How to create Python work environments

In a previous post, I explained Why Python is the best development language.

As a python programmer, you may need to use various packages to deliver your solutions. These packages might not be all compatible with each other. This is a problem if you were to install all packages in the same environment for all your projects. It would not make sense having to manage multiple Linux virtual machines.

pipenv was created to provide developers with an easy method to set up working environments for each project. pipenv is based on virtualenv.

Install pipenv

pipenv is installed using the pip command:

$ sudo pip install pipenv

Create Work Environment

The following example creates a work environment named ‘project’ using Python 2.7

$ mkdir project
$ cd project
$ pipenv --two

To activate run

$ pipenv shell

Your command prompt shall be prefixed with your work environment name, mine looks like this:

(project)steve@Steven-Server:~/project$

To exit a work environment.

$ exit

Remove Work Environment

To remove a project’s virtualenv and files (when not in shell):

$ pipenv --rm
$ rm Pipf*

Sample 1

create > list project packages > remove > delete files

steve@Steven-Server:~$ mkdir project
steve@Steven-Server:~$ cd project
steve@Steven-Server:~/project$ pipenv --two
steve@Steven-Server:~/project$ pipenv shell
(project)steve@Steven-Server:~/project$ pip list
Launching subshell in virtual environment…
 . /home/steve/.local/share/virtualenvs/project-9jwDEFA1/bin/activate
steve@Steven-Server:~/project$  . /home/steve/.local/share/virtualenvs/project-9jwDEFA1/bin/activate
(project)steve@Steven-Server:~/project$ pip list
Package    Version
---------- -------
pip        18.1
setuptools 40.4.3
wheel      0.32.1
(project)steve@Steven-Server:~/project$ exit
steve@Steven-Server:~/project$ pipenv --rm
steve@Steven-Server:~/project$ rm Pipf*

Sample 2

create > install host packages > list project packages > remove > delete files

steve@Steven-Server:~$ mkdir project
steve@Steven-Server:~$ cd project
steve@Steven-Server:~/project$ pipenv --two
steve@Steven-Server:~/project$ pipenv install --dev
steve@Steven-Server:~/project$ pipenv shell
(project)steve@Steven-Server:~/project$ pip list
Launching subshell in virtual environment…
 . /home/steve/.local/share/virtualenvs/project-9jwDEFA1/bin/activate
steve@Steven-Server:~/project$  . /home/steve/.local/share/virtualenvs/project-9jwDEFA1/bin/activate
(project)steve@Steven-Server:~/project$ pip list
Package    Version
---------- -------
asn1crypto        0.24.0
beautifulsoup4    4.6.3
certifi           2018.8.24
...
Werkzeug          0.14.1
wheel             0.30.0
(project)steve@Steven-Server:~/project$ exit
steve@Steven-Server:~/project$ pipenv --rm
steve@Steven-Server:~/project$ rm Pipf*

Under the hood

You will notice that two files are created Pipfile and Pipfile.lock

The Pipfile will content all the packages for the work environment

[[source]]
url = "https://pypi.org/simple"
verify_ssl = true
name = "pypi"
[dev-packages]
[packages]
flask = "*"
requests = "*"
[requires]
python_version = "2.7"

The Pipefile.lock will provide all the dependent packages for those you installed.

...
"certifi": {
	"hashes": [
		"sha256:376690d6f16d32f9d1fe8932551d80b23e9d393a8578c5633a2ed39a64861638",
		"sha256:456048c7e371c089d0a77a5212fb37a2c2dce1e24146e3b7e0261736aaeaa22a"
	],
	"version": "==2018.8.24"
},
"chardet": {
	"hashes": [
		"sha256:84ab92ed1c4d4f16916e05906b6b75a6c0fb5db821cc65e70cbd64a3e2a5eaae",
		"sha256:fc323ffcaeaed0e0a02bf4d117757b98aed530d9ed4531e3e15460124c106691"
	],
	"version": "==3.0.4"
},
"click": {
	"hashes": [
		"sha256:2335065e6395b9e67ca716de5f7526736bfa6ceead690adf616d925bdc622b13",
		"sha256:5b94b49521f6456670fdb30cd82a4eca9412788a93fa6dd6df72c94d5a8ff2d7"
	],
	"version": "==7.0"
...

Usage Examples

# Create a new project using Python 3.7, specifically:
$ pipenv --python 3.7

# Remove project virtualenv (inferred from current directory):
$ pipenv --rm

# Install all dependencies for a project (including dev):
$ pipenv install --dev

# Create a lockfile containing pre-releases:
$ pipenv lock --pre

# Show a graph of your installed dependencies:
$ pipenv graph

# Check your installed dependencies for security vulnerabilities:
$ pipenv check

# Install a local setup.py into your virtual environment/Pipfile:
$ pipenv install -e .

# Use a lower-level pip command:
$ pipenv run pip freeze

Commands

check      Checks for security vulnerabilities and against PEP 508 markers
			provided in Pipfile.
clean      Uninstalls all packages not specified in Pipfile.lock.
graph      Displays currently-installed dependency graph information.
install    Installs provided packages and adds them to Pipfile, or (if no
			packages are given), installs all packages from Pipfile.
lock       Generates Pipfile.lock.
open       View a given module in your editor.
run        Spawns a command installed into the virtualenv.
shell      Spawns a shell within the virtualenv.
sync       Installs all packages specified in Pipfile.lock.
uninstall  Un-installs a provided package and removes it from Pipfile.

Where to go from here

Getting Started with Python
Essential Python Packages