Compound Price Oracle

The Compound Price Oracle receives price updates from a poster (who pulls the prices from exchanges). The price oracle verifies the prices are within valid ranges, and if so, stores the prices so they can be accessed by the Compound Money Market.

See the Compound Price Oracle Specification, explaining in plain English how the protocol operates.

Contracts

We detail a few of the core contracts in the Compound protocol.

Price Oracle

The Compound Price Oracle.

Careful Math

Library for safe math operations.

ErrorReporter

Library for tracking error codes and failure conditions.

Exponential

Library for handling fixed-point decimal numbers.

Installation

To run the price oracle, pull the repository from GitHub and install its dependencies. You will need yarn or npm installed.

git clone https://github.com/compound-finance/compound-oracle
cd compound-oracle
yarn

You can then compile and deploy the contracts with:

truffle compile
POSTER_ADDRESS="0x..." truffle migrate

Testing

Contract tests are defined under the test directory. To run the tests run:

scripts/test

or with inspection (visit chrome://inspect) and look for a remote target after running:

node --inspect node_modules/truffle-core/cli.js test

Assertions used in our tests are provided by ChaiJS.

Code Coverage

To run code coverage, simply run:

scripts/coverage

Linting

To lint the code, run:

scripts/lint

Deployment

To deploy the Price Oracle run:

./scripts/blockchain deploy development <address-of-price-poster>

For development, <address-of-price-poster> will default to first unlocked account.

Docker

To run in docker:

# Build the docker image
docker build -t price-oracle .

# Run a shell to the built image
docker run -it price-oracle /bin/sh

From within a docker shell, you can interact locally with the protocol via ganache and truffle:

> ganache-cli &
> truffle deploy
> truffle console
truffle(development)> const {getDeployedAddress} = require("./scripts/javascript/deployUtils")
truffle(development)> priceOracleAddress=getDeployedAddress('development', 'PriceOracle')
truffle(development)> priceOracle = PriceOracle.at(priceOracleAddress)
truffle(development)> priceOracle.poster.call()
'0x842e5e1a348eb91fc68219ca70db83170ccd9a5e'

Test net

To deploy on test-net, run:

RINKEBY_PRIVATE_KEY=<...> scripts/blockchain/deploy rinkeby <poster-address>

where the private key refers to a rinkeby private key in hex form (e.g. this can be the value exported from MetaMask under Settings).

You can choose "rinkeby", "kovan" or "ropsten" as your test net.

Additionally, for not main-net, you can put your test-net private keys in a folder and set the environment variable (e.g. in your ~/.bash_profile):

ETHEREUM_NETWORKS_HOME=~/.ethereum

The project will search this directory for test-net keys, which you can add as such:

mkdir -p ~/.ethereum
# Store command via editor or:
pbpaste > ~/.ethereum/rinkeby
chmod 600 ~/.ethereum/rinkeby

Note: This method is not safe for production. Production keys should be kept on hardware wallets.

Development

Note: it's advised to use the deployment code in money-market. This code will merge the configuration of the price oracle with the money market itself.

For local development need a private key and address pair for the "poster."

compound-oracle> scripts/blockchain/deploy development <poster-address> # deploys price oracle to local ganache

This will deploy the price oracle and print its location to the console. That address will also be available in networks/development.json.

In your money market, you'll need to set this new oracle as the price oracle:

compound-money-market> scripts/blockchain/set-oracle <price-oracle-address>

Discussion

For any concerns with the protocol, open an issue or visit us on Discord to discuss.

For security concerns, please email security@compound.finance.

© Copyright 2018, Compound Labs