目录
# logger
提示
查看 logger 信息,更新 logger level
# 使用参考
# 查看所有 logger 信息
以下面的logback.xml
为例:
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<appender name="APPLICATION" class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>app.log</file>
<rollingPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy">
<fileNamePattern>mylog-%d{yyyy-MM-dd}.%i.txt</fileNamePattern>
<maxFileSize>100MB</maxFileSize>
<maxHistory>60</maxHistory>
<totalSizeCap>2GB</totalSizeCap>
</rollingPolicy>
<encoder>
<pattern>%logger{35} - %msg%n</pattern>
</encoder>
</appender>
<appender name="ASYNC" class="ch.qos.logback.classic.AsyncAppender">
<appender-ref ref="APPLICATION" />
</appender>
<appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
<encoder>
<pattern>%-4relative [%thread] %-5level %logger{35} - %msg %n
</pattern>
<charset>utf8</charset>
</encoder>
</appender>
<root level="INFO">
<appender-ref ref="CONSOLE" />
<appender-ref ref="ASYNC" />
</root>
</configuration>
使用logger
命令打印的结果是:
[arthas@2062]$ logger
name ROOT
class ch.qos.logback.classic.Logger
classLoader sun.misc.Launcher$AppClassLoader@2a139a55
classLoaderHash 2a139a55
level INFO
effectiveLevel INFO
additivity true
codeSource file:/Users/hengyunabc/.m2/repository/ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar
appenders name CONSOLE
class ch.qos.logback.core.ConsoleAppender
classLoader sun.misc.Launcher$AppClassLoader@2a139a55
classLoaderHash 2a139a55
target System.out
name APPLICATION
class ch.qos.logback.core.rolling.RollingFileAppender
classLoader sun.misc.Launcher$AppClassLoader@2a139a55
classLoaderHash 2a139a55
file app.log
name ASYNC
class ch.qos.logback.classic.AsyncAppender
classLoader sun.misc.Launcher$AppClassLoader@2a139a55
classLoaderHash 2a139a55
appenderRef [APPLICATION]
从appenders
的信息里,可以看到
CONSOLE
logger 的 target 是System.out
APPLICATION
logger 是RollingFileAppender
,它的 file 是app.log
ASYNC
它的appenderRef
是APPLICATION
,即异步输出到文件里
# 查看指定名字的 logger 信息
[arthas@2062]$ logger -n org.springframework.web
name org.springframework.web
class ch.qos.logback.classic.Logger
classLoader sun.misc.Launcher$AppClassLoader@2a139a55
classLoaderHash 2a139a55
level null
effectiveLevel INFO
additivity true
codeSource file:/Users/hengyunabc/.m2/repository/ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar
# 查看指定 classloader 的 logger 信息
注意 hashcode 是变化的,需要先查看当前的 ClassLoader 信息,提取对应 ClassLoader 的 hashcode。
如果你使用-c
,你需要手动输入 hashcode:-c <hashcode>
[arthas@2062]$ logger -c 2a139a55
name ROOT
class ch.qos.logback.classic.Logger
classLoader sun.misc.Launcher$AppClassLoader@2a139a55
classLoaderHash 2a139a55
level DEBUG
effectiveLevel DEBUG
additivity true
codeSource file:/Users/hengyunabc/.m2/repository/ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar
appenders name CONSOLE
class ch.qos.logback.core.ConsoleAppender
classLoader sun.misc.Launcher$AppClassLoader@2a139a55
classLoaderHash 2a139a55
target System.out
name APPLICATION
class ch.qos.logback.core.rolling.RollingFileAppender
classLoader sun.misc.Launcher$AppClassLoader@2a139a55
classLoaderHash 2a139a55
file app.log
name ASYNC
class ch.qos.logback.classic.AsyncAppender
classLoader sun.misc.Launcher$AppClassLoader@2a139a55
classLoaderHash 2a139a55
appenderRef [APPLICATION]
对于只有唯一实例的 ClassLoader 可以通过--classLoaderClass
指定 class name,使用起来更加方便:
logger --classLoaderClass sun.misc.Launcher$AppClassLoader
- 注: 这里 classLoaderClass 在 java 8 是 sun.misc.Launcher$AppClassLoader,而java 11的classloader是jdk.internal.loader.ClassLoaders$AppClassLoader。
--classLoaderClass
的值是 ClassLoader 的类名,只有匹配到唯一的 ClassLoader 实例时才能工作,目的是方便输入通用命令,而-c <hashcode>
是动态变化的。
# 更新 logger level
[arthas@2062]$ logger --name ROOT --level debug
update logger level success.
# 指定 classloader 更新 logger level
默认情况下,logger 命令会在 SystemClassloader 下执行,如果应用是传统的war
应用,或者 spring boot fat jar 启动的应用,那么需要指定 classloader。
可以先用 sc -d yourClassName
来查看具体的 classloader hashcode,然后在更新 level 时指定 classloader:
[arthas@2062]$ logger -c 2a139a55 --name ROOT --level debug
# 查看没有 appender 的 logger 的信息
默认情况下,logger
命令只打印有 appender 的 logger 的信息。如果想查看没有appender
的 logger 的信息,可以加上参数--include-no-appender
。
注意,通常输出结果会很长。
[arthas@2062]$ logger --include-no-appender
name ROOT
class ch.qos.logback.classic.Logger
classLoader sun.misc.Launcher$AppClassLoader@2a139a55
classLoaderHash 2a139a55
level DEBUG
effectiveLevel DEBUG
additivity true
codeSource file:/Users/hengyunabc/.m2/repository/ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar
appenders name CONSOLE
class ch.qos.logback.core.ConsoleAppender
classLoader sun.misc.Launcher$AppClassLoader@2a139a55
classLoaderHash 2a139a55
target System.out
name APPLICATION
class ch.qos.logback.core.rolling.RollingFileAppender
classLoader sun.misc.Launcher$AppClassLoader@2a139a55
classLoaderHash 2a139a55
file app.log
name ASYNC
class ch.qos.logback.classic.AsyncAppender
classLoader sun.misc.Launcher$AppClassLoader@2a139a55
classLoaderHash 2a139a55
appenderRef [APPLICATION]
name com
class ch.qos.logback.classic.Logger
classLoader sun.misc.Launcher$AppClassLoader@2a139a55
classLoaderHash 2a139a55
level null
effectiveLevel DEBUG
additivity true
codeSource file:/Users/hengyunabc/.m2/repository/ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar
name com.alibaba
class ch.qos.logback.classic.Logger
classLoader sun.misc.Launcher$AppClassLoader@2a139a55
classLoaderHash 2a139a55
level null
effectiveLevel DEBUG
additivity true
codeSource file:/Users/hengyunabc/.m2/repository/ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar
...