H01 interface

[jinhan]

H01 interface based on the latest master branch

• add navis/interfaces/h01.py
• add docs/examples/3_interfaces/plot_04_interface_h01.py

[schlegelp]

Thanks for this PR. I left a few comments above. In particular the docstrings need a bit of work as they still contain references to the MICrONS dataset.

Additionally I have two questions/suggestions:

1. You seem to be using your own CAVE service (global.brain-wire-test.org) and I was wondering whether users had to keep that in mind if they wanted to store their token manually? I'm guessing it changes the name of the secrets file from global.daf-apis.com-cave-secret.json to global.brain-wire-test.org-cave-secret.json? Perhaps you could add a note to the tutorial. I'd use an admonition - something like this:

   !!! note "Saving your token manually"
       If you want to save your token manually, you have to ...

2. There is quite a bit of shared functionality now between the H01 and the MICrONS interface. If you have the appetite for it, it would be nice to refactor a little to reduce code duplication. For example, we could minimally put the _chunks_to_nm and _fetch_single_neuron functions into a cave_utils.py module and re-use them in both h01.py and microns.py:

    └── interfaces
        ├── h01.py 
        ├── microns.py
        └── cave_utils.py  <- put shared functions here

   Most of the other functions could also be put into cave_utils and just thinly wrapped in h01.py. For example:

    def fetch_neurons(
        x,
        *,
        lod=2,
        with_synapses=True,
        datastack="h01_c3_flat",
        parallel=True,
        max_threads=4,
        **kwargs,
    ):
        """Fetch neuron meshes.
        ...
        """
        return cave_utils._fetch_neurons(
            x,
            lod=lod,
            with_synapses=with_synapses,
            datastack=datastack,
            parallel=parallel,
            max_threads=max_threads,
            **kwargs,
        )

None of the above are mission critical and I'm happy to take a stab myself later.

As an aside: unfortunately, the tutorial tests are currently only run on push but not on pull_request. That's my fault - I will fix that once this PR is merged.

[jinhan]

Thank you for the comments.

1. I also found that the H01 interface doesn't need the Auth class. With the H01's server_address, I can create a CAVE client. In addition, I checked that the token is saved in global.brain-wire-test.org-cave-secret.json under the .cloudvolume/secrets folder.

2. I refactored h01.py and microns.py by introducing cave_utils.py, as you suggested.

[schlegelp]

Sorry, I haven't had the time to properly look through the PR yet. Will try to do that in the second half of next week!