Log4j2 Cron与Size触发策略组合日志日期异常及轮转停止问题

使用的Log4j2依赖 #

<properties>
    <jdkVersion>1.8</jdkVersion>
    <log4jVersion>2.17.1</log4jVersion>
</properties>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-api</artifactId>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-web</artifactId>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-slf4j-impl</artifactId>
</dependency>

Log4j2配置 #

<Properties>
    <Property name="baseDir">${env:APP_HOME}/logs/${web:contextPath}</Property>
    <Property name="filename">${baseDir}/DeviceManagement.log</Property>
    <Property name="filePattern">${baseDir}/DeviceManagement-%d{yyyy-MM-dd}-%i.log</Property>
    <Property name="layoutPattern">[%5p][%t][%c.%M():%L][%d{yy/MM/dd HH:mm:ss.SSS}][%4r]%n%m%n</Property>
</Properties>

<Appenders>
    <Appender type="Console" name="STDOUT">
        <Layout type="PatternLayout" pattern="${layoutPattern}"/>
    </Appender>
    <Appender type="RollingFile" name="ROLLING_FILE" fileName="${filename}" 
                filePattern="${filePattern}">
        <Layout type="PatternLayout" pattern="${layoutPattern}"/>
        <Policies>
            <CronTriggeringPolicy schedule="0 0 0 * * ?"/>
            <SizeBasedTriggeringPolicy size="5 MB"/>
        </Policies>
        <DefaultRolloverStrategy max="20">
            <Delete basePath="${baseDir}" maxDepth="2">
                <IfFileName glob="{DeviceLog/*.log,DeviceManagement-*.log}"/>
                <IfLastModified age="P60D">
                    <IfAny>
                        <IfAccumulatedFileSize exceeds="100 MB" />
                        <IfAccumulatedFileCount exceeds="60" />
                    </IfAny>
                </IfLastModified>
            </Delete>
        </DefaultRolloverStrategy>
    </Appender>
</Appenders>

预期结果 #

日志文件应每日午夜轮转，文件名包含当日日期；基于大小的轮转每日最多生成20个文件。

问题现象 #

日期轮转后文件名显示前一天日期而非当日日期；且基于大小的轮转在索引达到20后停止继续轮转，具体文件列表如下：

2024/03/19  AM 02:26         5,246,621 DeviceManagement-2024-03-18-1.log <----3月19日02:26轮转，文件名应为2024-03-19却显示2024-03-18。
2024/03/19  AM 02:54         5,242,886 DeviceManagement-2024-03-18-2.log
2024/03/19  AM 03:21         5,242,887 DeviceManagement-2024-03-18-3.log
2024/03/19  AM 03:50         5,248,627 DeviceManagement-2024-03-18-4.log
2024/03/19  AM 04:20         5,243,058 DeviceManagement-2024-03-18-5.log
2024/03/19  AM 04:50         5,243,757 DeviceManagement-2024-03-18-6.log
2024/03/19  AM 05:21         5,245,418 DeviceManagement-2024-03-18-7.log
2024/03/19  AM 05:52         5,247,493 DeviceManagement-2024-03-18-8.log
2024/03/19  AM 06:25         5,243,024 DeviceManagement-2024-03-18-9.log
2024/03/19  AM 06:56         5,243,052 DeviceManagement-2024-03-18-10.log
2024/03/19  AM 07:29         5,243,677 DeviceManagement-2024-03-18-11.log
2024/03/19  AM 08:02         5,245,473 DeviceManagement-2024-03-18-12.log
2024/03/19  AM 08:31         5,243,077 DeviceManagement-2024-03-18-13.log
2024/03/19  AM 08:54         5,243,030 DeviceManagement-2024-03-18-14.log
2024/03/19  AM 09:07         5,243,012 DeviceManagement-2024-03-18-15.log
2024/03/19  AM 09:20         5,243,273 DeviceManagement-2024-03-18-16.log
2024/03/19  AM 09:43         5,243,066 DeviceManagement-2024-03-18-17.log
2024/03/19  AM 10:06         5,249,359 DeviceManagement-2024-03-18-18.log
2024/03/19  AM 10:28         5,243,121 DeviceManagement-2024-03-18-19.log
2024/03/19  AM 10:47         5,242,932 DeviceManagement-2024-03-18-20.log <-----10:47达到索引20后停止轮转至索引1
2024/03/20  AM 02:11           151,699 DeviceManagement.log <-----当前活跃文件

