Adding a custom instrument - Could not find plugin or alias

[hosunhc]

Hi, I've been trying to add an instrument called Perfetto to my WA by following the documentation, without much luck.
Here is the link for info on the instrument Perfetto. I am using their provided helper script.
I just want to start the instrument right before the workload and save the output file into the working directory of the host device. I checked the FAQ, but I think the solution is somewhat different for this case.

In my user directory, I added a directory called perfetto .workload_automation/perfetto/ with three files: perfetto.py, record_android_trace (the helper script), and config.pbtx (a configuration file necessary to run record_android_trace).

So far in perfetto.py, I have:

from wa import Instrument
import subprocess
from signal import SIGINT

class Perfetto(Instrument):
    name = 'perfetto'

    def __init__(self, context):
        super(Perfetto, self).__init__(context)
        self.proc = None

    def start(self, context):
        run_perf = ['./record_android_trace', '-c', 'config.pbtx', '-n', '-o', context.working_directory + 'perfetto.pftrace' ]
        self.proc = subprocess.Popen(run_perf)

    def stop(self, context):
        self.proc.send_signal(SIGINT)

    def finalize(self, context):
        self.proc.terminate()

In .workload_automation/config.yaml, I also added:

extra_plugin_paths: 
- '(home_path)/.workload_automation/perfetto'

And after restarting terminal and running wa create agenda perfetto just to see if wa can read perfetto, I get an error:
ERROR Could not find plugin or alias "perfetto".
I'm assuming I missed a step somewhere or placed the files in the wrong directory, but could not completely able to figure it out after looking through the documentation.
I just want to be able to run record_android_trace before the workload and quit it after and save it into the working directory of the host.
Anyways, any help/suggestions would be appreciated.

[marcbonnici]

Hi,

The easiest way to let WA pick up your instrument should be to place your perfetto directory under (home_path)/.workload_automation/plugins/ and WA should automatically pick it up.

I realize in the "Adding an Instrument" how to we don't explicitly make this clear so we can add a clarification to fix this.

[hosunhc]

Oh I see, I also realized that in the config file, I made an error for extra_plugin_paths: .
Anyways thanks for the quick response.

I tried it and now it's being picked up by WA. However, after running it with wa run config.yaml -f:
ERROR TypeError(Perfetto.__init__() got an unexpected keyword argument 'cleanup_assets').

[marcbonnici]

Ah thanks for finding that, it look like our example is missing the **kwargs argument for the __init__ method.

Could you try changing this to something like

def __init__(self, target, **kwargs):
        super(Perfetto, self).__init__(target, **kwargs)
        self.proc = None

[hosunhc]

Yep works now, thanks a lot!
There was another issue which occurred from context.working_directory, which got fixed with context.output_directory. I think there were some examples here that mistakenly used context.working_directory. Anyways, thanks for everything! Works like a charm.

[marcbonnici]

Thanks for mentioning, I've created a PR (#1202) to address the issues raised.

Please let me know if you come across any other problems.