Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

Using the Elastic Beanstalk Python platform

This topic describes how to configure, build, and run your Python applications on Elastic Beanstalk.

Amazon Elastic Beanstalk supports a number of platform branches for different versions of the Python programming language. See Python in the Amazon Elastic Beanstalk Platforms document for a full list.

The Python web applications can run behind a proxy server with WSGI. Elastic Beanstalk provides Gunicorn as the default WSGI server.

You can add a Procfile to your source bundle to specify and configure the WSGI server for your application. For details, see Configuring the WSGI server with a Procfile on Elastic Beanstalk.

You can use the Pipfile and Pipfile.lock files created by Pipenv to specify Python package dependencies and other requirements. For details about specifying dependencies, see Specifying dependencies using a requirements file on Elastic Beanstalk.

Elastic Beanstalk provides configuration options that you can use to customize the software that runs on the EC2 instances in your Elastic Beanstalk environment. You can configure environment variables needed by your application, enable log rotation to Amazon S3, and map folders in your application source that contain static files to paths served by the proxy server.

Configuration options are available in the Elastic Beanstalk console for modifying the configuration of a running environment. To avoid losing your environment's configuration when you terminate it, you can use saved configurations to save your settings and later apply them to another environment.

To save settings in your source code, you can include configuration files. Settings in configuration files are applied every time you create an environment or deploy your application. You can also use configuration files to install packages, run scripts, and perform other instance customization operations during deployments.

Settings applied in the Elastic Beanstalk console override the same settings in configuration files, if they exist. This lets you have default settings in configuration files, and override them with environment-specific settings in the console. For more information about precedence, and other methods of changing settings, see Configuration options.

For Python packages available from pip, you can include a requirements file in the root of your application source code. Elastic Beanstalk installs any dependency packages specified in a requirements file during deployment. For details, see Specifying dependencies using a requirements file on Elastic Beanstalk.

For details about the various ways you can extend an Elastic Beanstalk Linux-based platform, see Extending Elastic Beanstalk Linux platforms.

Configuring your Python environment

The Python platform settings let you fine-tune the behavior of your Amazon EC2 instances. You can edit the Elastic Beanstalk environment's Amazon EC2 instance configuration using the Elastic Beanstalk console.

Use the Elastic Beanstalk console to configure Python process settings, enable Amazon X-Ray, enable log rotation to Amazon S3, and configure variables that your application can read from the environment.

Python settings

Amazon X-Ray settings

Log options

The Log Options section has two settings:

Static files

To improve performance, you can use the Static files section to configure the proxy server to serve static files (for example, HTML or images) from a set of directories inside your web application. For each directory, you set the virtual path to directory mapping. When the proxy server receives a request for a file under the specified path, it serves the file directly instead of routing the request to your application.

For details about configuring static files using configuration files or the Elastic Beanstalk console, see Serving static files.

By default, the proxy server in a Python environment serves any files in a folder named static at the /static path. For example, if your application source contains a file named logo.png in a folder named static, the proxy server serves it to users at subdomain.elasticbeanstalk.com/static/logo.png. You can configure additional mappings as explained in this section.

Environment properties

You can use environment properties to provide information to your application and configure environment variables. For example, you can create an environment property named CONNECTION_STRING that specifies a connection string that your application can use to connect to a database.

Inside the Python environment running in Elastic Beanstalk, these values are accessible using Python's os.environ dictionary. For more information, see http://docs.python.org/library/os.html.

You can use code that looks similar to the following to access the keys and parameters:

import os
endpoint = os.environ['API_ENDPOINT']

Environment properties can also provide information to a framework. For example, you can create a property named DJANGO_SETTINGS_MODULE to configure Django to use a specific settings module. Depending on the environment, the value could be development.settings, production.settings, etc.

See Environment properties and other software settings for more information.

Python configuration namespaces

You can use a configuration file to set configuration options and perform other instance configuration tasks during deployments. Configuration options can be platform specific or apply to all platforms in the Elastic Beanstalk service as a whole. Configuration options are organized into namespaces.

The Python platform defines options in the aws:elasticbeanstalk:environment:proxy, aws:elasticbeanstalk:environment:proxy:staticfiles, and aws:elasticbeanstalk:container:python namespaces.

The following example configuration file specifies configuration option settings to create an environment property named DJANGO_SETTINGS_MODULE, choose the Apache proxy server, specify two static files options that map a directory named statichtml to the path /html and a directory named staticimages to the path /images, and specify additional settings in the aws:elasticbeanstalk:container:python namespace. This namespace contains options that let you specify the location of the WSGI script in your source code, and the number of threads and processes to run in WSGI.

option_settings:
  aws:elasticbeanstalk:application:environment:
    DJANGO_SETTINGS_MODULE: production.settings
  aws:elasticbeanstalk:environment:proxy:
    ProxyServer: apache
  aws:elasticbeanstalk:environment:proxy:staticfiles:
    /html: statichtml
    /images: staticimages
  aws:elasticbeanstalk:container:python:
    WSGIPath: ebdjango.wsgi:application
    NumProcesses: 3
    NumThreads: 20

Configuration files also support several keys to further modify the software on your environment's instances. This example uses the packages key to install Memcached with yum and container commands to run commands that configure the server during deployment:

packages:
  yum:
    libmemcached-devel: '0.31'

container_commands:
  collectstatic:
    command: "django-admin.py collectstatic --noinput"
  01syncdb:
    command: "django-admin.py syncdb --noinput"
    leader_only: true
  02migrate:
    command: "django-admin.py migrate"
    leader_only: true
  03wsgipass:
    command: 'echo "WSGIPassAuthorization On" >> ../wsgi.conf'
  99customize:
    command: "scripts/customize.sh"

Elastic Beanstalk provides many configuration options for customizing your environment. In addition to configuration files, you can also set configuration options using the console, saved configurations, the EB CLI, or the Amazon CLI. See Configuration options for more information.