Arthas case: dynamic update application logger level

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source ： case-ognl-update-logger-level

Case study : dynamic to update application Logger Level

In this case , Dynamically modify the applied Logger Level.

lookup UserController Of ClassLoader

sc -d com.example.demo.arthas.user.UserController | grep classLoaderHash

$ sc -d com.example.demo.arthas.user.UserController | grep classLoaderHash
 classLoaderHash   1be6f5c3

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use ognl obtain logger

ognl –classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader ‘@[email protected]’

$ ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@[email protected]'
@Logger[
    [email protected][5454405123156820674],
    [email protected][ch.qos.logback.classic.Logger],
    [email protected][com.example.demo.arthas.user.UserController],
    level=null,
    [email protected][20000],
    [email protected][Logger[com.example.demo.arthas.user]],
    childrenList=null,
    aai=null,
    [email protected][true],
    [email protected][ch.qos.logback.classic.LoggerContext[default]],
]

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You can know [email protected] The actual use is logback. You can see level=null, The actual final level It's from root logger From inside .

Set separately UserController Of logger level

ognl –classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader ‘@[email protected](@[email protected])’

Once again [email protected], We can see that it is DEBUG 了 ：

ognl –classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader ‘@[email protected]’

$ ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@[email protected]'
@Logger[
    [email protected][5454405123156820674],
    [email protected][ch.qos.logback.classic.Logger],
    [email protected][com.example.demo.arthas.user.UserController],
    [email protected][DEBUG],
    [email protected][10000],
    [email protected][Logger[com.example.demo.arthas.user]],
    childrenList=null,
    aai=null,
    [email protected][true],
    [email protected][ch.qos.logback.classic.LoggerContext[default]],
]

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modify logback Overall situation logger level

ognl –classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader ‘@[email protected](“root”).setLevel(@[email protected])’

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