This blog was originally posted on:
https://sm087.github.io/pipenv-quickstart.html
Pipenv is a packaging tool for Python that solves some common problems associated with the typical workflow using pip, virtualenv, and the good old requirements.txt.
Installation
pip3 install pipenv
Package installation using pipenv
pipenv install requests
If a pipenv is not setup for the application yet, running the above will create a virtual environment along with the installation of pipenv and also create Pipfile and Pipfile.lock under the application directory.
The below shows a sample pipfile (toml):
[[source]]
name = "pypi"
url = "https://pypi.org/simple"
verify_ssl = true
[dev-packages]
[packages]
requests = "*"
[requires]
python_version = "3.7"
you can install package you need, flask. For example you need version 0.12.1 and not the latest version, so go ahead and be specific by:
pipenv install flask==0.12.1
You can also install directly from a version control system by:
pipenv install -e git+https://github.com/requests/requests.git#egg=requests
Production Environment based package Install
Let’s say you have some unit tests for the application that you are building, and you want to use pytest for running them. You don’t need pytest in production so you can specify that this dependency is only for development with the --dev argument:
pipenv install pytest --dev
This package will be auto added by pipenv to the Pipfile under [dev-packages].
Activate your pipenv environment
Spawn a shell in a virtual environment to isolate the development of your app by running:
pipenv shell
Deactivate your pipenv environment
To deactivate the environment spawned by running the above command use exit. Avoid using deactivate as this does not completely (not a clean) exit from a pipenv environment.
(myenv)$ exit
exit
Running a script
You can run a script without activating the environment created.
pipenv run python scripts.py
You can also run a command in the virtual environment without launching a shell by:
pipenv run <insert command here>
Install from requirements.txt
You can install required packaged for an app from a legacy virtual environment requirements.txt
pipenv install -r pathto/requirements.txt
Uninstall a Package
Now, let’s say you no longer need a package. You can uninstall it:
pipenv uninstall requests
If you want to wipe off all the packages from the environment:
pipenv uninstall --all
Pip Freeze in pipenv
This is the equivalent to pip freeze, gives you the list of packages installed under that environment.
pipenv lock -r
PipEnv Path(s)
To find out where your virtual environment is located:
pipenv --venv
To find out where your project home is
pipenv --where
Package vulnerabilities
Check for security vulnerabilities in your environment:
pipenv check
Environment Variables and PipEnv
Pipenv supports the automatic loading of environmental variables when a .env file exists in the project directory. That way, when you pipenv shell to open the virtual environment, it loads your environmental variables from the file. The .env file just contains key-value pairs:
SECRET_KEY=somerandomekey
14:03:47~/PycharmProjects/cloudMigrationDVApp$ pipenv run python
Loading .env environment variables…
Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 16:52:21)
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> os.environ['SECRET_KEY']
'somerandomekey'
>>>
Dependency mapping with PipEnv (with pipenv graph command)
Pipenv can show a dependency graph to understand your top-level dependencies and their sub-dependencies:
pipenv graph
$ pipenv graph
openpyxl==2.6.2
- et-xmlfile [required: Any, installed: 1.0.1]
- jdcal [required: Any, installed: 1.4.1]
requests==2.22.0
- certifi [required: >=2017.4.17, installed: 2019.3.9]
- chardet [required: >=3.0.2,<3.1.0, installed: 3.0.4]
- idna [required: >=2.5,<2.9, installed: 2.8]
- urllib3 [required: >=1.21.1,<1.26,!=1.25.1,!=1.25.0, installed: 1.25.3]
Switch to a different python version
Given a situation if your app python version needs to be changed from one version to another pipenv pipfile can be edited to change the python version under:
[requires]
python_version = "3.6" ## changed from 3.7 to 3.6
And then by running the below will reinstall the virtual environment with the version specified.
pipenv --python 3.6
To remove pipenv completely
You can remove the pipenv environment completely by running
pipenv --rm
This will still not delete the Pipfile and the Pipfile.lock, this would need to be manually removed (If not needed).
To install the pipenv with the pipfile`s in place, run:
pipenv install
Changing version of a package installed
In order to update a pip package change the version under the pip file.
[packages]
openpyxl = "*"
requests = "==2.22.0" # Changed from 2.21 to 2.22
and then run:
pipenv install
Should result in the required version installed:
$ pipenv lock -r | grep requests
requests==2.22.0
Production Ready
Once your application is ready with the required packages in development, You need to lock your environment to ensure you have the same (version) packages in production:
pipenv lock
This will create/update your Pipfile.lock, which you’ll never need to (and are never meant to) edit manually.
Once you get your code and Pipfile.lock in your production environment, you should install the last successful environment recorded by:
pipenv install --ignore-pipfile
This tells Pipenv to ignore the Pipfile for installation and use what’s in the Pipfile.lock.
Dev Environment
To setup packages and environment for dev environment:
pipenv install --dev
From legacy virtualenv to pipenv
If you have a dev-requirements.txt or something similar, you can add those to the Pipfile as well by:
pipenv install -r dev-requirements.txt --dev
Additionally, you can go the other way and generate requirements files from a Pipfile.
pipenv lock -r > requirements.txt
pipenv lock -r -d > dev-requirements.txt
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