A set of command line tools to help you keep your pip-based packages fresh, even when you've pinned them. You do pin them, right?

As part of a Python project's environment tooling (similar to pip), it's recommended to install pip-tools in each project's virtual environment:

$ source /path/to/venv/bin/activate
(venv)$ pip install pip-tools

Note: all of the remaining example commands assume you've activated your project's virtual environment.

The pip-compile command lets you compile a requirements.txt file from your dependencies, specified in either setup.py or requirements.in.

Run it with pip-compile or python -m piptools compile. If you use multiple Python versions, you can run pip-compile as py -X.Y -m piptools compile on Windows and pythonX.Y -m piptools compile on other systems.

Note: ensure you don't have requirements.txt if you compile setup.py or requirements.in from scratch, otherwise, it might interfere.

Suppose you have a Flask project, and want to pin it for production. If you have a setup.py with install_requires=['Flask'], then run pip-compile without any arguments:

$ pip-compile
#
# This file is autogenerated by pip-compile
# To update, run:
#
#    pip-compile --output-file requirements.txt setup.py
#
click==6.7                # via flask
flask==0.12.2
itsdangerous==0.24        # via flask
jinja2==2.9.6             # via flask
markupsafe==1.0           # via jinja2
werkzeug==0.12.2          # via flask

pip-compile will produce your requirements.txt, with all the Flask dependencies (and all underlying dependencies) pinned. You should put requirements.txt under version control.

If you don't use setup.py (it's easy to write one), you can create a requirements.in file to declare the Flask dependency:

# requirements.in
Flask

Now, run pip-compile requirements.in:

$ pip-compile requirements.in
#
# This file is autogenerated by pip-compile
# To update, run:
#
#    pip-compile --output-file requirements.txt requirements.in
#
click==6.7                # via flask
flask==0.12.2
itsdangerous==0.24        # via flask
jinja2==2.9.6             # via flask
markupsafe==1.0           # via jinja2
werkzeug==0.12.2          # via flask

And it will produce your requirements.txt, with all the Flask dependencies (and all underlying dependencies) pinned. You should put both requirements.in and requirements.txt under version control.

If you would like to use Hash-Checking Mode available in pip since version 8.0, pip-compile offers --generate-hashes flag:

$ pip-compile --generate-hashes requirements.in
#
# This file is autogenerated by pip-compile
# To update, run:
#
#    pip-compile --generate-hashes --output-file requirements.txt requirements.in
#
click==6.7 \
    --hash=sha256:29f99fc6125fbc931b758dc053b3114e55c77a6e4c6c3a2674a2dc986016381d \
    --hash=sha256:f15516df478d5a56180fbf80e68f206010e6d160fc39fa508b65e035fd75130b \
    # via flask
flask==0.12.2 \
    --hash=sha256:0749df235e3ff61ac108f69ac178c9770caeaccad2509cb762ce1f65570a8856 \
    --hash=sha256:49f44461237b69ecd901cc7ce66feea0319b9158743dd27a2899962ab214dac1
itsdangerous==0.24 \
    --hash=sha256:cbb3fcf8d3e33df861709ecaf89d9e6629cff0a217bc2848f1b41cd30d360519 \
    # via flask
jinja2==2.9.6 \
    --hash=sha256:2231bace0dfd8d2bf1e5d7e41239c06c9e0ded46e70cc1094a0aa64b0afeb054 \
    --hash=sha256:ddaa01a212cd6d641401cb01b605f4a4d9f37bfc93043d7f760ec70fb99ff9ff \
    # via flask
markupsafe==1.0 \
    --hash=sha256:a6be69091dac236ea9c6bc7d012beab42010fa914c459791d627dad4910eb665 \
    # via jinja2
werkzeug==0.12.2 \
    --hash=sha256:903a7b87b74635244548b30d30db4c8947fe64c5198f58899ddcd3a13c23bb26 \
    --hash=sha256:e8549c143af3ce6559699a01e26fa4174f4c591dbee0a499f3cd4c3781cdec3d \
    # via flask

To update all packages, periodically re-run pip-compile --upgrade.

