Configuring RollingFileAppender in log4j

问题:

I'm working on a set of web services and we'd like to have a daily rotated log.

I'm trying to get org.apache.log4j.rolling.RollingFileAppender from the log4j extras companion working, since the documentation suggests this is best for production environments.

I have both the main log4J library (log4j-1.2.15.jar) and the log4j extras library (apache-log4j-extras-1.1.jar) on the classpath.

I have the following configuration for the appender in the log4j.properties file:

### SOAP Request Appender
log4j.appender.request=org.apache.log4j.rolling.RollingFileAppender
log4j.appender.request.File=SOAPmessages.log
log4j.appender.request.RollingPolicy=org.apache.log4j.rolling.TimeBasedRollingPolicy
log4j.appender.request.RollingPolicy.ActiveFileName =SOAPmessages-%d.log
log4j.appender.request.RollingPolicy.FileNamePattern=SOAPmessages-%d.log.zip
log4j.appender.request.layout = org.apache.log4j.PatternLayout
log4j.appender.request.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n

However, when I start the web service with log4j in debug mode I get these error messages:

log4j: Parsing appender named "request".
log4j: Parsing layout options for "request".
log4j: Setting property [conversionPattern] to [%d{ABSOLUTE} %5p %c{1}:%L - %m%n].
log4j: End of parsing for "request".
log4j: Setting property [file] to [/logs/SOAPmessages.log].
log4j:WARN Failed to set property [rollingPolicy] to value "org.apache.log4j.rolling.TimeBasedRollingPolicy". 
log4j:WARN Please set a rolling policy for the RollingFileAppender named 'request'
log4j: Parsed "request" options.

I've found documentation about how to configure this appender a little sparse, so can anyone help me fix my configuration?

EDIT0: Added debug mode output, rather than just the standard warnings

回答1:

Update: at least as early as 2013 (see Mubashar's comment) this started working.

---

According to Log4jXmlFormat you cannot configure it with log4j.properties, but only using the XML config format:

Note that TimeBasedRollingPolicy can only be configured with xml, not log4j.properties

Unfortunately, the example log4j.xml they provide doesn't work either:

log4j:ERROR Parsing error on line 14 and column 76
log4j:ERROR Element type "rollingPolicy" must be declared.
...
log4j:WARN Please set a rolling policy for the RollingFileAppender named 'FILE'

回答2:

I had a similar problem and just found a way to solve it (by single-stepping through log4j-extras source, no less...)

The good news is that, unlike what's written everywhere, it turns out that you actually CAN configure TimeBasedRollingPolicy using log4j.properties (XML config not needed! At least in versions of log4j >1.2.16 see this bug report)

Here is an example:

log4j.appender.File = org.apache.log4j.rolling.RollingFileAppender
log4j.appender.File.rollingPolicy = org.apache.log4j.rolling.TimeBasedRollingPolicy
log4j.appender.File.rollingPolicy.FileNamePattern = logs/worker-${instanceId}.%d{yyyyMMdd-HHmm}.log

BTW the ${instanceId} bit is something I am using on Amazon's EC2 to distinguish the logs from all my workers -- I just need to set that property before calling PropertyConfigurator.configure(), as follow:

p.setProperty("instanceId", EC2Util.getMyInstanceId());
PropertyConfigurator.configure(p);

回答3:

Faced more issues while making this work. Here are the details:

1. To download and add apache-log4j-extras-1.1.jar in the classpath, didn't notice this at first.
2. The RollingFileAppender should be org.apache.log4j.rolling.RollingFileAppender instead of org.apache.log4j.RollingFileAppender. This can give the error: log4j:ERROR No output stream or file set for the appender named [file].
3. We had to upgrade the log4j library from log4j-1.2.14.jar to log4j-1.2.16.jar.

