What is Polaris?¶
Polaris is a django reusable-app implementing SEP-24 maintained by the Stellar Development Foundation (SDF). SEP-24 is a standard defined to make wallets and anchors interoperable, meaning any wallet can communicate with any anchor for the purpose of withdrawing or depositing assets into the stellar network.
Polaris is not a library or a framework; its an extendable django reusable-app. Like many django apps, it comes with fully-implemented endpoints, templates, and database models. The project is completely open source and available at the SDF’s github.
Polaris does not aim to give you full control of the SEP-24 implementation. Instead, Polaris provides provides developers the ability to integrate with the already-implemented functionality, similar to a framework.
The source code for a functional example of a django project running Polaris can be found under the example folder on github.
Installation and Configuration¶
First make sure you have
cd’ed into your django project’s main directory
and then run
pip install django-polaris
Add the following to
INSTALLED_APPS in settings.py. Any app that overrides
a static asset in Polaris should be listed before “polaris”. This ensures that
django will find your asset before the Polaris default.
INSTALLED_APPS = [ ..., "django.contrib.staticfiles", "corsheaders", "rest_framework", "sass_processor", "polaris", ]
Add Polaris’ PolarisSameSiteMiddleware,
LocaleMiddleware to your
SessionMiddleware must be listed below
MIDDLEWARE = [ ..., 'polaris.middleware.PolarisSameSiteMiddleware', 'django.contrib.sessions.middleware.SessionMiddleware', 'django.middleware.locale.LocaleMiddleware', 'corsheaders.middleware.CorsMiddleware', ... ]
Add the variables necessary for internationalization in settings.py:
USE_I18N = True USE_L10N = True USE_THOUSAND_SEPARATOR = True LANGUAGES = [("en", _("English"))]
Polaris supports English and Portuguese out of the box. If you’d like to add
support for another language, make a pull request to Polaris with the necessary
translation files. If Polaris supports the language you wish to provide, make
sure the text content rendered from your app supports translation to that language,
and add it to
PROJECT_ROOT in your project’s settings.py. Polaris uses this to
PROJECT_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
Add the following to your settings.py as well:
FORM_RENDERER = "django.forms.renderers.TemplatesSetting" STATIC_ROOT = os.path.join(BASE_DIR, "<your static root directory>") STATIC_URL = "<your static url path>" STATICFILES_STORAGE = "whitenoise.storage.CompressedManifestStaticFilesStorage" STATICFILES_FINDERS = [ "django.contrib.staticfiles.finders.FileSystemFinder", "django.contrib.staticfiles.finders.AppDirectoriesFinder", "sass_processor.finders.CssFinder", ] SASS_PROCESSOR_ROOT = STATIC_ROOT DEFAULT_PAGE_SIZE = <your default page size>
This allows Polaris to override django’s default HTML widgets to provide a great UI out of the box. See the Static Files django page for more information.
Polaris uses several environment variables that should be defined in the
environment or included in
DJANGO_SECRET_KEY="yoursupersecretkey" DJANGO_DEBUG=True ASSETS="USD" USD_DISTRIBUTION_ACCOUNT_SEED="" USD_ISSUER_ACCOUNT_ADDRESS="" STELLAR_NETWORK_PASSPHRASE="Test SDF Network ; September 2015" HORIZON_URI="https://horizon-testnet.stellar.org/" SERVER_JWT_KEY="yoursupersecretjwtkey" HOST_URL="https://example.com"
Polaris supports anchoring one or multiple assets on the Stellar network.
should be a comma-separated list of asset codes such as “USD”, “ETH”, or “MYCOIN”.
For every asset code listed, you should add a pair of variables for the distribution account’s private key and issuer account’s public key. Note that each pair of variable names should be prepended with the asset code. The SDF has built a small CLI tool for creating these accounts on testnet.
Python Code and Bash Commands¶
Add the Polaris endpoints in
import polaris.urls from django.urls import path, include urlpatterns = [ ..., path("", include(polaris.urls)), ]
python manage.py migrate
python manage.py compilescss
python manage.py collectstatic --no-input
python manage.py compilemessages
The last step is to add an
Asset database object for the token you
intend to anchor. Get into the django python shell like so:
python manage.py shell, then:
from polaris.models import Asset Asset.objects.create( code="USD", issuer="<the issuer address>", significant_digits=2, deposit_fee_fixed=1, deposit_fee_percent=2, withdraw_fee_fixed=1, withdraw_fee_percent=2, deposit_min_amount=10, deposit_max_amount=10000, withdrawal_min_amount=10, withdrawal_min_amount=10000 )
See the Asset documentation for more information on the fields used.
You are now ready to run the Polaris anchor server!
Running the Server Locally¶
Polaris is an HTTPS-only server, so to run it locally you must have a self-signed SSL certificate and configure your browser to trust it.
Run this command to generate a self-signed certificate for localhost:
openssl req -x509 -out localhost.crt -keyout localhost.key \ -newkey rsa:2048 -nodes -sha256 \ -subj '/CN=localhost' -extensions EXT -config <( \ printf "[dn]\nCN=localhost\n[req]\ndistinguished_name = dn\n[EXT]\nsubjectAltName=DNS:localhost\nkeyUsage=digitalSignature\nextendedKeyUsage=serverAuth")
Then, instead of using the usual
runserver command, Polaris comes with the
runsslserver command. Just add the app to your
INSTALLED_APPS = [ ..., "polaris", "sslserver" ]
Finally, run these commands in separate windows, or run them all in the background:
python manage.py runsslserver --certificate <path to localhost.crt> --key <path to localhost.key> python manage.py watch_transactions python manage.py check_trustlines --loop python manage.py poll_pending_deposits --loop
The other three processes perform various functions needed to run a fully-functioning anchor, like periodically checking for which pending deposits are ready to be executed on the stellar network.
At this point, you need to start implementing the integration points Polaris provides. Check out the Integrations section for more information.
To set up the development environment, fork the repository, then:
cd django-polaris docker-compose build docker-compose up
You should now have a minimal anchor server running on port 8000. When you make changes locally, the docker containers will restart with the updated code. Your browser may complain about the service using a self-signed certificate for HTTPS. You can resolve this by marking the certificate used by the service as trusted.
You can install the dependencies locally in a virtual environment:
pip install pipenv cd django-polaris pipenv install --dev pipenv run pytest -c polaris/pytest.ini
Or, you can simply run the tests from inside the docker container. However, this may be slower.
docker exec -it <image ID> pipenv run pytest
Submit a PR¶
After you’ve made your changes, push them to you a remote branch and make a Pull Request on the stellar/django-polaris master branch.