGi configuration which, in my opinion,
is quite arbitrary and dangerous. As such, I propose to stop looking up the
framework configuration, and to lookup system properties for cache sizes before
we look into the component configuration (which seems to be a saner approach to
configuration).
[~mduerig], [~dulceanu], [~volteanu], what do you think?
> Convert oak-segment-tar to OSGi R6 annotations
> ----------------------------------------------
>
> Key: OAK-6770
> URL: https://issues.apache.org/jira/browse/OAK-6770
> Project: Jackrabbit Oak
> Issue Type: Technical task
> Components: segment-tar
> Reporter: Robert Munteanu
> Assignee: Francesco Mari
> Priority: Minor
> Labels: osgi
> Fix For: 1.10
>
>
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