Arthas, a sharp tool for online diagnosis - several important commands

 

Catalog

1： Write in the front

2： install

3： A detailed explanation of common orders

3.1：jvm 

3.2：trace （ Time consuming ）

3.3：watch（ View parameters ）

3.4：stack 

3.5：tt

4： summary

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1： Write in the front

Are you still worried about online problems ？

Are you still upset that there is no print log online and the log is republished again ？

Are you still suffering from the headache of working inefficiently for some reason ？

Next, we will introduce an open-source online diagnostic tool from Alibaba --Arthas. After my own test, the leather is really , Love the , Love the .

 

2： install

        At present, only for macos perhaps centos Environmental Science , Installation steps

1： Use  wget https://alibaba.github.io/arthas/arthas-boot.jar Download

2： Use java -jar To start the jar      java -jar arthas-boot.jar

3： Select the previous 1,2,3 Conduct attach To the corresponding app in , Like mine here app yes ArthasTestApplication, So I choose 3, And then go back

In this way, it is easy to enter arthas The connection corresponds to app The interface of .

3： A detailed explanation of common orders

3.1：jvm 

You can see the current jvm Some of the parameters in it , Including important indicators ,GC The number and time of , Not the point of this article

3.2：trace （ Time consuming ）

grammar ：trace  Fully qualified class name Method name   =======>  trace com.zcc.arthastest.TestController getUser 

You can view the call stack of the primary interface , Which interfaces take more time , At present, the official style is marked with red .

Obviously in the screenshot , This method is used 3003.885282 It takes a lot of time , And in #19 That's ok , I found that thread hibernation occurred in the code , This shows that you can optimize .

3.3：watch（ View parameters ）

  For us, there is no online reference , Return parameters , The exception thrown , Where is it excluded , And then he looked confused , Do you have 10000 drafts in mind , Now don't panic , A few simple commands can help you solve the problem easily .

1： Check the input parameters

watch -b  Fully qualified class name Method name   params   =======>  watch -b com.zcc.arthastest.TestController getUser  params

In the screenshot, it is obvious that the intercepted input parameters have been typed

2： View output parameters

command ：watch Fully qualified class name Method name   "{params, returnObj, throwExp}"  ====== >

watch com.zcc.arthastest.TestController getUser "{params, returnObj, throwExp}"

3： View outliers

The command is the same as that of the view parameter , The following is a direct demonstration , When the input parameter ==1 When , It throws an exception

watch Fully qualified class name Method name   "{params, returnObj, throwExp}"  ====== >

watch com.zcc.arthastest.TestController getUser "{params, returnObj, throwExp}"

3.4：stack 

View the call stack and java Kit comes with jstack It's about the same , Is to view the call stack of the thread .

command ：stack Fully qualified class name   Method name =======> stack com.zcc.arthastest.TestController getUser

3.5：tt

tt -t com.zcc.arthastest.TestController getUser

You can also add -n Parameters   

tt -t  -n 3 com.zcc.arthastest.TestController getUser Three times will exit , Prevent too many calls , It's hard to find

The legendary time and space tunnel , You can view the record of interface calls , And replay , This is really too fierce .

Interface playback ：

1： First use tt -l  Look at the list

2： Select a index To play back

command ： tt -i 1000 -p

The playback index = 1000 Of

The playback index = 1010 Of

 

4： summary

Only this and nothing more Arthas This is the brief introduction of , Under the supplement , Now many companies basically use docker Or based on docker The deployment of , Actually Arthas That's one jar nothing more , Put it completely in dockerFIle To build a container together , Otherwise, you have to download it again every time you release it , This is embarrassing , This jar Not much , The cost is not very high . As long as DockerFile Add a line of code to --- Lu Xun told you that big trees can enjoy the cool , But I didn't tell you how to find the big tree . If there are any bad points in the above, please guide and exchange .

4： The attachment

      This chapter tests the code address ：https://gitee.com/htmonitor/arthas.git