[LOG4J2-2602] Same file is overwritten on rollover which causes logs loss

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.11.2
• Fix Version/s: 2.12.0
• Component/s: Appenders
• Assignee: Unassigned
• Reporter: Vitaliy MAtuzko
• Created: 07/May/19 20:14
• Updated: 06/Aug/19 04:23
• Resolved: 12/May/19 22:38

Description

In our log4j configuration we use SizeBasedTriggeringPolicy and DefaultRolloverStrategy(max>1) :

    <Appenders>
        <RollingRandomAccessFile name="file" fileName="log/server.log"
                                 filePattern="log/server-%d{yyyy-MM-dd'T'HH-mm-ss}.log.gz">
            <PatternLayout>
                <pattern>%level{length=1} %date{MMdd-HHmm:ss,SSS} %logger{1.} %message %X
                    [%thread]%n
                </pattern>
            </PatternLayout>
            <Policies>
                <OnStartupTriggeringPolicy/>
                <SizeBasedTriggeringPolicy size="10 MB"/>
            </Policies>
            <DefaultRolloverStrategy max="2000"/>
        </RollingRandomAccessFile>
    </Appenders>

 

After upgrading to log4j-core 2.11.2 we have noticed that after rollover insttead of creating new files same file gets overwritten.

Looks like the issue is that

org.apache.logging.log4j.core.appender.rolling.PatternProcessor#formatFileName gives same filename for rollover, and the difference between 2.11.1 version is that field "prevFileTime" never reseted after first time*:*

2.11.2 org.apache.logging.log4j.core.appender.rolling.PatternProcessor#updateTime

public void updateTime() {
 if (nextFileTime != 0) {
 prevFileTime = nextFileTime;
}
 }

 

it was always reseted in 2.11.1

2.11.1 org.apache.logging.log4j.core.appender.rolling.PatternProcessor#updateTime

public void updateTime() {
 prevFileTime = nextFileTime;
}

 

so the same time(prevFileTime) will be always used to form the filename for rollover

org.apache.logging.log4j.core.appender.rolling.PatternProcessor#formatFileName(org.apache.logging.log4j.core.lookup.StrSubstitutor, java.lang.StringBuilder, boolean, java.lang.Object)

final long time = useCurrentTime ? currentFileTime != 0 ? currentFileTime : System.currentTimeMillis() :
 prevFileTime != 0 ? prevFileTime : System.currentTimeMillis();