Welcome to Polaris¶
To get a SEP-24 anchor server running quickly, see the tutorial.
For important updates on Polaris’ development and releases please join the email list.
The documentation below outlines the common set up needed for any Polaris deployment, but each SEP implementation has its own configuration and integration requirements. These requirements are described in the documentation for each SEP.
What is Polaris?¶
Polaris is an extendable django app for Stellar Ecosystem Proposal (SEP) implementations maintained by the Stellar Development Foundation (SDF). Using Polaris, you can run a web server supporting any combination of SEP-1, 6, 10, 12, 24, and 31.
While Polaris implements the majority of the functionality described in each SEP, there are pieces of functionality that can only be implemented by the developer using Polaris. For example, only an anchor can implement the integration with their partner bank.
This is why each SEP implemented by Polaris comes with a programmable interface for developers to inject their own business logic.
Polaris is completely open source and available on github. The SDF also runs a reference server using Polaris that can be tested using our demo client.
Installation and Configuration¶
These instructions assume you have already set up a django project. If you haven’t,
take a look at the Django docs. It also assumes you have a database configured
from the project’s settings.py
.
First make sure you have cd
’ed into your django project’s main directory
and then run
pip install django-polaris
Settings¶
Add the following to INSTALLED_APPS
in settings.py.
INSTALLED_APPS = [
...,
"corsheaders",
"rest_framework",
"polaris",
]
Add CorsMiddleware
to your settings.MIDDLEWARE
. It should be listed above
other middleware that can return responses such as CommonMiddleware
.
MIDDLEWARE = [
...,
'corsheaders.middleware.CorsMiddleware',
...
]
Polaris will accept requests from all origins to its endpoints. It does this by adding corsheaders signal that checks the request URI. However this does not change the CORS policy for any other endpoint on the server. You can change this functionality using the settings listed in the corsheaders documentation.
Optionally, you can add Polaris’ logger to your LOGGING configuration. For example:
LOGGING = {
'version': 1,
'disable_existing_loggers': False,
'formatters': {
'simple': {
'format': '{levelname} {message}',
'style': '{',
},
},
'handlers': {
'console': {
'level': 'DEBUG',
'class': 'logging.StreamHandler',
'formatter': 'simple'
}
},
'loggers': {
'myapp': {
'handlers': ['console'],
'propogate': True,
'LEVEL': 'DEBUG'
},
'polaris': {
'handlers': ['console'],
'propagate': True,
'LEVEL': 'INFO'
},
}
}
You may want to configure the LEVEL
of the Polaris logger differently depending on whether you’re running the service locally or in production. One way to do this by reading a POLARIS_LOG_LEVEL
variable, or something similar, from the project’s environment.
Environment Variables¶
Some environment variables are required for all Polaris deployments, some are required for a specific set of SEPs, and others are optional.
Environment variables can be set within the environment itelf, in a .env
file, or specified in your Django settings file.
A .env
file must be within the directory specified by Django’s BASE_DIR
setting or specified explitly using the POLARIS_ENV_PATH
setting.
To set the variables in the project’s settings file, the variable name must be prepended with POLARIS_
. Make sure not to put sensitive information in the project’s settings file, such as Stellar secret keys, encryption keys, etc.
- ACTIVE_SEPS: Required
A list of Stellar Ecosystem Proposals (SEPs) to run using Polaris. Polaris uses this list to configure various aspects of the deployment, such as the endpoint available and settings required.
Ex.
ACTIVE_SEPS=sep-1,sep-10,sep-24
- LOCAL_MODE
A boolean value indicating if Polaris is in a local environment. Defaults to
False
. The value will be read from the environment usingenviron.Env.bool()
.Ex.
LOCAL_MODE=True
,LOCAL_MODE=1
- HORIZON_URI
A URL (protocol + hostname) for the Horizon instance Polaris should connect to.
Defaults to
https://horizon-testnet.stellar.org
.Ex.
HORIZON_URI=https://horizon.stellar.org
- HOST_URL : Required
The URL (protocol + hostname) that this Polaris instance will run on.
Ex.
HOST_URL=https://testanchor.stellar.org
,HOST_URL=http://localhost:8000
- SEP10_HOME_DOMAINS
A list of home domains (no protocol, only hostname) that Polaris should consider valid when verifying SEP-10 challenge transactions sent by clients. The first domain will be used to build SEP-10 challenge transactions if the client request does not contain a
home_domain
parameter. Polaris will reject client requests that contain ahome_domain
value not included in this list. The value will be read from the environment usingenviron.Env.list()
.Defaults to a list containing the hostname of
HOST_URL
defined above if not specified.Ex.
SEP10_HOME_DOMAINS=testanchor.stellar.org,example.com
- SERVER_JWT_KEY : Required for SEP-10
A secret string used to sign the encoded SEP-10 JWT contents. This should not be checked into version control.
Ex.
SERVER_JWT_KEY=supersecretstellarjwtsecret
- SIGNING_SEED : Required for SEP-10
A Stellar secret key used to sign challenge transactions before returning them to clients. This should not be checked into version control.
Ex.
SIGNING_SEED=SAEJXYFZOQT6TYDAGXFH32KV6GLSMLCX2E2IOI3DXY7TO2O63WFCI5JD
- STELLAR_NETWORK_PASSHRASE
The string identifying the Stellar network to use.
Defaults to
Test SDF Network ; September 2015
.Ex.
STELLAR_NETWORK_PASSPHRASE="Public Global Stellar Network ; September 2015"
- MAX_TRANSACTION_FEE_STROOPS
An integer limit for submitting Stellar transactions. Increasing this will decrease the probability of Horizon rejecting a transaction due to a Timeout Error, which means the Stellar Network selected transactions offering higher fees.
