Log4j2 RollingFile Appender-在每个日志文件的开头添加自定义信息

Question

在java 1.7中使用log4j2（beta9）。

我的完整日志4J2。xml：

<?xml version="1.0" encoding="UTF-8"?>
<Configuration>
  <Properties>
    <Property name="projectPrefix">Tts</Property>
    <Property name="rawPattern">%d %-5p [%t] %C{2} (%F:%L) - %m%n</Property>
    <Property name="coloredPattern">%d %highlight{%-5p}{FATAL=bright red, ERROR=red, WARN=yellow, INFO=cyan, DEBUG=green, TRACE=bright blue} %style{[%t] %C{2} (%F:%L) -}{bright,black} %m%n</Property>
    <Property name="fileName">Log/${projectPrefix}.log</Property>
    <Property name="filePattern">Log/${projectPrefix}-%i.log</Property>
  </Properties>
  <Appenders>
    <Console name="Stdout" target="SYSTEM_OUT">
      <PatternLayout pattern="${coloredPattern}"/>
    </Console>
    <RollingFile name="Logfile" fileName="${fileName}" filePattern="${filePattern}">
      <PatternLayout pattern="${rawPattern}"/>
      <Policies>
        <SizeBasedTriggeringPolicy size="16 MB"/>
      </Policies>
      <DefaultRolloverStrategy fileIndex="min" max="16"/>
    </RollingFile>
  </Appenders>
  <Loggers>
    <Root level="info">
      <AppenderRef ref="Stdout"/>
      <AppenderRef ref="Logfile"/>
    </Root>
  </Loggers>
</Configuration>

我想在每个日志文件的顶部添加一些自定义信息，如我的应用程序的版本字符串、应用程序正常运行时间和系统正常运行时间。甚至在刚刚关闭的日志文件的底部写一些»再见，再见/eof«也可以。

当RollingFileAppander创建了一个新文件时，是否有类似于钩子或回调的东西可以得到通知，以便我可以首先将我的东西放入这些新的日志文件（或任何其他建议）？

Answer 1

目前没有用于翻转的回调挂钩。我可以建议将其作为log4j2问题跟踪器中的功能请求提出吗？

Answer 2

可用的新解决方案

自从这个问题被提出以来已经过去了一段时间，现在，当我想做同样的事情时，我发现可以在不干扰工厂的情况下解决，但这并不容易找到。log4j2团队通过配置使这成为可能。我希望我的帖子会有用，并为其他人节省时间。

他们在PatternLayout元素中隐藏了此功能。不是我第一次看的地方，但它起作用了，为什么还要抱怨呢？

这是我的配置（请注意页眉和页脚及其使用的属性）：

<?xml version="1.0" encoding="UTF-8"?>
<Configuration>
    <Properties>
        <Property name="log-path">${sys:catalina.home}/logs/my-app</Property>
        <Property name="archive">${log-path}/archive</Property>
        <Property name="defaultPattern">[%d] [%-5p] [%t] %C{5} - %m%n</Property>
        <Property name="defaultRollOverMax">450</Property>
        <Property name="fileHeader">[%d] Start of log \n========================================================================\n
Will be archived in ${archive}\n\n</Property>
        <Property name="fileFooter">\n========================================================================\n[%d] End of log</Property>
    </Properties>
    <Appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <ThresholdFilter level="INFO" onMatch="ACCEPT" onMismatch="DENY"/>
            <PatternLayout pattern="%highlight{[%d] [%-5p] [%t] %C{3} (%F:%L) - %m%n}" charset="UTF-8"/>
        </Console>

        <RollingFile name="Root"
                     fileName="${log-path}/root.log"
                     filePattern="${archive}/root.log.%d{yyyy-MM-dd}_%i.gz"
                     immediateFlush="true">
            <ThresholdFilter level="INFO" onMatch="ACCEPT" onMismatch="DENY"/>
            <Policies>
                <OnStartupTriggeringPolicy/>
                <SizeBasedTriggeringPolicy size="10 MB"/>
                <TimeBasedTriggeringPolicy/>
            </Policies>

            <PatternLayout pattern="${defaultPattern}"
                           charset="UTF-8"
                           header="This is the ROOT logger and it should be silent \n - define loggers when you see something in here"
                           footer="Closing"/>
            <DefaultRolloverStrategy max="${defaultRollOverMax}" fileIndex="max"/>
        </RollingFile>

