Why doesn't RegexReplacementConverter support patterns for substitution?

[lw33]

I think supporting patterns would make it more flexible and useful.

[vy]

Could you provide us some example use cases? Do you have a particular need/problem that you are trying to address?

[lw33]

In some cases, my single log entry spans multiple lines, and using log collection tools like Filebeat might truncate such logs. Therefore, I want to rewrite these multi-line logs into single-line logs by replacing the line breaks. If the replace functionality supports the following configuration, I can conveniently achieve this functionality.

<PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss} %p [%t] %replace{%m}{\n}{%n%d{yyyy/MM/dd HH:mm:ss} %p [%t]}%n" />

A single log entry contains multiple lines.

2024-08-16 15:52:51 INFO [main] testtesttesttesttesttesttesttesttesttest
testtesttesttesttesttesttesttesttesttest
testtesttesttesttesttesttesttesttesttest
testtesttesttesttesttesttesttesttesttest
testtesttesttesttesttesttesttesttesttest
testtesttesttesttesttesttesttesttesttest
testtesttesttesttesttesttesttesttesttest
testtesttesttesttesttesttesttesttesttest

I want them to be output as multiple lines.

2024-08-16 15:53:25 INFO [main] testtesttesttesttesttesttesttesttesttest
2024/08/16 15:53:25 INFO [main]testtesttesttesttesttesttesttesttesttest
2024/08/16 15:53:25 INFO [main]testtesttesttesttesttesttesttesttesttest
2024/08/16 15:53:25 INFO [main]testtesttesttesttesttesttesttesttesttest
2024/08/16 15:53:25 INFO [main]testtesttesttesttesttesttesttesttesttest
2024/08/16 15:53:25 INFO [main]testtesttesttesttesttesttesttesttesttest
2024/08/16 15:53:25 INFO [main]testtesttesttesttesttesttesttesttesttest
2024/08/16 15:53:25 INFO [main]testtesttesttesttesttesttesttesttesttest

[vy]

I strongly discourage you from using Pattern Layout for structured logging[1] purposes. What if thread name contains a newline character? Or level? PL will easily fall short on adressing such corner cases, neither it was intended to do so. You are using the wrong tool. You should rather employ JSON Template Layout for structured logging. It is not only super customizable and efficient, it is designed with machine-to-machine communication (e.g., Filebeat feed) in mind. [1] https://logging.staged.apache.org/log4j/2.x/manual/layouts.html#structured-logging

[lw33]

Thank you for your advice.