auto-installation

[stevengj]

You should probably be doing something like pyimport_conda("sgp4", "sgp4") in your __init__ function to auto-install the SGP4 package via Conda if possible. (Requires PyCall 1.5.)

Though it looks like sgp4 is only available in a custom Conda channel. To make this possible, I'll add a third argument to pyimport_conda in PyCall 1.6 so that you can do pyimport_conda("sgp4", "sgp4", "poliastro") to use the poliastro channel.

[stevengj]

Okay, PyCall 1.6 should be tagged shortly, and then you can automate installation via pyimport_conda("sgp4", "sgp4", "poliastro")

[crbinz]

Finally got around to this -- that was easy! Thanks.

[stevengj]

I would recommend something like what the PyCall README says:

const sgp4io = PyNULL()
const earth_gravity = PyNULL()
function __init__()
    copy!(sgp4io, pyimport_conda("sgp4.io", "sgp4", "poliastro"))
    copy!(earth_gravity, pyimport("sgp4.earth_gravity"))
end

and then you can do e.g. twoline2rv(args...) = sgp4io["twoline2rv"](args...) and GravityModel(ref::AbstractString) = earth_gravity["ref"].

This is more type-stable and should also be faster because you don't need to have pywrap convert every single object defined in the module.

Note also that pyimport_conda already gives a useful error message, so you don't need your own.

[crbinz]

Awesome, thanks for the tips.