Skip to content

How to use easily a virtual Python environment with Docker

Notifications You must be signed in to change notification settings

Tigrou59/Python-Docker

Repository files navigation

How to use easily a virtual Python environment with Docker

Make a quickly Python's environment with Docker for Developping and Testing under Linux

Advantage :

To create a Python virtual environment, several recommended tools exist like Pew, Venv and Pipenv...
Take a look: https://towardsdatascience.com/python-virtual-environments-made-easy-fe0c603fe601

But you will have to use binaries to install and configure them. If you want to install and use with more agility as many virtual environments and different versions of Python then Docker should be a serious alternative.

You don't need to use binaries for install your new virtual environment Python, any images and versions for Python are available under GitHub.

Create or delete a new virtual environment with Docker is really very quickly to do...

https://hub.docker.com/_/python/

https://github.com/docker-library/python

Install Docker CE on Linux "Ubuntu"

https://docs.docker.com/install/linux/docker-ce/ubuntu/

sudo apt-get update && apt-get install docker-ce docker-ce-cli containerd.io

Install Compose on Linux systems

Run this command to download the latest version of Docker Compose:

sudo curl -L "https://github.com/docker/compose/releases/download/1.23.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

Apply executable permissions to the binary:

sudo chmod +x /usr/local/bin/docker-compose

Verify version for Docker & Docker Compose

docker --version

Docker version 18.06.1-ce, build e68fc7a

docker-compose --version

docker-compose version 1.23.2, build 1110ad01

Create a local Dockerfile from the repo GitHub :

curl -LO https://raw.githubusercontent.com/docker-library/python/3189e185470f8abd8957c78973cda6b2413ca0fe/3.7/stretch/slim/Dockerfile

Build an image named Python slim 3.7 from a Dockerfile The build's context is set where is the file Dockerfile created above

docker image build -t slim/python:3.7 .

A little screen showing the end of the image's build...

+ pip --version
pip 19.0.2 from /usr/local/lib/python3.7/site-packages/pip (python 3.7)
+ find /usr/local -depth ( ( -type d -a ( -name test -o -name tests ) ) -o ( -type f -a ( -name *.pyc -o -name *.pyo ) ) ) -exec rm -rf {} +
+ rm -f get-pip.py
Removing intermediate container ded4d017c96c
 ---> 75d9999bdbd0
Step 11/11 : CMD ["python3"]
 ---> Running in 4f24a72e183a
Removing intermediate container 4f24a72e183a
 ---> 717c4c493d2f
Successfully built 717c4c493d2f
Successfully tagged slim/python:3.7

List the Docker images created with the build command

docker image ls

REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
slim/python         3.7                 717c4c493d2f        2 minutes ago       143MB
debian              stretch-slim        9a4a82cec2d2        7 days ago          55.3MB

Now we can run a container named "my-python" on the image "slim-python:3.7"

docker container run -it --rm --name my-python slim/python:3.7

For to keep datas persistent, we will use a volume Docker mounted on the host and a specific workdir in the container

docker container run -it --rm --name my-python -v "$PWD":/usr/src/myapp -w /usr/src/myapp slim/python:3.7

Testing the good functionnalities in our Python container

Python 3.7.2 (default, Feb 13 2019, 10:47:41) [GCC 6.3.0 20170516] on linux Type "help", "copyright", "credits" or "license" for more information.

>>> a, b, c = 1, 1, 1    # fibonacci : a et b servent au calcul des termes successifs, c est un simple compteur
>>> while c<15:
...     print(b, end=' ')
...     a, b, c = b, a+b, c+1
...
1 2 3 5 8 13 21 34 55 89 144 233 377 610

The best way is to use Docker Compose for create a service Python 3.7

mkdir compose

cd compose

vi docker-compose.yml

version: '3.7'
services:
  slim-python:
    image: slim/python:3.7
    container_name: python-37
    restart: unless-stopped
    working_dir: /usr/src/myapp
    stdin_open: true
    tty: true
    command: python3
    volumes:
      - PythonVol:/usr/src/myapp
volumes:
  PythonVol:

We have added some option related with the interactive mode and a named volume for hold the persistent datas, we run the service directly, not in background >> (docker-compose up -d), but simply with the run option on the service

docker-compose run slim-python

Creating network "compose_default" with the default driver
Creating volume "compose_PythonVol" with default driver
Python 3.7.2 (default, Feb 13 2019, 10:47:41)
[GCC 6.3.0 20170516] on linux
Type "help", "copyright", "credits" or "license" for more information.

>>>
CTRL+d

Verifiing the compose's service

docker-compose ps

Name   Command   State   Ports
-----------------------------------
python-37   python3   Up    

With a named volume, we can easily use a Docker command for inspect the mount point or any other action on this volume

docker volume ls

DRIVER              VOLUME NAME
local               compose_PythonVol

docker volume inspect -f '{{.Mountpoint}}' compose_PythonVol

  /var/lib/docker/volumes/compose_PythonVol/_data

Testing the persistent datas with a file "fibonacci.py"

cp fibonacci.py /var/lib/docker/volumes/compose_PythonVol/_data/

Run the service Docker "slim-python" then execute the file "fibonacci.py" with the exec command under the prompt Python >>>

docker-compose run slim-python

>>> exec(open("fibonacci.py").read())

1 2 3 5 8 13 21 34 55 89 144 233 377 610

For keep the persistent datas under the Docker volume, keep in mind that we must down the service with the command below (without the option -v, else this would delete the named volume)

docker-compose down

Removing compose_slim-python_run_22082e300e08 ... done
Removing network compose_default

Now we can verify that the datas "in our case, the file fibonacci.py" is always present under the volume Docker

I list only the directory inspected above with the command "docker volume inspect"

ll $(docker volume inspect -f {{'.Mountpoint'}} compose_PythonVol)

-rwxr-xr-x 1 root root  158 févr. 17 22:03 fibonacci.py*

Datas are always present under the volume Docker even the service is deleted

docker-compose ps

Name   Command   State   Ports
------------------------------

docker container ls -a

CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES

For completing our use case with "Docker Compose for create a service Python 3.7"

We can restart the service Docker with the command :

docker-compose run slim-python

Creating network "compose_default" with the default driver
Python 3.7.2 (default, Feb 13 2019, 10:47:41)
[GCC 6.3.0 20170516] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>

we can observate that the command don't re-create the volume because it's already exist and store the persistent datas

Releases

No releases published

Packages

No packages published