Background

I would like to have a working python environment with python 2.7.12 and a series of packages. It shall be efficient, and yet easy to setup. The anaconda distribution almost satisfies my needs, except that it’s unreasonably slow to load, due to its bundle of system libs. There are also python version managers such as pyenv and pythonz. The drawback of pyenv is the shims, which are scripts to launch binaries such as python2 and pip. shims make powerline client slow, which is undesirable. As to pythonz, it only handles multiple versions of python, no other infrastructure is provided.

After some experimentation, I found that just compile python from source and install it into customized location works just fine. There are some caveats, so I record it here.

Compile Python

Compile python is easy, just be sure to install bundled pip.

tar -zxvf Python-2.7.12.tgz
cd Python-2.7.12
./configure --prefix=$LOCATION --with-ensurepip=install
make
make install

After that, you can find python under $LOCATION. $LOCATION/bin/python -m site will show site-packages under $LOCATION/lib/python2.7/site-packages.

Install Packages using Pip

We would expect pip install XXX to install packages into site-packages. But this does not work in practice. Even with bundled pip, it often installs packages into system’s site-packages. To install to the correct location, we have to use python -m pip.

export PATH=$LOCATION/bin:$PATH
python -m pip install XXX

Move Installation Around

I have not yet tested it, but I expect it would be just copy $LOCATION to a new location and set PYTHONPATH and PATH to correct values in new location. I will try it.