[SOLR-15610] Support json formatted logging via conf: add log4j-layout-template-json to 'server'

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 9.0, 8.10
• Assignee: Chris M. Hostetter
• Reporter: Chris M. Hostetter
• Created: 31/Aug/21 21:24
• Updated: 30/May/22 10:12
• Resolved: 02/Sep/21 18:51

Description

JSON Formatted logging is becoming wide spread enough that it seems like we should support it as an option in Solr.

Assuming we upgrade to log4j >= 2.14.0  (SOLR-15609) then this becomes possible for people to do by:

1. downloading the log4j-layout-template-json.jar that corresponds with the lof4j version used by their solr version
2. include the log4j-layout-template-json.jar in the (jetty) classpath via SOLR_OPTS (can't be loaded as a solr plugin because it needs to be used on startup)
3. specify their own LOG4J_PROPS file that configures log4j to use a JsonTemplateLayout

..but steps #1 and #2 are a bit hairy.  Particularly step #1 as it means every time users upgrade solr they have to pay careful attention to if/when the log4j deps change.

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I would like to propose that we make this easier, by adding log4j-layout-template-json as a dependency for the "server" module, so that it is available out of the box when running solr – that way JSON logging can be enabled easily with a simple LOG4J_PROPS change.

Issue Links

• is blocked by: SOLR-15609 Upgrade log4j -> 2.14.1
• is related to: SOLR-14699 Solr request logs should escape names, values (SolrQueryResponse.getToLogAsString)