Byteman Fluent API

[Davide D'Alto]

Hi,

I wanted to try Byteman and so I started a very simple prototype for the fluent API (https://issues.jboss.org/browse/ARQ-355):

https://github.com/DavideD/arquillian-extension-byteman/tree/BM-ARQ-355

It's still at a very early stage. Rules are registered at class level and at the moment it is possible to do something like this:

{code}

Descriptors.create(BytemanRuleDescriptor.class)

               .rule("Throw exception on success")

               .classMatch("StatelessManagerBean")

               .methodMatch("forcedMethodLevelFailure")

               .ifCondition("TRUE")

               .doAction("debug(\"intercepted\""))

               .doAction("throw new java.lang.RuntimeException(\"BYTEMAN\")")

{code}

I don't understand how to filter for the target container. How can I obtain the target container?

Feedback is appreciated.

Cheers,

Davide

[Aslak Knutsen]

Hi Davide, cool stuff.. At a conference at the moment so I'll look at it in more detail when I get back.

Support for targeting a specific container is currently lacking from the extension.

(there is a onducomented feature of adding a file called byteman.scipt in the Deployment cp which will get picked up but..

[Davide D'Alto]

Thanks,

I'm not sure on how to use that though.

Another issue that I have at the moment with this is when I start two containers. The Byteman agent seems to connect only on the first one.

By the way, I've noticed that in the RuleInstaller (https://github.com/arquillian/arquillian-extension-byteman/blob/master/src/main/java/org/jboss/arquillian/extension/byteman/impl/container/RuleInstaller.java#L48), the method

uninstallClass is actually calling SubmitUtil.install(...).

Is it correct?

[Aslak Knutsen]

Davide D\'Alto wrote:

Another issue that I have at the moment with this is when I start two containers. The Byteman agent seems to connect only on the first one.

By the way, I've noticed that in the RuleInstaller (https://github.com/arquillian/arquillian-extension-byteman/blob/master/src/main/java/org/jboss/arquillian/extension/byteman/impl/container/RuleInstaller.java#L48), the method

uninstallClass is actually calling SubmitUtil.install(...).

Is it correct?

No, that's a copy paste error.

[Aslak Knutsen]

To my knowledge the top level in byteman is a Script, and a script can contian multiple rules. Not sure you can insert just a Rule, or if that Rule has to be a single Rule in a Script.

I think it would fit better the have it named BytemanScriptDescriptor

Descriptors.create(BytemanScriptDescriptor.class)
  .rule(name)
    .classMatch()
    .methodMatch()
  .rule(otherName)
    ....

It's a bit clunky to have to escape the ", not sure what Byteman allows here, but we could allow single quotes and replace them as double if Byteman only allow double.

.doAction("debug('intercepted')")

[Aslak Knutsen]

Davide D\'Alto wrote:

Another issue that I have at the moment with this is when I start two containers. The Byteman agent seems to connect only on the first one.

https://issues.jboss.org/browse/ARQ-908

[Davide D'Alto]

It's a bit clunky to have to escape the ", not sure what Byteman allows here, but we could allow single quotes and replace them as double if Byteman only allow double.

.doAction("debug('intercepted')")

That should work.

I was thinking to add some more specfic method related to the allowed actions in Bytema:

doAction(...) is a generic one but we could have doThrow(...), doDebug(..),  doTraceln(...) and so on.

Aslak Knutsen wrote:

To my knowledge the top level in byteman is a Script, and a script can contian multiple rules. Not sure you can insert just a Rule, or if that Rule has to be a single Rule in a Script.

I think it would fit better the have it named BytemanScriptDescriptor

+1

[Davide D'Alto]

Hi,

I've applyed the changes you've suggested:

- Renaming

- String parsing

Single quote are now replaced in action, binding and if. A double single quote is used as escaped of a single quote.

I've added a method in the fluent API to disable the parsing of the string.

https://github.com/DavideD/arquillian-extension-byteman/commits/ARQ-355

Cheers,

Davide