Hi, This online doc: Log4j – Configuring Log4j 2 (apache.org)<https://logging.apache.org/log4j/2.x/manual/configuration.html> describes “Automatic Configuration”:
“ Log4j has the ability to automatically configure itself during initialization. When Log4j starts it will locate all the ConfigurationFactory plugins and arrange them in weighted order from highest to lowest. As delivered, Log4j contains four ConfigurationFactory implementations: one for JSON, one for YAML, one for properties, and one for XML. 1. Log4j will inspect the "log4j2.configurationFile" system property and, if set, will attempt to load the configuration using the ConfigurationFactory that matches the file extension. Note that this is not restricted to a location on the local file system and may contain a URL. 2. If no system property is set the properties ConfigurationFactory will look for log4j2-test.properties in the classpath. 3. If no such file is found the YAML ConfigurationFactory will look for log4j2-test.yaml or log4j2-test.yml in the classpath. 4. If no such file is found the JSON ConfigurationFactory will look for log4j2-test.json or log4j2-test.jsn in the classpath. 5. If no such file is found the XML ConfigurationFactory will look for log4j2-test.xml in the classpath. 6. If a test file cannot be located the properties ConfigurationFactory will look for log4j2.properties on the classpath. 7. If a properties file cannot be located the YAML ConfigurationFactory will look for log4j2.yaml or log4j2.yml on the classpath. 8. If a YAML file cannot be located the JSON ConfigurationFactory will look for log4j2.json or log4j2.jsn on the classpath. 9. If a JSON file cannot be located the XML ConfigurationFactory will try to locate log4j2.xml on the classpath. 10. If no configuration file could be located the DefaultConfiguration will be used. This will cause logging output to go to the console. ” This looks like a flow diagram, if one does not match, then move down to next Decision Tree Node. So jumping to the end, a user can easily get a feeling that if someone made a mistake in one of the settings, then probably it would default to the 10, a default configuration – logging to Console would be happening. But is it true? If at the first Decision Tree Node, there is something set for System Property “log4j2.configurationFile”, but for whatever reasons, typo on the file path, incorrect format, or wrong extension, or wrong contents, Configuration could not succeed – I guess there could be two distinct set of situations, 1 is we could not get the configuration files; 2 is we could get to the file, but contents of the file throws up something we do not expect. – the 2nd set actually would not be different to any of the subsequent decision tree nodes, - we could find a configuration file, but we could not handle the contents, - so we will park this to a different topic. Getting back to decision tree node 1, if there is something set to “log4j2.configurationFile”, but following the value we could not locate a file, then what happens? Does it still move onto the next Decision Tree Node listed above? Or jump to the Decision Tree Node 10 directly? In “description” point of view, (some situations) could be said to be similar to the subsequent decision node – no such file specified in “log4j2.configurationFile” could be found, thus maybe it should move down the next decision tree node. >From a different angle, it could be said to be an Exceptional case within the >particular decision branch of the 1st Decision Tree Node, none of the other >Decision Tree Nodes apply anymore. So do we agree there is a bit ambiguity here? Would you be able to determine what would be the behavior without reading into the source code? Should we refine this document section a bit to describe more clearly what would be the behavior? Fumin Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows The information in this e-mail communication together with any attachments is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. If you are not the intended recipient of this e-mail communication, please notify us immediately. Any views expressed in this e-mail communication are those of the individual sender, unless otherwise specifically stated. Charles River Development does not represent, warrant or guarantee that the integrity of this communication has been maintained or that the communication is free of errors, virus or interference.