Defaults to the return value Python SDK’s
Server().fetch_base_fee()
source, which is the most recent ledger’s base fee, usually 100.Ex.
MAX_TRANSACTION_FEE_STROOPS=300
- CALLBACK_REQUEST_TIMEOUT
An integer for the number of seconds to wait before canceling a server-side callback request to
Transaction.on_change_callback
if present. Only used for SEP-6 and SEP-24. Polaris makes server-side requests toTransaction.on_change_callback
from CLI commands such aspoll_pending_deposits
andexecute_outgoing_transactions
. Server-side callbacks requests are not made from the API server.Defaults to 3 seconds.
Ex.
CALLBACK_REQUEST_TIMEOUT=10
- CALLBACK_REQUEST_DOMAIN_DENYLIST
- A list of home domains to check before accepting an
on_change_callback
parameter in SEP-6 and SEP-24 requests. This setting can be useful when a client is providing a callback URL that consistently reaches the CALLBACK_REQUEST_TIMEOUT limit, slowing down the rate at which transactions are processed. Requests containing denied callback URLs will not be rejected, but the URLs will not be saved toTransaction.on_change_callback
and requests will not be made. - SEP6_USE_MORE_INFO_URL
A boolean value indicating whether or not to provide the
more_info_url
response attribute in SEP-6GET /transaction(s)
responses and make thesep6/transaction/more_info
endpoint available.Defaults to
False
.Ex.
SEP6_USE_MORE_INFO_URL=1
,SEP6_USE_MORE_INFO_URL=True
Endpoints¶
Add the Polaris endpoints in urls.py
import polaris.urls
from django.urls import path, include
urlpatterns = [
...,
path("", include(polaris.urls)),
]
Database Models¶
Polaris works with all major relational databases, and the psycopg2 PostgreSQL driver in installed out-of-the-box. If you find Polaris attempts to make queries incompatible with your database, file an issue in the project’s github repository.
Run migrations to create these tables in your database.
python manage.py migrate
Now, create an Asset
database object for each asset you intend to anchor. Get
into your python shell, then run something like this:
from polaris.models import Asset
Asset.objects.create(
code="USD",
issuer="<the issuer address>",
distribution_seed="<distribution account secret key>",
sep24_enabled=True,
...
)
The distribution_seed
and channel_seed
columns are encrypted at the database layer
using Fernet symmetric encryption, and only decrypted when held in memory within an
Asset
object. It uses your Django project’s SECRET_KEY
setting to generate the
encryption key, so make sure its value is unguessable and kept a secret.
See the Asset documentation for more information on the fields used.
At this point, you should configure Polaris for one or more of the SEPs currently supported. Once configured, check out how to run the server as described in the next section.
Running the Web Server¶
Production¶
Polaris should only be deployed using HTTPS in production. You should do this by using a HTTPS web server or running Polaris behind a HTTPS reverse proxy. The steps below outline the settings necessary to ensure your deployment is secure.
To redirect HTTP traffic to HTTPS, add the following to settings.py:
SECURE_SSL_REDIRECT = True
And if you’re running Polaris behind a HTTPS proxy:
SECURE_PROXY_SSL_HEADER = ('HTTP_X_FORWARDED_PROTO', 'https')
This tells Django what header to check and what value it should be in order to consider the incoming request secure.
Local Development¶
Locally, Polaris can be run using Django’s HTTP development server
python manage.py runserver
If you’re using Polaris’ SEP-24 support, you also need to use the following environment variable:
LOCAL_MODE=1
This is necessary to disable SEP-24’s interactive flow authentication mechanism, which requires HTTPS. Do not use local mode in production.
Contributing¶
To set up the development environment or run the SDF’s reference server, run follow the instructions below.
git clone git@github.com:stellar/django-polaris.git
cd django-polaris
Then, add a .env
file in the example
directory. You’ll need to create
a signing account on Stellar’s testnet and add it to your environment variables.
DJANGO_SECRET_KEY=supersecretdjangokey
DJANGO_DEBUG=True
SIGNING_SEED=<your signing account seed>
STELLAR_NETWORK_PASSPHRASE="Test SDF Network ; September 2015"
HORIZON_URI="https://horizon-testnet.stellar.org/"
SERVER_JWT_KEY=yourjwtencryptionsecret
DJANGO_ALLOWED_HOSTS=localhost,0.0.0.0,127.0.0.1
HOST_URL="http://localhost:8000"
LOCAL_MODE=True
SEP10_HOME_DOMAINS=localhost:8000
Next, you’ll need to create an asset on the Stellar test network and setup a distribution account. Polaris offers a CLI command that allows developers to issue assets on testnet. See the CLI Commands documentation for more information.
Now you’re ready to add your asset to Polaris. Run the following commands:
$ docker-compose build
$ docker-compose up server
Go to http://localhost:8000/admin and login with the default credentials (root, password).
Go to the Assets menu, and click “Add Asset”
Enter the code, issuer, and distribution seed for the asset. Enable the SEPs you want to test.
Click Save.
Finally, kill the current docker-compose
process and run a new one:
$ docker-compose up
You should now have a anchor server running on port 8000. When you make changes locally, the docker containers will restart with the updated code.
Testing¶
First, cd
into the polaris
directory and create an .env
file just like you did for example
. However, do not include LOCAL_MODE
and make sure all URLs use HTTPS. This is done because Polaris tests functionality that is only run when LOCAL_MODE
is not True
. When not in local mode, Polaris expects it’s URLs to be HTTPS.
Once you’ve created your .env
file, you can install the dependencies locally in a virtual environment:
pip install pipenv
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 server pytest -c polaris/pytest.ini
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 repository’s master branch. Note that Polaris uses the black code formatter, so please format your code before requesting us to merge your changes.