In this guide you will learn how to:
- Create a
Dockerfile
file describing a simple Python container. - Build, run, and verify the functionality of a Django, Flask, or General Python app.
- Debug the app running in a container.
Prerequisites
FROM python:3.9.1 RUN apt-get update RUN apt-get -y install tesseract-ocr RUN apt-get install tesseract-ocr-ben ADD. /tesseract-python WORKDIR /tesseract-python RUN pip install -r requirements.txt. The From command is used to define the parent image. Here I’m using the pre-built official image of Python from Docker Hub. This command will download the python:rc image from Docker Hub, start a container, and run python inside that container. The -it options are necessary for running the container interactively. The rc tag is shorthand for release candidate and points to the latest development version of Python. Note: Removing a Container is FINAL. Delete a Single Container. Run docker ps -a and retrieve the container ID (an alphanumeric string, something like a39c259df462). Run docker rm a39c259df462 to remove just that container. Delete All Your Containers. To delete all your containers, run: $.
- Docker Desktop and the VS Code Docker extension must be installed as described in the overview.
- For Python development, complete all Getting started with Python steps
- A runnable Python application
Create a Python project
If you don't have a Python project already, follow these commands sequentially from the terminal:
If you want to containerize a complete Django or Flask web app, you can use one of the following samples:
- python-sample-vscode-django-tutorial, which is the result of following the Django Tutorial
- python-sample-vscode-flask-tutorial, which is the result of following the Flask TutorialTo Install macOS Mojave on VMware on Windows 10 using a pre-made ISO filled with only macOS Mojave setup then go through the step by step guide down below and do exactly as the guide is shown. Newer versions of macOS are out, So check the guides below to install them. Jun 22, 2018 How to use the macOS Mojave USB installer. 1) Shut down your Mac with the USB drive inserted. 2) Start up the computer whilst holding the Option (⌥) key. 3) Select the drive called “Install macOS Mojave Beta” from the Startup Manager using the keyboard arrow keys. The computer will now boot from the selected drive. Install mojave link mac.
After verifying your app runs properly, you can now Dockerize your application.
Add Docker files to the project
![Install python docker containers Install python docker containers](/uploads/1/3/7/3/137300292/999043610.png)
- Open the project folder in VS Code.
- Open the Command Palette (⇧⌘P (Windows, Linux Ctrl+Shift+P)) and use the Docker: Add Docker Files to Workspace.. command:
- When the prompt appears, select Python: Django, Python: Flask, or Python: General as the app type. For this tutorial, we will select Python: Django.
- Select either Yes or No when prompted to include Docker Compose files. If you select Yes, you will need to verify the path to your
wsgi.py
file in theDockerfile
to run the Compose Up command successfully. Compose is typically used when running multiple containers at once. - Enter the relative path to the app's entry point. This excludes the workspace folder you start from. According to official Django documentation, this path is commonly
manage.py
(root folder) orsubfolder_name/manage.py
. According to official Flask documentation, this is the path to where you create your Flask instance.Tip: You may also enter the path to a folder name as long as this folder includes a__main__.py
file. - If Python: Django or Python: Flask was selected, specify app port for local development. Django defaults to port 8000, while Flask defaults to port 5000; however, any unused port will work. We recommend selecting port 1024 or above to mitigate security concerns from running as a root user.
- With all of this information, the Docker extension creates the following files:Thank you for coming back to me. My Mac is 10.8.6 from memory. I had gone into Debenhams website and got message saying unsafe and I may need to upgrade browser, giving me link to El Capitan. Tried to install, told me it couldn’t and I’ve now got XS 0 installer on screen which won’t quit despite me trying as per above. Mac pro 1.1 el capitan install. Search for ( 'How to Install Windows 10 onto Mac OSX El Capitan using Bootcamp ' ). Macbook Pro 13 Upgrade Parts list: Apple MacBook Pro MD101LL/A 13.3-Inch Laptop Apple 13-inch MacBook Pro (Intel Dual Core i5 2.5GHz, 4GB RAM, 500GB HDD, HD Graphics 4000, OS X Lion) Samsung Evo 850 500gb. El Capitan is Apple’s marketing name for OS X version 10.11, the latest update to your Mac’s system software. If your Mac is running Yosemite (10.10), Mavericks (10.9), or Mountain Lion (10.8.