To update a specific package to the latest or a specific version use the --upgrade-package or -P flag:

# only update the flask package
$ pip-compile --upgrade-package flask

# update both the flask and requests packages
$ pip-compile --upgrade-package flask --upgrade-package requests

# update the flask package to the latest, and requests to v2.0.0
$ pip-compile --upgrade-package flask --upgrade-package requests==2.0.0

You can combine --upgrade and --upgrade-package in one command, to provide constraints on the allowed upgrades. For example to upgrade all packages whilst constraining requests to the latest version less than 3.0:

$ pip-compile --upgrade --upgrade-package 'requests<3.0'

To output the pinned requirements in a filename other than requirements.txt, use --output-file. This might be useful for compiling multiple files, for example with different constraints on flask to test a library with both versions using tox:

$ pip-compile --upgrade-package 'flask<1.0' --output-file requirements-flask0x.txt
$ pip-compile --upgrade-package 'flask<2.0' --output-file requirements-flask1x.txt

Or to output to standard output, use --output-file=-:

$ pip-compile --output-file=- > requirements.txt
$ pip-compile - --output-file=- < requirements.in > requirements.txt

You might be wrapping the pip-compile command in another script. To avoid confusing consumers of your custom script you can override the update command generated at the top of requirements files by setting the CUSTOM_COMPILE_COMMAND environment variable.

$ CUSTOM_COMPILE_COMMAND="./pipcompilewrapper" pip-compile requirements.in
#
# This file is autogenerated by pip-compile
# To update, run:
#
#    ./pipcompilewrapper
#
flask==0.10.1
itsdangerous==0.24        # via flask
jinja2==2.7.3             # via flask
markupsafe==0.23          # via jinja2
werkzeug==0.10.4          # via flask

If you have different environments that you need to install different but compatible packages for, then you can create layered requirements files and use one layer to constrain the other.

For example, if you have a Django project where you want the newest 2.1 release in production and when developing you want to use the Django debug toolbar, then you can create two *.in files, one for each layer:

# requirements.in
django<2.2

At the top of the development requirements dev-requirements.in you use -c requirements.txt to constrain the dev requirements to packages already selected for production in requirements.txt.

# dev-requirements.in
-c requirements.txt
django-debug-toolbar

First, compile requirements.txt as usual:

$ pip-compile
#
# This file is autogenerated by pip-compile
# To update, run:
#
#    pip-compile
#
django==2.1.12
pytz==2019.2              # via django

Now compile the dev requirements and the requirements.txt file is used as a constraint:

$ pip-compile dev-requirements.in
#
# This file is autogenerated by pip-compile
# To update, run:
#
#    pip-compile dev-requirements.in
#
django-debug-toolbar==2.0
django==2.1.12            # via django-debug-toolbar
sqlparse==0.3.0           # via django-debug-toolbar

As you can see above, even though a 2.2 release of Django is available, the dev requirements only include a 2.1 version of Django because they were constrained. Now both compiled requirements files can be installed safely in the dev environment.

Now that you have a requirements.txt, you can use pip-sync to update your virtual environment to reflect exactly what's in there. This will install/upgrade/uninstall everything necessary to match the requirements.txt contents.

Run it with pip-sync or python -m piptools sync. If you use multiple Python versions, you can also run py -X.Y -m piptools sync on Windows and pythonX.Y -m piptools sync on other systems.

Be careful: pip-sync is meant to be used only with a requirements.txt generated by pip-compile.

$ pip-sync
Uninstalling flake8-2.4.1:
  Successfully uninstalled flake8-2.4.1
Collecting click==4.1
  Downloading click-4.1-py2.py3-none-any.whl (62kB)
    100% |................................| 65kB 1.8MB/s
  Found existing installation: click 4.0
    Uninstalling click-4.0:
      Successfully uninstalled click-4.0
Successfully installed click-4.1

To sync multiple *.txt dependency lists, just pass them in via command line arguments, e.g.

$ pip-sync dev-requirements.txt requirements.txt

Passing in empty arguments would cause it to default to requirements.txt.

If you use multiple Python versions, you can run pip-sync as py -X.Y -m piptools sync ... on Windows and pythonX.Y -m piptools sync ... on other systems.

Note: pip-sync will not upgrade or uninstall packaging tools like setuptools, pip, or pip-tools itself. Use pip install --upgrade to upgrade those packages.

• pipdeptree to print the dependency tree of the installed packages.
• requirements.in/requirements.txt syntax highlighting:
  • requirements.txt.vim for Vim.
  • Python extension for VS Code for VS Code.