StarkNet-Open-Oracle

What is the Open Oracle standard?

Compound and Coinbase were tired with the status quo of black box off-chain oracles on Ethereum so they collaborated to create the open oracle standard. This initiative created an open standard that anyone could use to trustlessly bring data on-chain, without requiring custom integrations with data sources or relying on third parties for secure data.

It allows a Source (also called a Reporter) (typically a trusted source like an exchange) to sign a message containing price data in a standardized way with a private key.

A Publisher can then use this signed message to put the price data on-chain.

Using the Source's public key to verify the message's signature, there is no need to trust the Publisher for correctly reporting the data from the Source.

In April 2020, Coinbase started providing an Open Oracle compatible signed price feed so that anyone can publish their data on chain. They were followed by OKX the same year.

This repository ports the on-chain verification contracts of the standard from Ethereum over to StarkNet.

Setup for development

Install Protostar. Clone the repository. Use python 3.7.

python -m venv env
source env/bin/activate
pip install -r requirements.txt

Testing contracts (local contract deployment with protostar cool features takes some time so be patient)

protostar test tests/

Use protostar test --disable-hint-validation tests/ if using hints in the main Contract.

Using the client to publish signed prices

First, compile the contracts. The compiled contracts and their ABI will be stored in the build/ directory.

protostar build

1. Use a Starknet account with modified nonce validation

Due to some Starknet limitations, it is not possible yet to do multiple contract calls in one transaction with the Open Oracle contracts.
This should be fixed when the keccak builtin will be out along with other scalability improvements.

In order to send multiple transactions at the same time from the python client, you will need a special type of account with a modified type of nonce.

Here are the steps to create and deploy this type of account :

python contracts/account/private_key_gen.py

Retrieve the STARKNET_PRIVATE_KEY and the STARKNET_PUBLIC_KEY from the output. Then deploy your account with your public key as input parameter for the constructor :

protostar deploy build/AccountTimestampNonce.json -i STARKNET_PUBLIC_KEY --network alpha-goerli

Retrieve the Contract address you will get as an output.

Don't forget to send some ETH to this address for the gas fees.

2. Use the client to publish prices

2.1. Fill the envirnonment variables

You should now be able to fill the necessary environment variables in client/.env(fill_and_rename_to.env
Don't forget to rename the file to just .env when you are done!

Fill it using :

• your StarkNet account private key as an integer
• your StarkNet account contract address
• optionally, Coinbase API keys with “view” permission if you want to fetch signed prices from Coinbase. Note that OKX doesn't require any API keys to fetch its signed prices.

2.2. Choose the assets and sources you need

After that, edit the function main() in client/main.py so you can choose your assets, and if you want to fetch prices either from:

• OKX (use c.publish_open_oracle_entries_okx_sequential)
• Coinbase (use c.publish_open_oracle_entries_coinbase_sequential)
• both (use c.publish_open_oracle_entries_all_publishers_sequential).

Supported assets are:

• BTC, ETH, DAI, ZRX, BAT, KNC, LINK, COMP (for both Coinbase and OKX)
• XTZ, REP, UNI, GRT, SNX. (for Coinbase only)

async def main():
    c = OpenOracleClient()
    await c.publish_open_oracle_entries_all_publishers_sequential(assets=['btc', 'eth'])

2.3. Run either locally or with Docker

- Locally

Make sure you have activated the virtual env and just run

python client/main.py

- With a Docker container

docker build -t python-open-oracle-client .
docker run --env-file client/.env  python-open-oracle-client

Contract deployment and current address

To deploy the contract, just use protostar like this:

protostar build
protostar deploy build/OpenOraclePublisher.json --network alpha-goerli

The current version of the contract is deployed here: https://goerli.voyager.online/contract/0x010660d8f0c7403d696e5b3fdca2ef6630f9cd8102f9d3dd4cc65a82904aa8d7

The contract address is also stored in the variable OPEN_ORACLE_ADDRESS in client/main.py.