Delegate emission of "end load" signal to the "SampleChanger" component

[alessandro-olivo]

In the file mxcubeweb/core/components/samplechanger.py I noticed that although the mount_sample_clean_up function emits both the "start" and "end" signals to handle the frontend popup, this doesn’t happen in the "unmount" function, where the "start" signal is emitted BUT the "end" signal is only emitted for "manual" samples so in the other case it's up to the "SC HWO" to emit the "end" signal.

Wouldn’t it make more sense to emit the "end" signal directly from the samplechanger.py also in the unmount_sample_clean_up function ?
Is there something that I'm missing ?

Here my suggested changes (in mxcubeweb/core/components/samplechanger.py) :

def unmount_sample_clean_up(self, sample):
        from mxcubeweb.routes import signals

        try:
            signals.sc_unload(sample["location"])

            if sample["location"] != "Manual":
                HWR.beamline.sample_changer.unload(sample["location"], wait=False)
            else:
                self.set_current_sample(None)
-               signals.sc_load_ready(sample["location"])  
            msg = "[SC] unmounted %s" % sample["location"]
            logging.getLogger("MX3.HWR").info(msg)
        except Exception:
            msg = "[SC] sample could not be mounted"
            logging.getLogger("MX3.HWR").exception(msg)
            raise
        else:
            HWR.beamline.queue_model.mounted_sample = ""
            HWR.beamline.sample_view.clear_all()
+       finally:
+           signals.sc_load_ready(sample["location"])

Thoughts

To be more consistent with the unmount procedure, maybe we should add a new signal, something like this: signals.sc_unload_ready(sample["location"]), instead of the current signals.sc_load_ready(sample["location"])

[marcus-oscarsson]

This code can indeed be improved but I think we in general should be dealing with the signals that comes from the sample changer HardwareObject and remove logic from mxcubeweb/core/components/samplechanger.py (if possible).

Maybe the complication here is rather the separation of handling of manual samples.

Pay attention to that wait is False in the call to unload, meaning that the load might actually not be done (yet), when you reach the finally clause (a bit tricky).

So, a solution could perhaps be to try to remove the separation of manual and "sc" samples and rely entirely on signals.

[marcus-oscarsson]

Thanks for raising this issue, I think it could lead to a nice cleanup !

[alessandro-olivo]

I agree with you. By leaving the responsibility for signal emission to the sample changer HWO, the frontend behavior would better reflect the site’s logic. Furthermore, if we remove the first call signals.sc_unload(sample["location"]), there would no longer be the need to call signals.sc_load_ready(sample["location"]) for manual samples.