My logs are extracted, piped and consolidated into elasticsearch. Multiline events are hard to track and diagnose.
Instead of playing with collectors and regular expressions to group exception lines in a single record, is there a way with logback configuration to have Exception stacktrace on a single line ?
You can declare a conversion rule in your logback.xml for the %ex symbolic like so:
<?xml version="1.0" encoding="UTF-8" ?>
<configuration>
<conversionRule conversionWord="ex" converterClass="com.foo.CompressedStackTraceConverter" />
...
</configuration>
Then declare CompressedStackTraceConverter like so:
import ch.qos.logback.classic.pattern.ThrowableProxyConverter;
import ch.qos.logback.classic.spi.IThrowableProxy;
public class CompressedStackTraceConverter extends ThrowableProxyConverter {
@Override
protected String throwableProxyToString(IThrowableProxy tp) {
String original = super.throwableProxyToString(tp);
// replace the new line characters with something,
// use your own replacement value here
return original.replaceAll("\n", " ~~ ");
}
}
This custom conversion specifier will work as long as your logging pattern contains the %ex symbolic. For example, a pattern like this:
<encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
<pattern>%d{yyyy-MM-dd HH:mm:ss}|%-5level|%logger{36}|%msg %ex %n</pattern>
</encoder>
If your pattern does not include the %ex symbolic then the stacktrace is part of the %msg in which case you would declare the conversion rule like this ...
<conversionRule conversionWord="msg" converterClass="com.foo.CompressedStackTraceConverter" />
... though this would have the effect of applying the CompressedStackTraceConverter to your entire log message, not just to the stack trace portion of it.