Drake: installation instructions reference missing requirements.txt

[RussTedrake]

looks like we missed a file.

sudo pip install -U -r requirements.txt

is in http://drake002.csail.mit.edu/drake/sphinx/ubuntu.html (and perhaps other platforms) but that file seems to have not made it into the repo.

[jwnimmer-tri]

Without derailing this too much (yes, we should capture the currently-required steps)...

Doing a sudo pip install ... on Ubuntu is extremely gross. If I am reading it right, that will install python files directly unto /usr/lib, outside of the debian packaging system! Or is there some requirements.txt phrasing that puts the packages into $HOME instead (in which case, why use sudo)?

[liangfok]

I wouldn't worry too much about using pip since it's a standard packaging system for software written in Python. If putting things in /usr/lib is undesirable, we can use the --target <dir> flag:

sudo pip install -U --target $DRAKE_HOME/build/lib/python2.7/site-packages -r requirements.txt

[jwnimmer-tri]

Pip is great. My complaint is about the command that the setup instructions currently specify, which will screw up your Ubuntu in a nearly-unrecoverable way, AFAICT. In general, sudo for anything other than apt commands is a defect in installation instructions.

[rdeits]

I suppose whether it's "gross" or not is subject to opinion, but sudo pip install is entirely standard practice for installing python packages systemwide on ubuntu, since the python packages available from the standard apt repositories tend to be pretty out-of-date. And any package that was pip installed can also be pip uninstalled, so it's generally not unrecoverable.

[liangfok]

A valid concern that was raised numerous times in recent weeks is whether the inclusion of a particular dependency will result in problems when Drake is integrated within a larger system that has a different set of dependencies (or versions of the same dependencies). How can we maximize the probability that Drake's dependencies do not clash when integrated into a larger system? Requiring that certain dependencies be installed in a system-wide manner seems risky in terms of inviting dependency clashes.

Another concern with relying on system-wide dependencies managed by apt or pip is the fact that Drake will have less control over when they are upgraded or deprecated. For example, I faced this problem with yaml when switching from Ubuntu 12.04 (which uses version 0.3) to 14.04 (which uses version 0.5). Drake will need to "keep up" with these system-wide changes as they occur.

Not saying we shouldn't rely on system-wide dependencies. Just need to be conscious about the consequences of doing so.

[patmarion]

What packages are in requirements.txt? Was pip being used because the ubuntu provided versions were too old?

[jhoare]

It seems to me like the concerns about using pip could be alleviated by creating a virtualenv ( http://docs.python-guide.org/en/latest/dev/virtualenvs/ )

The downside of this, of course, is that the developer would need to activate the virtual environment first before doing drake activities. Drake doesn't provide a setup.bash or anything that sets up the user's environment does it?

[rdeits]

Virtualenv is definitely a good solution if we want to avoid polluting the global system. Drake does actually produce build/config/pods_setup_all.sh, which is populated by the pods_install_bash_setup Cmake macro. That might be a good place to activate a virtualenv.

[RussTedrake]

We have provided a setup.sh in previous projects (including the drc) but have resisted so far in drake.

[patmarion]

Ok, but before discussing virtualenv can someone post the python packages listed in requirements.txt? What python dependencies does drake have? I can only think of director and iris externals having python dependencies, and python gtk to run bot-procman.

[jamiesnape]

Per the installation instructions, sphinx and cpplint. Everything else is installed by package managers.

[jwnimmer-tri]

I'll suggest checking out cpplint from github as part of the superbuild, instead of firing off pip install during one-time setup. I believe it will be a more successful mechanism to keep everyone using the same version of the tool.

[patmarion]

can you use the python-sphinx package provided by ubuntu, or is the version too old to support drake's docs?

http://packages.ubuntu.com/trusty/python-sphinx

[jamiesnape]

Possibly, but all the other platforms will use pip, so depends if you like to be consistent.

[jamiesnape]

@jwnimmer-tri Sure. This will get people up and running for now.