Log4j 2.x makes it possible to natively output logs in JSON format, without the need for additional plugins.
Example configuration
Here is a basic configuration example for outputting logs in JSON format. The presented configuration stores logs in a daily rolling file named alfresco.json, with each log statement being represented as an individually valid JSON fragment presented in a single line and separated from the next by a new line.
For more fine-grained control over the desired output, see the official Log4j 2.x documentation, JSON Layout. This offers an exhaustive explanation about all the properties specific to the JSON Layout that can be configured.
rootLogger.level=error
rootLogger.appenderRef.json.ref=JsonAppender
###### Daily JSON rolling file appender definition #######
appender.json.type=RollingFile
appender.json.name=JsonAppender
appender.json.fileName=alfresco.json
appender.json.filePattern=alfresco.json.%d{yyyy-MM-dd}
appender.json.layout.type=JsonLayout
appender.json.layout.eventEol=true
appender.json.layout.compact=true
appender.json.policies.type=Policies
appender.json.policies.time.type=TimeBasedTriggeringPolicy
appender.json.policies.time.interval=1
Example output
Given the configuration above, the alfresco.json file would look similar to the following:
{"instant":{"epochSecond":1669033790,"nanoOfSecond":415261100},"thread":"localhost-startStop-1","level":"INFO","loggerName":"org.springframework.extensions.webscripts.DeclarativeRegistry","message":"Registered 0 Schema Description Documents (+0 failed) ","endOfBatch":false,"loggerFqcn":"org.apache.commons.logging.impl.SLF4JLocationAwareLog","threadId":129,"threadPriority":5}
{"instant":{"epochSecond":1669033790,"nanoOfSecond":420403300},"thread":"localhost-startStop-1","level":"INFO","loggerName":"org.springframework.extensions.webscripts.AbstractRuntimeContainer","message":"Initialised Public Api Web Script Container (in 2563.5293ms)","endOfBatch":false,"loggerFqcn":"org.apache.commons.logging.impl.SLF4JLocationAwareLog","threadId":129,"threadPriority":5}
{"instant":{"epochSecond":1669033790,"nanoOfSecond":475128400},"thread":"asynchronouslyRefreshedCacheThreadPool1","level":"INFO","loggerName":"org.springframework.extensions.webscripts.DeclarativeRegistry","message":"Registered 14 Web Scripts (+0 failed), 103 URLs","endOfBatch":false,"loggerFqcn":"org.apache.commons.logging.impl.SLF4JLocationAwareLog","threadId":133,"threadPriority":5}
{"instant":{"epochSecond":1669033790,"nanoOfSecond":475128400},"thread":"asynchronouslyRefreshedCacheThreadPool1","level":"INFO","loggerName":"org.springframework.extensions.webscripts.DeclarativeRegistry","message":"Registered 0 Package Description Documents (+0 failed) ","endOfBatch":false,"loggerFqcn":"org.apache.commons.logging.impl.SLF4JLocationAwareLog","threadId":133,"threadPriority":5}
{"instant":{"epochSecond":1669033790,"nanoOfSecond":476132900},"thread":"asynchronouslyRefreshedCacheThreadPool1","level":"INFO","loggerName":"org.springframework.extensions.webscripts.DeclarativeRegistry","message":"Registered 0 Schema Description Documents (+0 failed) ","endOfBatch":false,"loggerFqcn":"org.apache.commons.logging.impl.SLF4JLocationAwareLog","threadId":133,"threadPriority":5}
{"instant":{"epochSecond":1669033819,"nanoOfSecond":711004700},"thread":"http-bio-8080-exec-1","level":"INFO","loggerName":"org.alfresco.repo.management.subsystems.ChildApplicationContextFactory","message":"Starting 'Search' subsystem, ID: [Search, managed, solr6]","endOfBatch":false,"loggerFqcn":"org.apache.commons.logging.impl.SLF4JLocationAwareLog","threadId":318,"threadPriority":5}
{"instant":{"epochSecond":1669033820,"nanoOfSecond":425889600},"thread":"http-bio-8080-exec-1","level":"INFO","loggerName":"org.alfresco.repo.management.subsystems.ChildApplicationContextFactory","message":"Startup of 'Search' subsystem, ID: [Search, managed, solr6] complete","endOfBatch":false,"loggerFqcn":"org.apache.commons.logging.impl.SLF4JLocationAwareLog","threadId":318,"threadPriority":5}
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