解决方案 #

1. 日期轮转文件名错误问题 #

默认%d在filePattern中使用的是日志事件发生时间，而非轮转触发时间。午夜轮转时，文件最后一条日志属于前一天，导致文件名用了前一天日期。

修改filePattern，给%d添加{ROLLING_FILE}标记，指定使用轮转触发时间：

<Property name="filePattern">${baseDir}/DeviceManagement-%d{yyyy-MM-dd}{ROLLING_FILE}-%i.log</Property>

2. 大小轮转索引到20后停止问题 #

当前DefaultRolloverStrategy的max="20"是限制所有历史文件总数，而非每日文件数。要实现每日最多20个文件，需调整触发策略和滚动规则：

步骤1：替换触发策略

用TimeBasedTriggeringPolicy替代CronTriggeringPolicy，更适配时间轮转场景，设置interval="1"表示每日轮转：

<Policies>
    <TimeBasedTriggeringPolicy interval="1"/>
    <SizeBasedTriggeringPolicy size="5 MB"/>
</Policies>

步骤2：调整滚动策略

修改DefaultRolloverStrategy，添加fileIndex="nomax"取消全局文件数限制，同时优化Delete规则，按日期分组保留最多20个文件：

<DefaultRolloverStrategy fileIndex="nomax">
    <Delete basePath="${baseDir}" maxDepth="2">
        <IfFileName glob="DeviceManagement-*.log"/>
        <!-- 按每日分组，保留最多20个文件 -->
        <IfAccumulatedFileCount exceeds="20">
            <IfFileName glob="DeviceManagement-${date:yyyy-MM-dd}-*.log"/>
        </IfAccumulatedFileCount>
        <!-- 保留60天内文件，超过则触发删除规则 -->
        <IfLastModified age="P60D">
            <IfAny>
                <IfAccumulatedFileSize exceeds="100 MB" />
                <IfAccumulatedFileCount exceeds="60" />
            </IfAny>
        </IfLastModified>
    </Delete>
</DefaultRolloverStrategy>

最终完整配置 #

<Properties>
    <Property name="baseDir">${env:APP_HOME}/logs/${web:contextPath}</Property>
    <Property name="filename">${baseDir}/DeviceManagement.log</Property>
    <Property name="filePattern">${baseDir}/DeviceManagement-%d{yyyy-MM-dd}{ROLLING_FILE}-%i.log</Property>
    <Property name="layoutPattern">[%5p][%t][%c.%M():%L][%d{yy/MM/dd HH:mm:ss.SSS}][%4r]%n%m%n</Property>
</Properties>

<Appenders>
    <Appender type="Console" name="STDOUT">
        <Layout type="PatternLayout" pattern="${layoutPattern}"/>
    </Appender>
    <Appender type="RollingFile" name="ROLLING_FILE" fileName="${filename}" 
                filePattern="${filePattern}">
        <Layout type="PatternLayout" pattern="${layoutPattern}"/>
        <Policies>
            <TimeBasedTriggeringPolicy interval="1"/>
            <SizeBasedTriggeringPolicy size="5 MB"/>
        </Policies>
        <DefaultRolloverStrategy fileIndex="nomax">
            <Delete basePath="${baseDir}" maxDepth="2">
                <IfFileName glob="DeviceManagement-*.log"/>
                <IfAccumulatedFileCount exceeds="20">
                    <IfFileName glob="DeviceManagement-${date:yyyy-MM-dd}-*.log"/>
                </IfAccumulatedFileCount>
                <IfLastModified age="P60D">
                    <IfAny>
                        <IfAccumulatedFileSize exceeds="100 MB" />
                        <IfAccumulatedFileCount exceeds="60" />
                    </IfAny>
                </IfLastModified>
            </Delete>
        </DefaultRolloverStrategy>
    </Appender>
</Appenders>

内容的提问来源于stack exchange，提问作者Bruce