Seamlessly manage Python virtual environment with a Makefile

Makefile.venv takes care of creating, updating and invoking Python virtual environment that you can use in your Makefiles. It will allow you to reduce venv related routines to almost zero!

Installation

Recommended method

Copy Makefile.venv to your project directory and add include statement to the bottom of your Makefile:

include Makefile.venv

Alternative method

Alternatively, you can add installation actions as the Makefile rule:

Note the checksum step! Do not skip it, it would be as bad as piping curl to shell!

include Makefile.venv
Makefile.venv:
	curl \
		-o Makefile.fetched \
		-L "https://github.com/sio/Makefile.venv/raw/v2020.08.14/Makefile.venv"
	echo "5afbcf51a82f629cd65ff23185acde90ebe4dec889ef80bbdc12562fbd0b2611 *Makefile.fetched" \
		| sha256sum --check - \
		&& mv Makefile.fetched Makefile.venv

Notes:

• curl and/or sha256sum may not be available by default depending on what OS and configuration is used
• To install sha256sum on macOS use brew install coreutils
• You can use Perl's shasum -a 256 instead of sha256sum, as described here.

Usage

When writing your Makefile use $(VENV)/python to refer to the Python interpreter within virtual environment and $(VENV)/executablename for any other executable in venv.

Demo screencast

Targets

Makefile.venv provides the following targets. Some are meant to be executed directly via make $target, some are meant to be dependencies for other targets written by you.

venv

Use this as a dependency for any target that requires virtual environment to be created and configured.

venv is a .PHONY target and rules that depend on it will be executed every time make is run. This behavior is sensible as default because most Python projects use Makefiles for running development chores, not for artifact building. In cases where that is not desirable use order-only prerequisite syntax:

artifacts.tar.gz: | venv
	...

python, ipython

Execute these targets to launch interactive Python shell within virtual environment. Ipython is not installed by default when creating the virtual environment but will be installed automatically when called for the first time.

shell, bash, zsh

Execute these targets to launch interactive command line shell. shell target launches the default shell Makefile executes its rules in (usually /bin/sh). bash and zsh can be used to refer to the specific desired shell (if it's installed).

show-venv

Execute this target to show versions of Python and pip, and the path to the virtual environment. Use this for debugging purposes.

clean-venv

Execute this target to remove virtual environment. You can add this as a dependency to the clean target in your main Makefile.

$(VENV)/executablename

Use this target as a dependency for tasks that need executablename to be installed if executablename is not listed as project's dependency neither in requirements.txt nor in setup.py. Only packages with names matching the name of the corresponding executable are supported.

This can be a lightweight mechanism for development dependencies tracking. E.g. for one-off tools that are not required in every developer's environment, therefore are not included in formal dependency lists.

Note: Rules using such dependency MUST be defined below include directive to make use of correct $(VENV) value.

Example (see ipython target for another example):

codestyle: $(VENV)/pyflakes  # `venv` dependency is assumed and may be omitted
	$(VENV)/pyflakes .

Variables

Makefile.venv can be configured via following variables:

PY

Command name for system Python interpreter. It is used only initially to create the virtual environment. Default: python3

REQUIREMENTS_TXT

Space separated list of paths to requirements.txt files. Paths are resolved relative to current working directory. Default: requirements.txt

WORKDIR

Parent directory for the virtual environment. Default: current working directory

VENVDIR

Python virtual environment directory. Default: $(WORKDIR)/.venv

PIP_*

Variables named starting with PIP_ are not processed by Makefile.venv in any way and are passed to underlying pip calls as is. See pip documentation for more information.

Use these variables to customize pip invocation, for example to provide custom package index url:

PIP_EXTRA_INDEX_URL="https://your.index/url"

Samples

Makefile:

.PHONY: test
test: venv
	$(VENV)/python -m unittest

include Makefile.venv

Larger sample from a real project can be seen here. Also see an introductory blog post from project author.

Command line:

$ make test

...Skipped: creating and updating virtual environment...

...
----------------------------------------------------------------------
Ran 3 tests in 0.000s

OK

$ make show-venv
Python 3.5.4 (v3.5.4:3f56838, Aug  8 2017, 02:07:06) [MSC v.1900 32 bit (Intel)]
pip 19.2.3 from c:\users\99e7~1\appdata\local\temp\.venv\lib\site-packages\pip (python 3.5)
venv: C:\Users\99E7~1\AppData\Local\Temp\.venv

$ make python
C:/Users/99E7~1/AppData/Local/Temp/.venv/Scripts/python
Python 3.5.4 (v3.5.4:3f56838, Aug  8 2017, 02:07:06) [MSC v.1900 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> _

Compatibility

Makefile.venv was written for GNU Make and may not work with other make implementations. Please be aware that GNU Make can not correctly handle whitespace characters in file paths. Such filepaths therefore are considered unsupported by Makefile.venv

Makefile.venv is being continuously tested on Linux, Windows and macOS. Any inconsistency encountered when running on Windows should be considered a bug and should be reported via issues.

Support and contributing

If you need help with using this Makefile or including it into your project, please create an issue. Issues are also the primary venue for reporting bugs and posting feature requests. General discussion related to this project is also acceptable and very welcome!

In case you wish to contribute code or documentation, feel free to open a pull request. That would certainly make my day!

I'm open to dialog and I promise to behave responsibly and treat all contributors with respect. Please try to do the same, and treat others the way you want to be treated.

If for some reason you'd rather not use the issue tracker, contacting me via email is OK too. Please use a descriptive subject line to enhance visibility of your message. Also please keep in mind that public discussion channels are preferable because that way many other people may benefit from reading past conversations. My email is visible under the GitHub profile and in the commit log.

License and copyright

Copyright 2019-2020 Vitaly Potyarkin

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.