- A
Dockerfile
. To learn more about IntelliSense in this file, refer to the overview. - A
.dockerignore
file to reduce the image size by excluding files and folders that aren't needed such as.git
,.vscode
, and__pycache__
. - Imovie for mac old version. If Docker Compose was selected, a
docker-compose.yml
anddocker-compose.debug.yml
file. - If one does not already exist, a
requirements.txt
file for capturing all app dependencies.
Important note: To use our setup, the Python framework (Django/Flask) and Gunicorn must be included in therequirements.txt
file. If the virtual environment/host machine already has these prerequisites installed and is supposed to be identical to the container environment, ensure app dependencies are ported over by runningpip freeze > requirements.txt
in the terminal. This will overwrite your currentrequirements.txt
file.
Add an environment variable to the image
The Docker Extension helps you author Dockerfiles by using IntelliSense to provide auto-completions and contextual help. To see this feature in action:
![Container Container](/uploads/1/3/7/3/137300292/601782496.png)
- Open the
Dockerfile
. - Underneath the
EXPOSE
statement, type ⌃Space (Windows, Linux Ctrl+Space) to trigger IntelliSense and scroll toENV
. - Press Tab or Enter to complete the statement, then set the
key
to VAR1 and thevalue
to 10.
Gunicorn modifications for Django/Flask apps
To give Python Web Developers a great starting point, we chose to use Gunicorn as the default web server. Since it is referenced in the default Dockerfile, it is included as a dependency in the
requirements.txt
file.Note: To use Gunicorn as your web server, it must be included in the
requirements.txt
file as an app dependency. It does not need to be installed in your virtual environment/host machine. The Gunicorn entry point is overridden locally if your app is run with Python: Django or Python: Flask.Django apps
To use Gunicorn, it must bind to an application callable (what the application server uses to communicate with your code) as an entry point. This callable is declared in the
wsgi.py
file of a Django application. To accomplish this binding, the final line in the Dockerfile says:If your project does not follow Django's default project structure (that is, a workspace folder and a wsgi.py file within a subfolder named the same as the workspace) you must overwrite the Gunicorn entry point in the Dockerfile to locate the correct
wsgi.py
file.Tip: If your
wsgi.py
file is in the root folder, the final argument in the command above will be 'wsgi'
. Within subfolders, the argument would be 'subfolder1_name.subfolder2_name.wsgi'
.Flask apps
To use Gunicorn, it must bind to an application callable (what the application server uses to communicate with your code) as an entry point. This callable corresponds with the file location and variable name of your created Flask instance. According to official Flask Documentation, users generally create a Flask instance in the main module or in the
__init__.py
file of their package in this manner:To accomplish this binding, the final line in the Dockerfile says:
During the Docker: Add Docker Files to Workspace.. command, you configure the path to the Flask instance, however, the Docker extension assumes your Flask instance variable is named
app
. If this is not the case, you must change the variable name in the Dockerfile.Tip: If your main module was in the root folder as a file named
main.py
and had a Flask instance variable was named myapp
, the final argument in the command above will be 'main:myapp'
. Within subfolders, the argument would be 'subfolder1_name.subfolder2_name.main:myapp'
.Build, run, and debug the container
The Docker: Add Docker Files to Workspace.. command automatically creates a Docker launch configuration to build and run your container in debug mode. To debug your Python app container:
- Navigate to the
manage.py
file and set a breakpoint on this line:Note: If you have created an app project as shown in the Create a Django app section of the Django tutorial, you can also set a breakpoint inviews.py
or wherever you choose. - Navigate to Run and Debug and select Docker: Python - Django.
- Start debugging using the F5 key.
- The Docker image builds.
- The Docker container runs.
- The python debugger stops at the breakpoint in
manage.py
.
- Step over this line once.
- Navigate to the Debug Console and type
os.environ['DJANGO_SETTINGS_MODULE']
- Once you view the output, press continue.
The Docker extension will launch your browser to a randomly mapped port:
Tip: To modify your Docker build settings, such as changing the image tag, navigate to
.vscode -> tasks.json
under the dockerBuild
attribute in the docker-build
task. Use IntelliSense within the file (⌃Space (Windows, Linux Ctrl+Space)) to display all other valid directives.Use the Docker Explorer
The Docker Explorer provides an interactive experience to examine and manage Docker assets such as containers, images, and so on. To see an example:
Install Python Module In Docker Container
- Navigate to the Docker Explorer.
- In the Containers tab, right-click on your container and choose View Logs.
- The output will be displayed in the terminal.
Next steps
Install Python 3 Docker Container
You're done! Now that your container is ready, you may want to: