django-storage-swift: a storage layer for OpenStack Swift

django-storage-swift allows Django applications to use OpenStack Swift as a file storage layer.

Features

• Reads/writes files into/out of Swift.
• Automatically derives the correct URL to allow files to be accessed through a web browser based on information returned from the authorisation server.
  • Allows you to override the host, port and path as necessary.
  • Supports the generation of temporary URLs to restrict access to files.

Usage

You can install django-storage-swift through pip. To store your media files on swift, add the following line to your settings.py or local_settings.py:

DEFAULT_FILE_STORAGE = 'swift.storage.SwiftStorage'

To store your static files on swift, add the following line:

STATICFILES_STORAGE = 'swift.storage.StaticSwiftStorage'

This will use another container.

Configuring

django-storage-swift recognises the following options.

Option	Default	Description
SWIFT_AUTH_URL	Required	The URL for the auth server, e.g. http://127.0.0.1:5000/v2.0
SWIFT_USERNAME	Required	The username to use to authenticate.
SWIFT_KEY/SWIFT_PASSWORD	Required	The key (password) to use to authenticate.
SWIFT_AUTH_VERSION	None	The version of the authentication protocol to use. If no auth version is defined, a version will be guessed based on auth parameters.
SWIFT_TENANT_NAME/SWIFT_PROJECT_NAME	None	(v2 and v3 auth) The tenant/project name to use when authenticating.
SWIFT_TENANT_ID/SWIFT_PROJECT_ID	None	(v2 and v3 auth) The tenant/project id to use when authenticating.
SWIFT_USER_DOMAIN_NAME	None	(v3 auth only) The domain name we authenticate to
SWIFT_USER_DOMAIN_ID	None	(v3 auth only) The domain id we authenticate to
SWIFT_PROJECT_DOMAIN_NAME	None	(v3 auth only) The domain name our project is located in
SWIFT_PROJECT_DOMAIN_ID	None	(v3 auth only) The domain id our project is located in
SWIFT_REGION_NAME	None	OpenStack region if needed. Check with your provider.
SWIFT_CONTAINER_NAME	None	The container in which to store the files. (DEFAULT_FILE_STORAGE)
SWIFT_STATIC_CONTAINER_NAME	None	Alternate container for storing staticfiles. (STATICFILES_STORAGE)
SWIFT_AUTO_CREATE_CONTAINER	False	Should the container be created if it does not exist?
SWIFT_AUTO_CREATE_CONTAINER_PUBLIC	False	Set the auto created container as public on creation
SWIFT_AUTO_CREATE_CONTAINER_ALLOW_ORIGIN	None	Set the container's X-Container-Meta-Access-Control-Allow-Origin value, to support CORS requests.
SWIFT_AUTO_BASE_URL	True	Query the authentication server for the base URL.
SWIFT_BASE_URL	None	The base URL from which the files can be retrieved, e.g. http://127.0.0.1:8080/.
SWIFT_NAME_PREFIX	None	Prefix that gets added to all filenames.
SWIFT_USE_TEMP_URLS	False	Generate temporary URLs for file access (allows files to be accessed without a permissive ACL).
SWIFT_TEMP_URL_KEY	None	Temporary URL key --- see the OpenStack documentation.
SWIFT_TEMP_URL_DURATION	30*60	How long a temporary URL remains valid, in seconds.
SWIFT_EXTRA_OPTIONS	{}	Extra options, eg. { "endpoint_type": "adminURL" }, which will return adminURL instead publicURL.
SWIFT_STATIC_BASE_URL	None	The base URL from which the static files can be retrieved, e.g. http://127.0.0.1:8080/.
SWIFT_STATIC_NAME_PREFIX	None	Prefix that gets added to all static filenames.
SWIFT_CONTENT_TYPE_FROM_FD	False	Determine the files mimetypes from the actual content rather than from their filename (default).
SWIFT_FULL_LISTING	True	Ensures to get whole directory contents (by default swiftclient limits it to 10000 entries)
SWIFT_AUTH_TOKEN_DURATION	60*60*23	How long a token is expected to be valid in seconds.

SWIFT_BASE_URL

django-swift-storage will automatically query the authentication server for the URL where your files can be accessed, which takes the form http://server:port/v1/AUTH_token/.

Sometimes you want to override the server and port (for example if you're developing using devstack inside Vagrant). This can be accomplished with SWIFT_BASE_URL.

The provided value is parsed, and:

• host and port override any automatically derived values
• any path component is put before derived path components.

So if your auth server returns http://10.0.2.2:8080/v1/AUTH_012345abcd/ and you have SWIFT_BASE_URL="http://127.0.0.1:8888/foo", the url function will a path based on http://127.0.0.1:8888/foo/v1/AUTH_012345abcd/.

Temporary URLs

Temporary URLs provide a means to grant a user permission to access a file for a limited time only and without making the entire container public.

Temporary URLs work as described in the Swift documentation. (The code to generate the signatures is heavily based on their implementation.) They require setup of a key for signing: the process is described in the OpenStack documentation.

Use

Once installed and configured, use of django-storage-swift should be automatic and seamless.

You can verify that swift is indeed being used by running, inside python manage.py shell:

from django.core.files.storage import default_storage
default_storage.http_conn

The result should be <<swiftclient.client.Connection object ...>>

Openstack Keystone/Identity v3

To authenticate with a swift installation using Keystone AUTH and the Identity v3 API, you must also specify either the domain ID or name that your user and project (tenant) belongs to.

SWIFT_AUTH_URL='https://keystoneserver/v3'
SWIFT_AUTH_VERSION='3'
SWIFT_USERNAME='<<USERNAME>>'
SWIFT_KEY='<<PASSWORD>>'
SWIFT_TENANT_NAME='<<TENANT_NAME>>'
SWIFT_USER_DOMAIN_NAME='<<DOMAIN_NAME>>'
SWIFT_PROJECT_DOMAIN_NAME='<<DOMAIN_NAME>>'

Troubleshooting

• I'm getting permission errors accessing my files: If you are not using temporary URLs, you may need to make the container publically readable. See this helpful discussion. If you are using temporary URLs, verify that your key is set correctly.
• I'm getting empty or truncated file uploads: Issues with some content types may cause an incorrect content_length header to be sent with file uploads, resulting in 0 byte or truncated files. To avoid this, set SWIFT_CONTENT_LENGTH_FROM_FD: True.

Quickstart

# This was executed on a VM running a SAIO, for example with
# https://github.com/swiftstack/vagrant-swift-all-in-one

# Create two world-readable containers
swift post -r ".r:*" django
swift post -r ".r:*" django-static

# A virtualenv to keep installation separated
virtualenv sampleenv
source sampleenv/bin/activate
pip install django-storage-swift
pip install django

# Create a sample project
django-admin startproject sampleproj
export DJANGO_SETTINGS_MODULE=sampleproj.settings
cd sampleproj/

# A few required settings, using SAIO defaults
cat <<EOF >> sampleproj/settings.py
DEFAULT_FILE_STORAGE='swift.storage.SwiftStorage'
STATICFILES_STORAGE ='swift.storage.StaticSwiftStorage'
SWIFT_AUTH_URL='http://127.0.0.1:8080/auth/v1.0'
SWIFT_USERNAME='test:tester'
SWIFT_KEY='testing'
SWIFT_CONTAINER_NAME='django'
SWIFT_STATIC_CONTAINER_NAME='django-static'
EOF

# Create the initial DB data
python manage.py migrate

# This uploads static files to Swift
python manage.py collectstatic --noinput

# Now open http://127.0.0.1:8000/admin/ in your browser
# Static files like CSS are served by Swift
python manage.py runserver