Add Andor camera service

[ivalaginja]

Add a service for an Andor camera, here specifically with tests on a Neo so other Andor cameras that use the same SDK might or might not work with this.

Very much WIP, for now just a mostly bare bones structure.

Fixes #135

[ivalaginja]

Our new PC got delivered way, way faster than anticipated, so I will be working on this PR with a higher urgency now.

I realized that it might be easiest to just use a Python package that provides a wrapper around the Andor SDK instead of trying to write the relevant pieces myself.

Googling gave me a couple of different options:
https://github.com/hamidohadi/pyandor
https://github.com/ardiloot/PyAndor
https://gitlab.com/ptapping/andor3
https://github.com/PyMoDAQ/pymodaq_plugins_andor

The first one seems the simplest, but it was not released either to PyPI or any conda channel, so we'd be relying on a GitHub repository only, which is not ideal. If it proves being the simplest/best solution I might still go for it, since the Andor Neo sCMOS camera that THD2 uses has recently been discontinued (it's not being sold anymore), and THD2 will be changing its main camera early next year anyway. Not sure how good it would be to merge a PR relying on this though.

Both the first and second one turn out to only work with the older Andor cameras and SDK2, while the Neo uses SDK3, so these options are out the window.

Both of the last two options support SDK3, I checked before continuing. Both also support Windows and Linux, not MacOS, which is fine since it's not expected to run any hardware components from MacOS, and a simulated services does not have to connect to the SDK.

The fourth library is a plugin for PyMoDAQ, a Python library sponsored by the CNRS for laboratory equipment. While it is regularly maintained, it is unclear to me how much it depends on the PyMoDAQ package itself, while option 3 listed above is completely independent and released on PyPI - so I am leaning towards option 3.

The best way forward will be for me to install andor3 on our machine and try to control the camera with that directly. If this works fine, I can start thinking about how to build the hardware service around.

@ehpor, does that make sense?

[a-sevin]

For my point of view, all the codes inside hardware is independent from PyMoDAQ

[ivalaginja]

@a-sevin does that mean that PyMoDAQ plugins can be installed independently of the main library as well? It would be overkill to have that full library as a dependency if we just need one of the plugins I think.
Also, do you see any substantial difference in the actual code of the two options? To me they seem like they're doing the same thing.

[a-sevin]

My first Thought was to copying the code and keeping the IP, copyright and license but... It's under GPL... So, I don't know if we can grab a part of a program GPL under BSD...
not really in fact: https://opensource.stackexchange.com/a/39

[ivalaginja]

@ehpor I just saw that the camera object Andor3 from andor3 calls the "open" call in its init already. From what I see in the other cameras in catkit2, this is not how it's done there. Does this pose a problem?

[ehpor]

@ivalaginja

@ehpor I just saw that the camera object Andor3 from andor3 calls the "open" call in its init already. From what I see in the other cameras in catkit2, this is not how it's done there. Does this pose a problem?

In principle that's not a problem. But, since there is some communication done at the end of __init__() with the testbed server, I prefer to have any code that might crash in the open() method. That ensures that log messages are actually passed around correctly, making debugging easier. Why can't you create the Andor3 object inside Service.open()?

[ehpor]

@ivalaginja

The best way forward will be for me to install andor3 on our machine and try to control the camera with that directly. If this works fine, I can start thinking about how to build the hardware service around.

Yes, both the andor3 library and PyMoDAQ seem like standard ctypes code, so that's unlikely to cause many problems. I'd choose andor3 for the time being, since it's a more focussed package.

[ivalaginja]

Why can't you create the Andor3 object inside Service.open()?

@ehpor I can, I simply haven't thought of it! 😄 Thanks for the guidance!

[ivalaginja]

@ehpor I think this is at a point where I would love some feedback if you have some time. I have managed to make the API calls work on our machine although I still have some stuff to figure out with the buffers and the acquisition, but I am getting there.
What I am most unsure about are the properties, I forgot - there are the Python object properties created with their getters and setters, but there are also the (same) ones created with the service method make_property() - what does what again, what exposes what where?

[ivalaginja]

This package also needs numba, which it doesn't install automatically. I need to add it to the env file.

[ivalaginja]

I am having memory issues on the PC I am testing this on, likely to a faulty installation of the library. I will wait for the new PC to be in the clean room and then try it on there.

[ivalaginja]

This PR is not needed from our side anymore.