Download dependencies using --platform flag in pip

[thyming]

Currently this project downloads dependencies using pip install, but if you rely on any packages which require a native extension you'll have problems unless you are building from a machine with the same platform (in pip's parlance).

[raymondbutcher]

Hi,

Version 0.11.0 now supports custom build commands (example) which provides a solution to this problem, as you can run any pip commands you want in a custom build script.

But it would be pretty cool if it did this automatically. I wasn't previously aware of the manylinux platform options for pip.

https://github.com/pypa/manylinux
https://blog.zappa.io/posts/zappa-adds-support-for-manylinux-wheels
https://github.com/Miserlou/lambda-packages

Not sure when I'll have time to look into this though.

Cheers!

[thyming]

would you accept a PR changing the platform default to manylinux, simply updating the flags passed to pip? i can't see how this could be less correct than the default right now, which is whatever platform you happen to run this module on.

[raymondbutcher]

If it doesn't break anything then it seems like a good idea. I have never tried the platform option and don't know how it works. If there is no manylinux version of a package, does pip get the regular version instead (as though no platform was specified) or does it error because it couldn't find a version for the specified platform?