Managing and deploying Python applications

Compatibility notice

This documentation applies only to the following plans: proSpace, Space Server.

Starting a Python application

mStudio UI

To start a Python application from the mStudio, follow these steps:

1. Navigate to the project that you want to create the application in.
2. Select the "Apps" menu item in the sidebar.
3. Click the "Create App" button and select "Custom Python app".
4. In the installation wizard, select the entrypoint command that should be used to start your application and complete the wizard.

After the installation has completed, observe the installation directory in the UI.

CLI

To start a Python application from the CLI, run the following command:

$ mw app create python --wait --entrypoint "python server.py"

The --wait flag will cause the CLI to wait until the installation has completed. The --entrypoint flag will cause the CLI to configure the specified entrypoint command as the command that should be used to start your application. If omitted, the default entrypoint command yarn start will be used.

After the installation has completed, use the mw app get command to observe the installation directory.

API

To learn how to deploy a Python application via the API, read the article "Starting a Node.js or Python application".

Deploying your app

After you have created your Python app, you can deploy your code by moving it into the designated application directory. You may use any method that you prefer to deploy your code, such as a local Git clone, rsync or SFTP.

Have a look at our collection of deployment guides for more information on how to deploy your code.

info

Since the deployment of your application is optimized for production usage, the platform will NOT automatically restart your application on code changes. You will need to restart your application manually after you have deployed your code. See the section on managing your process lifecycle for more information.

Making your app accessible via HTTP

See our guide on Running Webservers to learn how to make your Python app accessible via HTTP.

Managing your process lifecycle

See our guide on Running Webservers to learn how to manage the process lifecycle of your Python application.

Example applications

Flask with Gunicorn

This section shows you how to deploy a simple Python application using Flask and Gunicorn. For this, you need to create a custom Python installation with the entrypoint command gunicorn -w4 server:app:

Local shell session

$ mw app create python --wait --entrypoint "gunicorn -w4 server:app"

Regarding the entrypoint:

• The -w parameter controls the amount of worker processes. The Gunicorn documentation recommends using 2 × [number of CPU cores] + 1 as a starting point.
• The server:app part refers to the app object in the server.py file. These will be created in the next step.

First, install the required dependencies via pip:

SSH shell session

$ pip install gunicorn flask

Then, create a server.py in your application directory:

server.py

from flask import Flask

app = Flask(__name__)

@app.route("/")
def hello():
    return "<p>Hello World</p>"

Gunicorn will automatically respect the PORT environment variable, so you don't need to specify the port in your application code.

To make sure your app is running, use the mittnitectl job status and mittnitectl job start commands:

SSH shell session

$ mittnitectl job status
$ mittnitectl job start

Django with Gunicorn

This section shows you how to deploy a simple Python application using Django and Gunicorn. For this, you need to create a custom python installation with the entrypoint command gunicorn -w 4 <project-name>.wsgi:application. In this command, the -w parameter controls the amount of worker processes, and <project-name> is the name of your Django project:

Local shell session

$ mw app create python --wait --entrypoint "gunicorn -w 4 <project-name>.wsgi:application"

Regarding the entrypoint:

• The -w parameter controls the amount of worker processes. The Gunicorn documentation recommends using 2 × [number of CPU cores] + 1 as a starting point.
• <project-name> is the name of your Django project. When you create a new Django project yourself, this is the first argument you pass to the django-admin startproject command.

Follow the official Django tutorial to learn how to initialize a Django project. In short, to initialize a new project in your application directory, use the following command:

SSH shell session

$ django-admin startproject <project-name> .

Gunicorn will automatically respect the PORT environment variable, so you don't need to specify the port in your application code.

To make sure your app is running, use the mittnitectl job status and mittnitectl job start commands:

SSH shell session

$ mittnitectl job status
$ mittnitectl job start

Django development server

When working with Django, you can also use the built-in development server. The development server is not suitable for production use, but is useful for development and testing purposes, because it automatically reloads on code changes.

To use the development server, you need to create a wrapper script to correctly read the PORT environment variable. Create your Python app with the entrypoint bash start.sh:

Local shell session

$ mw app create python --wait --entrypoint "bash start.sh"

Then, initialize your Django app as described in the previous section, and create a start.sh file in your application directory:

start.sh

#!/bin/bash

exec python manage.py runserver ${PORT:-8000}