        <RollingFile name="System"
                     fileName="${log-path}/system.log"
                     filePattern="${archive}/system.log.%d{yyyy-MM-dd}_%i.gz"
                     immediateFlush="true">
            <ThresholdFilter level="INFO" onMatch="ACCEPT" onMismatch="DENY" />
            <Policies>
                <OnStartupTriggeringPolicy/>
                <SizeBasedTriggeringPolicy size="10 MB"/>
                <TimeBasedTriggeringPolicy/>
            </Policies>
            <PatternLayout pattern="${defaultPattern}"
                           charset="UTF-8"
                           header="${fileHeader}"
                           footer="${fileFooter}"/>
            <DefaultRolloverStrategy max="${defaultRollOverMax}" fileIndex="max"/>
        </RollingFile>

        <RollingFile name="Error"
                     fileName="${log-path}/error.log"
                     filePattern="${archive}/error.log.%d{yyyy-MM-dd}_%i.gz"
                     immediateFlush="true">
            <ThresholdFilter level="WARN" onMatch="ACCEPT" onMismatch="DENY"/>
            <Policies>
                <OnStartupTriggeringPolicy/>
                <SizeBasedTriggeringPolicy size="10 MB"/>
                <TimeBasedTriggeringPolicy/>
            </Policies>
            <PatternLayout pattern="${defaultPattern}"
                           charset="UTF-8"
                           header="${fileHeader}"
                           footer="${fileFooter}"/>
            <DefaultRolloverStrategy max="${defaultRollOverMax}" fileIndex="max"/>
        </RollingFile>
    </Appenders>

    <Loggers>
        <Logger name="org.myOrganization.myApplication" additivity="false" level="INFO">
            <appender-ref ref="System"/>
            <appender-ref ref="Console"/>
            <appender-ref ref="Error"/>
        </Logger>

        <Logger name="org.myOrganization.myApplication.peculiarPackage" additivity="false" level="TRACE">
            <appender-ref ref="System"/>
            <appender-ref ref="Console"/>
            <appender-ref ref="Error"/>
        </Logger>

        <Logger name="org.springframework" additivity="false" level="WARN">
            <appender-ref ref="System"/>
            <appender-ref ref="Console"/>
            <appender-ref ref="Error"/>
        </Logger>

        <Logger name="javax" additivity="false" level="WARN">
            <appender-ref ref="System"/>
            <appender-ref ref="Console"/>
            <appender-ref ref="Error"/>
        </Logger>

        <!-- Root logger should be empty -->
        <Root level="all">
            <AppenderRef ref="Root"/>
            <AppenderRef ref="Console"/>
            <!--Make sure all errors are logged to the error log-->
            <appender-ref ref="Error"/>
        </Root>
    </Loggers>
</Configuration>

如您所见，我包含了一个时间戳和一个属性，其中包括一个系统属性。Log4j2可以显示许多不同类型的属性，通过它，您可以按照自己的要求完成很多事情。

日志文件如下所示：

[2016-08-09 17:00:43,924] Start of log 
========================================================================

Will be archived in /home/emanciperingsivraren/program/apache-tomcat-8.0.32/logs/my-app/archive

[2016-08-09 17:00:44,000] [INFO ] [RMI TCP Connection(2)-127.0.0.1]    [snip]

========================================================================
[2016-08-09 17:02:17,871] End of log

您需要更多自定义信息吗？-尝试将该信息放在属性、系统属性或log4j2可以读取的其他内容中。

有关您可以拥有的属性类型的详细信息，请参阅log4j2中的属性替换。

关于配置的注释

• 我使用属性而不是重复常见设置
• 如果在根记录器中写了一些东西，那么它是未处理的，应该写一个记录器来定义我们想用它做什么
• 由于错误/异常可以“隐藏”在许多其他日志消息中，因此它们也打印在那里，并且可以很容易地找到
• 控制台上打印的消息有不同的颜色

