pip-downloader

pip-downloader helps in allowing offline installations of python packages.

pip download already exists, which does something similar:

• Pro: Handles dependency resolution in the same way pip install does - so no confusion
• Pro: It is useful to download all the source packages with the --no-binary :all: argument.
• Con: It downloads only 1 file per package (i.e. only source or only one of the wheel files)

• Con: For downloads of a different system (not the system you're running it from) it expects

  the package and all it's dependencies to have similar wheels (eg: If cp36m-manylinux is the wheel for one library, all it's dependencies should also have that wheel)

pip-downloader aims to solve the same issue but in a slightly different way:

• It uses the same dependency resolution pip download uses but after resolving the dependencies
• It downloads all the files (source and all wheels) available for that version of the package

This gives an experience that is more consistent with the online installation with pip as it has all the files (all wheels and sources) for installation.

Installation

It is recommended to use the latest version of pip (currently - 19.1) when using pip-downloader.

pip install pip-downloader

Usage

The command line utility pip-downloader should be available.

# To get help about pip-downloader
pip-downloader --help

# To fetch the list of packages and their versions that downloader will download (dry-run)
pip-downloader list flask 

# To download the list of packages and their versions to the provided destination
pip-downloader download flask --dest /tmp/pypi

Known Limitations

• Dependencies mentioned in setup_requires are not downloaded as pip's dependency resolution mechanism does not consider them at the moment. Common setup-time requirements are: setuptools_scm, vcversioner, numpy, etc.
• Build dependencies mentioned in pyproject.toml are not downlaoded as pip's dependency manages install/run-time dependencies at the moment. (These are needed only if source installation is chosen when installing a package.)
• When solving for packages with sys_platform environment markers, the package resolution will happen based on the machine you're running pip-downloader from. Need to investigate on how to resolve this issue.