Maven plugin: support headless execution of recorder's HAR mode

[chriskilding]

Proposal

I would like the Maven plugin to allow headless execution of the recorder target in HAR mode.

To that end the following options come to mind:

Add missing properties to recorder target

Add the missing HAR-related properties from ArgsParser to RecorderMojo:

• mode (enum: proxy or har)
• headless (boolean)
• harFilePath (path)

Define different recorder targets for proxy mode and HAR mode

Each target would have the options that make sense for it.

Questions

This feature also questions a couple of the assumptions made by the existing Maven plugin recorder options, which I think are largely designed for the point-and-click proxy mode use case.

• The scenarios are generated in src/test/scala, but the usage I'm proposing implies generated code that we may not want to commit. Perhaps we need a convention for Gatling codegen in the target directory (which is not in version control).
• The recorder currently only supports a single HAR file. I would ideally like to convert a directory of HAR files, whose names I may not know ahead of time. Can the harFilePath option support /* globbing to grab multiple files?

Checklist

Make sure these checkboxes are checked before submitting your issue. Thanks you!

[slandelle]

What are you trying to do exactly? The raw result of an HAR conversion needs to be edited to fix correlation, inject dynamic data...

[chriskilding]

Hi Stephane,

We've got a bunch of HAR files which are generated from our instrumentation, and are looking to improve the automation in turning them into something Gatling-friendly.

As you say, we expect to do a bit of editing on the generated scenarios so we're not looking for total automation, just 'a bit more' automation by filling in the gaps in the Maven plugin. So that we can bulk convert a directory of HAR files to a bunch of Gatling scenarios, which we can then edit as needed. (Rather than point-and-click in the recorder UI for each one.)

[slandelle]

Perhaps we need a convention for Gatling codegen in the target directory (which is not in version control).

That doesn't look like a good idea to me. Generated source dirs usually look like src/(main|test)/generated or similar and you then have to play with maven configuration to make it picked by compilation goal.

Anyway, this looks pretty complicated with lots of steps, with some of them not performed by Gatling.
Moreover, I tend to refrain from shipping features that wouldn't have a widespread usage.
I'd like to see some more demand for this.

[chriskilding]

That's fair, we can leave out that bit of the feature request for now.

[chriskilding]

Thoughts on whether there should be a single recorder target + mode enum argument for both modes, or one target for each?

[slandelle]

@chriskilding Sorry, I don't follow.

[chriskilding]

If we keep a single recorder target, the RecorderMojo would have to do double duty for Proxy mode and Har mode, taking the union of their arguments, and we would have to allow the user to toggle which mode they want with something like <mode>proxy</mode> or <mode>har</mode>.

If we have two targets, each Mojo would only need to take the arguments that the relevant mode requires, and we would not need a mode enum. For example gatling:recorder and gatling:converter.

[slandelle]

Let's go with one single mojo for consistency so we keep on talking about the Recorder in proxy or har mode.

[slandelle]

@chriskilding Any update?

[albertoSoto]

Is it any update in this headless execution? I can't understand why the recorder allows the conversion with the GUI but there is no way to automate via maven plugin. I have been able to check the documentation and headless mode is documented as stated https://gatling.io/docs/gatling/reference/current/http/recorder/#headless-mode, but maven plugin seems to do not support it, as the output of mvn gatling:help -Ddetail=true -Dgoal=recorder does not show any option.

Picking up the recorder.conf file seems to fail there, although I have tried with the following to inject it.

mvn gatling:recorder -Dgatling.recorder.simulationsFolder="output" -Dgatling.configFolder=""

I am really interested in place the e2e tests from cucumber, which can generate HAR files, to use with Gatling. Thanks in advance.

[slandelle]

I can't understand why the recorder allows the conversion with the GUI but there is no way to automate via maven plugin.

I am really interested in place the e2e tests from cucumber, which can generate HAR files, to use with Gatling. Thanks in advance.

Executing under load the raw traffic generated from one single user is broken: you're going to test your caches (same database records, application caches, etc) and are going to get super good results that are actually not valid compared to the actual traffic.
You must introduce at least test data so your virtual users use the caches in a realistic way, which typically requires some manual edition.

[albertoSoto]

I think I have explained too badly my use case:
I have set of e2e tests that want to dynamize, but using HAR conversion from the recorder, seem to be a very good base to automate the workload (as there ir an interface for using it with recorder already)

Unfortunately, I don't see how to execute the headless conversion from HAR files from Maven. Is nothing related to a single user, but to have a base to dynamize it. Otherwise, there is a need to re-code, all the steps on the, for instance, Cucumber pipeline.

HAR conversion works under GUI for Gatling recorder, but I can't convert with maven. The injection for dynamic conf files does not work when you use

mvn gatling:recorder -Dgatling.configFolder="-any-"

The base recorder.conf file can be found https://github.com/gatling/gatling/blob/main/gatling-recorder/src/main/resources/recorder-defaults.conf and a copy from it has been introduce in the project, but anyway, it ignores to run on headless via maven execution.

Is this a usage problem? I can also see that file named recorder.conf does not get packaged in the target folder.
Thank you very much

PD: As a reminder, Current mvn plugin options for mojo executer are:

gatling:recorder
Mojo to run Gatling Recorder.
Available parameters:

• className
• configFolder (Default: ${project.basedir}/src/test/resources)
  User property: gatling.configFolder
• encoding
• followRedirect
• localPort
• packageName (Default: ${project.groupId})
• proxyHost
• proxyPort
• proxySSLPort
• resourcesFolder (Default: ${project.basedir}/src/test/resources)
• simulationsFolder