Log4j2 left pad filename with zeroes

Question

Is there a way to left pad with zeroes in the rolling file appender of log4j?

For instance myfile-00001.txt

I'm using a 3rd party log processor that reads files in lexicographical order so the the files must be left padded...

I added the following in the filePattern of log4j but I get spaces.

${logPath}/myfile-%05i.txt

score 3 · Accepted Answer · edited May 23 '17 at 12:09

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Log4j2 does not currently provide this out of the box. You can add a feature request on the log4j2 Jira issue tracker.

Meanwhile, as a workaround you can implement a custom lookup (https://stackoverflow.com/a/27418802/1446916) that generates a zero padded counter and use this in the filePattern of your RollingFile appender configuration.

edited May 23 '17 at 12:09

Community

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answered Jan 30 '16 at 02:51

Remko Popma

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This would be relatively easy to do. The syntax would most likely be %i{format} where the format could be anything you could pass to String.format for an integer value. – rgoers Jan 31 '16 at 17:01

score 2 · Answer 2 · answered Oct 24 '18 at 07:37

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I created a JIRA Ticket for this issue and also prepared a pull request that solves it. I would be glad if this was included in the next release of Log4j2.

answered Oct 24 '18 at 07:37

radlan

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Looks like the pull request was [accepted](https://github.com/apache/logging-log4j2/pull/224). – Archie Aug 17 '23 at 21:25

Log4j2 left pad filename with zeroes

2 Answers2