2 Replies Latest reply on Feb 7, 2018 5:03 AM by ochaloup

    Accessible method for injecting Byteman agent to current JVM

    ochaloup
    ochaloup Feb 2, 2018 3:27 AM

      Hi adinn,

       

      as I was playing with dtest library a bit I was thinking it could be beneficial to have some java utility method somewhere in Byteman that give me chance to install Byteman agent to the currently running JVM. It's for purpose of writing tests with use of dtest, I mean.

      This is done already in `bmunit` (byteman/BMUnitConfigState.java at master · bytemanproject/byteman · GitHub ) but it's internal to it only. Do you think having that visible in general would be feasible? Or if, that should be made responsibility of the contrib module itself and you think e.g. kind of duplication the code to internals of dtest would be better?

       

      Thanks

      Ondra

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        • 1. Re: Accessible method for injecting Byteman agent to current JVM
          adinn
          adinn Feb 6, 2018 11:36 AM (in response to ochaloup)

          Hi Ondra,

           

          Thanks for asking about this. It's a good question.

           

          One of the reasons the agent self-install code is in BMUnit but not in the agent jar itself (byteman.jar) is that it can only be compiled & invoked with a dependency on bminstall.jar. Now, byteman.jar cannot depend on bminstall.jar. For a start, the former may get hoisted into the bootstrap classpath while the latter still remains in the system classpath.

           

          The BMUnit code you are interested in is mostly a fairly thin wrapper around an API provided by class Install. However, it does include some useful stuff to propagate configuration settings to Install and, more importantly, work out the current process id. It might well make sense to migrate a little bit of that BMUnit code down into Install and/or provide an alternative API to access the Install functionality.

           

          If you can think of a way to retain compatibility for existing BMUnit functionality while exposing a more easy to use API from the bminstall jar then I'll be happy to consider pushing the necessary changes. If you need advice or are finding it hard to get right then I can also look into it. Raise a JIRA and propose a fix!

           

          regards,

           

           

          Andrew Dinn

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