Answer 3

好的，通过像这里描述的那样扩展DefaultRolloverStrategy，可以有效地解决这个问题。但是

• 它需要大约150行代码（包括包装RolloverDescription和appender.rolling.helper.Action）和

为了让log4j2调用我们的工厂方法，log4j2的根标记。xml必须与我们类的包一起归属，例如：

<Configuration packages="de.jme.toolbox.logging">
...
</Configuration>

在我们自己的滚动策略中，我们必须处理这里描述的插件和插件。

最后在这里我完整的log4j2.xml（你不需要所有的属性-这只是我喜欢如何配置我的日志）：

<?xml version="1.0" encoding="UTF-8"?>
<Configuration packages="de.jme.toolbox.logging">
  <Properties>
    <Property name="projectPrefix">Tts</Property>
    <Property name="rawPattern">%d %-5p [%t] %C{2} (%F:%L) - %m%n</Property>
    <Property name="coloredPattern">%d %highlight{%-5p}{FATAL=bright red, ERROR=red, WARN=yellow, INFO=cyan, DEBUG=green, TRACE=bright blue} %style{[%t] %C{2} (%F:%L) -}{bright,black} %m%n</Property>
    <Property name="coloredShortPattern">%d %highlight{%-5p}{FATAL=bright red, ERROR=red, WARN=yellow, INFO=cyan, DEBUG=green, TRACE=bright blue} %style{[%t] -}{bright,black} %m%n</Property>
    <Property name="fileName">Log/${projectPrefix}.log</Property>
    <Property name="filePattern">Log/${projectPrefix}-%i.log</Property>
  </Properties>
  <Appenders>
    <Console name="Stdout" target="SYSTEM_OUT">
      <PatternLayout pattern="${coloredPattern}"/>
    </Console>
    <RollingFile name="Logfile" fileName="${fileName}" filePattern="${filePattern}">
      <PatternLayout pattern="${rawPattern}"/>
      <Policies>
        <SizeBasedTriggeringPolicy size="1 MB"/>
      </Policies>
      <MyRolloverStrategy fileIndex="min" max="16"/>
    </RollingFile>
  </Appenders>
  <Loggers>
    <Root level="info">
      <AppenderRef ref="Stdout"/>
      <AppenderRef ref="Logfile"/>
    </Root>
  </Loggers>
</Configuration>

这是我的滚动策略。java：

package de.jme.toolbox.logging;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.zip.Deflater;

import org.apache.logging.log4j.core.appender.rolling.DefaultRolloverStrategy;
import org.apache.logging.log4j.core.appender.rolling.RollingFileManager;
import org.apache.logging.log4j.core.appender.rolling.RolloverDescription;
import org.apache.logging.log4j.core.appender.rolling.helper.Action;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
import org.apache.logging.log4j.core.config.plugins.PluginConfiguration;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.apache.logging.log4j.core.helpers.Integers;
import org.apache.logging.log4j.core.lookup.StrSubstitutor;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.status.StatusLogger;

/**
 * Own RolloverStrategy to hook the DefaultRolloverStrategy's rollover events
 *
 * Siehe auch:
 * - https://issues.apache.org/jira/browse/LOG4J2-486
 * - http://apache-logging.6191.n7.nabble.com/log4j2-getting-started-amp-rolling-files-tt8406.html#a42402
 * - http://stackoverflow.com/questions/20819376/log4j2-rollingfile-appender-add-custom-info-at-the-start-of-each-logfile
 *
 * @author Joe Merten
 */
@org.apache.logging.log4j.core.config.plugins.Plugin(name="MyRolloverStrategy", category="Core", printObject=true)
public class MyRolloverStrategy extends DefaultRolloverStrategy {

    protected static final Logger logger = StatusLogger.getLogger();

    // ==============================
    // ↓↓↓ Some stuff copied from ↓↓↓
    // https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk/log4j-core/src/main/java/org/apache/logging/log4j/core/appender/rolling/DefaultRolloverStrategy.java r1556050
    // Just changed »DefaultRolloverStrategy« to »MyRolloverStrategy«

    private static final int MIN_WINDOW_SIZE = 1;
    private static final int DEFAULT_WINDOW_SIZE = 7;

