Memory error while using pip install Airflow

This error is coming up because, it seems, pip‘s caching mechanism is trying to read the entire file into memory before caching it… which poses a problem in a limited-memory environent, as matplotlib is ~50mb.

A simpler solution, until pip is patched to use a constant-space caching algorithm, is to run pip with --no-cache-dir to avoid the cache:

$ pip --no-cache-dir install airflow