Below is the appender configuration which worked for me:

<appender name="file" class="org.apache.log4j.rolling.RollingFileAppender">
        <param name="threshold" value="debug" />
        <rollingPolicy name="file"
            class="org.apache.log4j.rolling.TimeBasedRollingPolicy">
            <param name="FileNamePattern" value="logs/MyLog-%d{yyyy-MM-dd-HH-mm}.log.gz" />
            <!-- The below param will keep the live update file in a different location-->
            <!-- param name="ActiveFileName" value="current/MyLog.log" /-->
        </rollingPolicy>

        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%5p %d{ISO8601} [%t][%x] %c - %m%n" />
        </layout>
</appender>

回答4:

Toolbear74 is right log4j.XML is required. In order to get the XML to validate the <param> tags need to be BEFORE the <rollingPolicy> I suggest setting a logging threshold <param name="threshold" value="info"/>

When Creating a Log4j.xml file don't forget to to copy the log4j.dtd into the same location.

Here is an example:

<?xml version="1.0" encoding="windows-1252"?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd" >
<log4j:configuration>
<!-- Daily Rolling File Appender that compresses old files -->
  <appender name="file" class="org.apache.log4j.rolling.RollingFileAppender" >
     <param name="threshold" value="info"/>
     <rollingPolicy name="file"  
                      class="org.apache.log4j.rolling.TimeBasedRollingPolicy">
        <param name="FileNamePattern" 
               value="${catalina.base}/logs/myapp.log.%d{yyyy-MM-dd}.gz"/>
        <param name="ActiveFileName" value="${catalina.base}/logs/myapp.log"/>
     </rollingPolicy>
     <layout class="org.apache.log4j.EnhancedPatternLayout" >
        <param name="ConversionPattern" 
               value="%d{ISO8601} %-5p - %-26.26c{1} - %m%n" />
    </layout>
  </appender>

  <root>
    <priority value="debug"></priority>
    <appender-ref ref="file" />
  </root>
</log4j:configuration>

Considering that your setting a FileNamePattern and an ActiveFileName I think that setting a File property is redundant and possibly even erroneous

Try renaming your log4j.properties and dropping in a log4j.xml similar to my example and see what happens.

回答5:

Regarding error: log4j:ERROR Element type "rollingPolicy" must be declared

1. Use a log4j.jar version newer than log4j-1.2.14.jar, which has a log4j.dtd defining rollingPolicy.
2. of course you also need apache-log4j-extras-1.1.jar
3. Check if any other third party jars you are using perhaps have an older version of log4j.jar packed inside. If so, make sure your log4j.jar comes first in the order before the third party containing the older log4j.jar.

回答6:

In Log4j2, the "extras" lib is not mandatory any more. Also the configuration format has changed.

An example is provided in the Apache documentation

property.filename = /foo/bar/test.log

appender.rolling.type = RollingFile
appender.rolling.name = RollingFile
appender.rolling.fileName = ${filename}
appender.rolling.filePattern = /foo/bar/rolling/test1-%d{MM-dd-yy-HH-mm-ss}-%i.log.gz
appender.rolling.layout.type = PatternLayout
appender.rolling.layout.pattern = %d %p %C{1.} [%t] %m%n
appender.rolling.policies.type = Policies
appender.rolling.policies.time.type = TimeBasedTriggeringPolicy
appender.rolling.policies.time.interval = 2
appender.rolling.policies.time.modulate = true
appender.rolling.policies.size.type = SizeBasedTriggeringPolicy
appender.rolling.policies.size.size=100MB
appender.rolling.strategy.type = DefaultRolloverStrategy
appender.rolling.strategy.max = 5


logger.rolling.name = com.example.my.class
logger.rolling.level = debug
logger.rolling.additivity = false
logger.rolling.appenderRef.rolling.ref = RollingFile

回答7:

I'm suspicious of the ActiveFileName property. According to the log4j javadoc, there isn't such a property on the TimeBasedRollingPolicy class. (No setActiveFileName or getActiveFileName methods.)

I don't know what specifying an unknown property would do, but it is possible that it will cause the containing object to be abandoned, and that could lead to the warnings that you saw.

Try leaving it out and seeing what happens.

回答8:

You have a bad package name

org.apache.log4j.rolling.RollingFileAppender 

The correct one is:

org.apache.log4j.RollingFileAppender