Matthew Hill created LOG4J2-2061:
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Summary: RollingFileManager not removed when RollingFileAppender
is stopped, using DirectWriteRolloverStrategy
Key: LOG4J2-2061
URL: https://issues.apache.org/jira/browse/LOG4J2-2061
Project: Log4j 2
Issue Type: Bug
Components: Core
Affects Versions: 2.9.0
Environment: *
Reporter: Matthew Hill
Priority: Blocker
When programmatically creating an instance of RollingFileAppender using
RollingFileAppender.newBuilder.(config options).build(), an instance of
RollingFileManager is created in AbstractManager.getManager(...), and this
instance is stored in the hashmap AbstractManager.MAP as well as on the
instance of RollingFileAppender in the super class
AbstractOutputStreamAppender. This manager is created and stored in the
AbstractManager.MAP with the name FILE_PATTERN (since we cannot create an
instance of RollingFileAppender with a file name using the
DirectWriteRolloverStrategy). However, the same manager is created with a NAME
of NULL since it is trying to use file name as the name of the manager, but
this parameter is not allowed using DirectWriteRolloverStrategy.
The problem here is that the RollingFileManager is created with a name of FILE
NAME (i.e., NULL when using DirectWriteRolloverStrategy) and added to the
hashmap with a key of FILE PATTERN, but when the rolling file appender is
stopped, it attempts to remove its manager from this MAP using
RollingFileManager.name, which equates to FILE NAME which is NULL.
Consider the following example:
* create a rolling file appender using the DirectWriteRolloverStrategy with a
file pattern of 'output.%i.log'
* a RollingFileManager is created with the name NULL, but put in
AbstractManager.MAP with the name 'output.%i.log'
* the rolling file appender is used to write a few line of log file
* the rolling file appender is stopped using RollingFileAppender.stop(..)
* the RollingFileManager is NOT removed from AbstractManager.MAP since it is
trying to remove FILE NAME but it is keyed on FILE PATTERN
* a NEW instance of rolling file appender is created using the
DirectWriteRolloverStrategy with the SAME file pattern of 'output.%i.log'.
* a new instance of RollingFileManager is NOT created, as it already exists in
the MAP, so the old instance is simply returned
* the instance of RollingFileManager for the new instance of
RollingFileAppender has a closed output stream, meaning that no logging is
possible.
In the above example you can see that if the old rolling file appender's output
stream is closed, and a new instance created with the same file pattern, then
the old manager will be used. I see no easy way of recreating this output
stream.
I found no documentation regarding why one cannot set the FILE NAME for a
RollingFileAppender using DirectWriteRolloverStrategy. Being able to configure
this may also solve the problem (unless it causes issues elsewhere), but
another possible fix to this issue is to create the RollingFileManager with the
name FILE PATTERN when using the DirectWriteRolloverStrategy. This way we add
to the MAP the instance of RollingFileManager with the key FILE PATTERN, and we
remove from the MAP RollingFileManager.name which equals FILE PATTERN
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