[LOG4J2-798] jar scanning for plugins too expensive and called too many times

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.1, 2.0.2
• Fix Version/s: 2.1
• Component/s: Core

Environment

modern hardware, fat jar

• Assignee: Unassigned
• Reporter: Ian Barfield
• Created: 25/Aug/14 15:55
• Updated: 25/Sep/14 21:41
• Resolved: 25/Sep/14 02:01

Description

related to: https://issues.apache.org/jira/browse/LOG4J2-741

It takes about 3 seconds to perform PluginManager.collectPlugins() and it appears to run 4 times before log4j2 is done initializing. That is pretty not okay. Please consider making the plugin discovery method configurable and/or curtailing the redundant calls.

My application jar uses the maven shade plugin. I do not specify a 'packages' attribute. I do use a custom plugin (a configuration factory), but I excluded the resultant plugin dat file created for it and specify its usage at runtime via the appropriate system property.

My suggestion for the easiest fix is to use the pre-computed plugin list and optionally (maybe even enabled by default) also scan the class path for custom plugins.

Some nice extras would be:

• removing the redundant collectPlugins() calls
• using a plugin dat file format that is both human friendly and amenable to append operations so that users of the maven shade plugin and users who struggle with annotation processors can easily include custom plugins. See https://github.com/addthis/codec for an example of such a plugin system/ file format that is based on hocon.