背景

公司需要将服务迁移到K8S环境上，由于目前服务输出的格式不符合ES进行采集的日志格式，所有需要将日志输出的格式进行调整为JSON格式，方便ES采集

遇到的坑

之前是直接配置的输出格式的message为"message": %msg"，但是由于打日志需要打印json内容的日志就没有进行转义导致，整体输出的json格式出错，es采集日志就出问题了

解决方法：调整为"message": %enc{%m}{JSON}"则支持json内容输出

参考官方文档：https://logging.apache.org/log4j/2.x/manual/layouts.html#PatternLayout

解决方案-正确姿势

log4j log4j2.xml配置示例

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="OFF">
    <properties>
        <property name="log.pattern">
            {"code":"%X{code}", "time":"%d{MM-dd HH:mm:ss.SSS}", "level":"%level", "method":"%X{method}", "header.client-ip":"%X{header.client-ip}", "header.content-length":"%X{header.content-length}", "thread":"%thread", "class":"%logger{35}:%L", "message": %enc{%m}{JSON}", "stack_trace":"%exception{10}"}\n
        </property>
    </properties>
    <Appenders>
        <Console name="console" target="SYSTEM_OUT">
            <PatternLayout pattern="${log.pattern}"/>
        </Console>
        <RollingRandomAccessFile name="fileLog"
                                 fileName="/home/logs/demo.log"
                                 filePattern="/home/logs/demo.%d{yyyyMMddHH}.log.gz">
            <PatternLayout pattern="${log.pattern}"/>
            <Policies>
                <TimeBasedTriggeringPolicy modulate="true" interval="1"/>
            </Policies>
            <DefaultRolloverStrategy>
                <Delete basePath="data" maxDepth="1">
                    <IfFileName glob="*.log.gz"/>
                    <IfLastModified age="2d"/>
                </Delete>
                <Delete basePath="log" maxDepth="1">
                    <IfFileName glob="*.log.gz"/>
                    <IfLastModified age="2d"/>
                </Delete>
            </DefaultRolloverStrategy>
        </RollingRandomAccessFile>
    </Appenders>

    <Loggers>
        <Root level="debug">
            <AppenderRef ref="console"/>
            <AppenderRef ref="fileLog"/>
        </Root>
        <Logger name="org.springframework.jdbc.core.JdbcTemplate" level="debug"/>
        <Logger name="org.springframework.boot.web.embedded" level="info"/>
    </Loggers>
</Configuration>

定义输出格式

<Properties>
        <property name="log.pattern">
            {"code":"%X{code}", "time":"%d{MM-dd HH:mm:ss.SSS}", "level":"%level", "method":"%X{method}", "header.client-ip":"%X{header.client-ip}", "header.content-length":"%X{header.content-length}", "thread":"%thread", "class":"%logger{35}:%L", "message": %enc{%m}{JSON}", "stack_trace":"%exception{10}"}\n
        </property>
</Properties>

输出格式测试

public class Demo {

    private static final Logger log = LogManager.getLogger();

    public static void main(String[] args) {
        String name = "xiaoming";
        HashMap<String, Object> infoMap = new HashMap<>(3);
        infoMap.put("age", 18);
        infoMap.put("sex", 1);
        infoMap.put("weight", 60);
        log.info("输出信息 name:{}, userInfo:{}", name, JSONObject.toJSONString(infoMap));
    }
}

输出效果：

{"code":"","time":"07-06 11:50:29.429","level":"INFO ","thread":"main","class":"com.tushu.bt.push.web.Demo:24","message": 输出信息 name:xiaoming, userInfo:{\"weight\":60,\"age\":18,\"sex\":1}","stack_trace":""}

会将之前的json格式进行转义操作

图示

踩坑

如果不用"message": %enc{%m}{JSON}"进行处理msg内容直接用"message": %msg"`会出现的问题就是，不会将json内容进行转义导致整体输出的json不是一个正常的json

示例调整输出格式：

<Properties>
        <property name="log.pattern">
            {"code":"%X{code}", "time":"%d{MM-dd HH:mm:ss.SSS}", "level":"%level", "method":"%X{method}", "header.client-ip":"%X{header.client-ip}", "header.content-length":"%X{header.content-length}", "thread":"%thread", "class":"%logger{35}:%L", "message": %msg", "stack_trace":"%exception{10}"}\n
        </property>
</Properties>

还是用上面的Demo.java进行输出日志
效果：

{"code":"", "time":"07-06 12:06:53.483", "level":"INFO", "method":"", "header.client-ip":"", "header.content-length":"", "thread":"main", "class":"com.tushu.bt.push.web.Demo:24", "message": 输出信息 name:xiaoming, userInfo:{"weight":60,"age":18,"sex":1}", "stack_trace":""}

没有进行对message字段进行特殊字符进行转义操作，导致整体输出的json格式出错！