java 如何删除旧的滚动 log4j2 日志，最多保留 10 个文件？
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How to delete older rolled over log4j2 logs, keeping up to 10 files?
提问by pdeva
What I want is:
我想要的是：
- Maximum of 10 log files, in total
- Each log file, not more than 50MB in size.
- 总共最多 10 个日志文件
- 每个日志文件，大小不超过 50MB。
Thus the logs folder never grows over (50MB *10 )= 500MB.
因此，日志文件夹永远不会超过 (50MB *10 )= 500MB。
But it seems my log4j2 config is not properly done.
但似乎我的 log4j2 配置没有正确完成。
What is happening is:
正在发生的事情是：
- Logs do roll over after 50 MB
- But there are upto 10 logs kept per day
- Thus there is no limit of number of log files kept in log folder (since for eg, in 2 days, 20 logs of 50mb each have collected)
- 日志在 50 MB 后会翻转
- 但是每天最多保存 10 个日志
- 因此，日志文件夹中保存的日志文件数量没有限制（因为例如，在 2 天内，收集了 20 个 50mb 的日志）
Here is the config:
这是配置：
<Configuration status="WARN">
<Appenders>
<RollingFile name="RollingFile" fileName="log/my.log" filePattern="log/my-%d{MM-dd-yyyy}-%i.log">
<PatternLayout>
<Pattern>%d %p %c{1.} [%t] %m%n</Pattern>
</PatternLayout>
<Policies>
<OnStartupTriggeringPolicy />
<TimeBasedTriggeringPolicy />
<SizeBasedTriggeringPolicy size="50 MB"/>
</Policies>
<DefaultRolloverStrategy max="10"/>
</RollingFile>
</Appenders>
<Loggers>
<Root level="info">
<AppenderRef ref="RollingFile"/>
</Root>
</Loggers>
</Configuration>
What am I doing wrong?
我究竟做错了什么？
回答by Remko Popma
Since 2.5, Log4j supports a custom Delete actionthat is executed on every rollover.
从 2.5 开始，Log4j 支持在每次翻转时执行的自定义删除操作。
You can control which files are deleted by:
您可以通过以下方式控制删除哪些文件：
- Name (matching a globor a regex)
- Age("delete if 14 days old or older")
- Count ("keep only the most recent 3")
- Size ("keep only the most recent files up to 500MB")
The above can be combined. Instead of only specifying a size condition to keep disk usage down to max 500MB, it's a good idea to also match the name so you don't inadvertently delete unrelated files.
以上可以结合。与其仅指定大小条件以将磁盘使用量降低到最大 500MB，还不如匹配名称，以免无意中删除不相关的文件。
Users who need even more fine-grained control over which files to delete can specify a script condition using any supported JSR-223 scripting language.
需要更精细地控制要删除哪些文件的用户可以使用任何受支持的 JSR-223 脚本语言指定脚本条件。
Please check out the documentation, it has three full examples that may be useful.
请查看文档，它包含三个可能有用的完整示例。
For your question, this snippet may work:
对于您的问题，此代码段可能有效：
<DefaultRolloverStrategy>
<!--
* only files in the log folder, no sub folders
* only rolled over log files (name match)
* either when more than 10 matching files exist or when the max disk usage is exceeded
-->
<Delete basePath="log" maxDepth="1">
<IfFileName glob="my-??-??-????-*.log">
<IfAny>
<IfAccumulatedFileSize exceeds="500 MB" />
<IfAccumulatedFileCount exceeds="10" />
</IfAny>
</IfFileName>
</Delete>
</DefaultRolloverStrategy>
As an aside, note that you can compress log files on rolloverto make them take up less disk space.
顺便说一句，请注意，您可以在滚动时压缩日志文件，以减少它们占用的磁盘空间。
Finally, be careful! There is no way to recover files deleted this way. :-)
最后，小心！无法恢复以这种方式删除的文件。:-)
回答by Taha
The TimeBasedTriggeringPolicyworks based of the filePattern. Basically, the smallest unit of time in the file pattern (%d) is the triggering time interval. In your case the value is 'dd' hence the policy is triggered every day.
该TimeBasedTriggeringPolicy工程基础的filePattern。基本上，文件模式中的最小时间单位 ( %d) 是触发时间间隔。在您的情况下，该值为“dd”，因此该策略每天都会触发。
The presence of %i in your filePatternkeeps multiple log files for a day.
I would recommend trying without the %iin the filePattern.
%i 的存在会在filePattern一天内保留多个日志文件。我会建议您尝试不%i中filePattern。
