writing probe for getting function arguments and return

sherkat · Post by **sherkat** » Sun Dec 25, 2022 9:26 am

hi all

i want to get passed args and return value of all invoked methods. i couldn't find any built-in options to do this.
i suppose the only way is to write a custom probe.
can anyone show me a code snippet of doing this?

Post by **Anton Katilin** » Sun Dec 25, 2022 10:00 am

Hi,

Please try using triggers:
https://www.yourkit.com/docs/java/help/triggers.jsp

Add a trigger on method invocation with an action such as "Print Message Invocation Detail" to log to a file or console or "Record Method Invocation" to add events visible in the profiler results.

sherkat · Post by **sherkat** » Sun Dec 25, 2022 1:10 pm

done exactly like the link but im not getting anything; not in the log nor in the YKJP.
im using attach mode
by log i mean the file in the ".yjp\log" folder

Post by **Anton Katilin** » Sun Dec 25, 2022 1:21 pm

Please see the actions which I recommended. They use macros which define what kind of detail is to be logged. The Print* actions allow you to choose the target file.

The simplest way to play with triggers is to connect to a profiled application and compose triggers via the user interface (add trigger, add action) as shown in the help page. You can apply the changes immediately.

You can later export the trigger description to reuse it or apply on start.

sherkat · Post by **sherkat** » Mon Dec 26, 2022 6:12 am

i did as you told:

anything that I'm doing wrong?

Post by **Anton Katilin** » Mon Dec 26, 2022 9:41 am

Sorry I cannot see the image.

sherkat · Post by **sherkat** » Mon Dec 26, 2022 10:28 am

https://ibb.co/2WpHw7z

Post by **Anton Katilin** » Mon Dec 26, 2022 10:51 am

Please specify appropriate method name pattern instead of the placeholder in the trigger properties - see the top node shown on the screenshot you provided.

You have "agentlog" specified. The output will be written to the agent log file <user home>/.yjp/log/<name>-<pid>.log. Please see the other options above the field e.g. to explicitly specify the output file name.

sherkat · Post by **sherkat** » Mon Dec 26, 2022 11:45 am

i know it was a stupid noob question and thanks for coping with that.
now I'm seeing the results in the log file.

sherkat · Post by **sherkat** » Mon Dec 26, 2022 12:27 pm

btw,

im getting this with {@params} :

Code: Select all

22.9-166 4.402: Entering: MyTest:main(java.lang.String[])
  this: MyTest
  params:
    [Ljava.lang.String;@6767c1fc

is there a way to log the array's contents too?(or content of custom objects)

Post by **Anton Katilin** » Tue Dec 27, 2022 9:30 am

Currently this is not possible via a trigger. You should write a custom probe for more sophisticated parameter processing.

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