    @PluginFactory
    public static MyRolloverStrategy createStrategy(
            @PluginAttribute("max") final String max,
            @PluginAttribute("min") final String min,
            @PluginAttribute("fileIndex") final String fileIndex,
            @PluginAttribute("compressionLevel") final String compressionLevelStr,
            @PluginConfiguration final Configuration config) {
        final boolean useMax = fileIndex == null ? true : fileIndex.equalsIgnoreCase("max");
        int minIndex;
        if (min != null) {
            minIndex = Integer.parseInt(min);
            if (minIndex < 1) {
                LOGGER.error("Minimum window size too small. Limited to " + MIN_WINDOW_SIZE);
                minIndex = MIN_WINDOW_SIZE;
            }
        } else {
            minIndex = MIN_WINDOW_SIZE;
        }
        int maxIndex;
        if (max != null) {
            maxIndex = Integer.parseInt(max);
            if (maxIndex < minIndex) {
                maxIndex = minIndex < DEFAULT_WINDOW_SIZE ? DEFAULT_WINDOW_SIZE : minIndex;
                LOGGER.error("Maximum window size must be greater than the minimum windows size. Set to " + maxIndex);
            }
        } else {
            maxIndex = DEFAULT_WINDOW_SIZE;
        }
        final int compressionLevel = Integers.parseInt(compressionLevelStr, Deflater.DEFAULT_COMPRESSION);
        return new MyRolloverStrategy(minIndex, maxIndex, useMax, compressionLevel, config.getStrSubstitutor());
    }
    // ↑↑↑ Some stuff copied from ↑↑↑
    // ==============================

    protected MyRolloverStrategy(int minIndex, int maxIndex, boolean useMax, int compressionLevel, StrSubstitutor subst) {
        super(minIndex, maxIndex, useMax, compressionLevel, subst);
    }

    // Wrapper class only for setting a hook to execute()
    static class MyAction implements Action {
        final Action delegate;
        final String fileName;

        public MyAction(final Action delegate, final String fileName) {
            this.delegate = delegate;
            this.fileName = fileName;
        }

        @Override public void run() {
            delegate.run();
        }

        @Override public boolean execute() throws IOException {
            try {
                BufferedWriter writer = null;
                try {
                    writer = new BufferedWriter(new FileWriter(new File(fileName), true));
                    writer.write("****************************\n");
                    writer.write("*** Bye, bye old logfile ***\n");
                    writer.write("****************************\n");
                } finally {
                    if (writer != null)
                        writer.close();
                }
            } catch (Throwable e) {
                logger.error("Writing to bottom of old logfile \"" + fileName + "\" with", e);
            }

            boolean ret = delegate.execute();

            try {
                BufferedWriter writer = null;
                try {
                    writer = new BufferedWriter(new FileWriter(new File(fileName), true));
                    writer.write("*************************\n");
                    writer.write("*** Hello new logfile ***\n");
                    writer.write("*************************\n");
                } finally {
                    if (writer != null)
                        writer.close();
                }
            } catch (Throwable e) {
                logger.error("Writing to top of new logfile \"" + fileName + "\" with", e);
            }

            return ret;
        }

        @Override public void close() {
            delegate.close();
        }

        @Override public boolean isComplete() {
            return delegate.isComplete();
        }
    }

    // Wrapper class only for setting a hook to getSynchronous().execute()
    static class MyRolloverDescription implements RolloverDescription {
        final RolloverDescription delegate;

        public MyRolloverDescription(final RolloverDescription delegate) {
            this.delegate = delegate;
        }

        @Override public String getActiveFileName() {
            return delegate.getActiveFileName();
        }

        @Override public boolean getAppend() {
            //return delegate.getAppend();
            // As long as we already put some data to the top of the new logfile, subsequent writes should be performed with "append".
            return true;
        }

        // The synchronous action is for renaming, here we want to hook
        @Override public Action getSynchronous() {
            Action delegateAction = delegate.getSynchronous();
            if (delegateAction == null) return null;
            return new MyAction(delegateAction, delegate.getActiveFileName());
        }

        // The asynchronous action is for compressing, we don't need to hook here
        @Override public Action getAsynchronous() {
            return delegate.getAsynchronous();
        }
    }

    public RolloverDescription rollover(final RollingFileManager manager) {
        RolloverDescription ret = super.rollover(manager);
        return new MyRolloverDescription(ret);
    }
}

如果我发布的功能请求能够实现，在log4j2的未来版本中解决这个要求可能会更容易。