Compound Protocol

The Compound Protocol is an Ethereum smart contract for supplying or borrowing assets. Through the cToken contracts, accounts on the blockchain supply capital (Ether or ERC-20 tokens) to receive cTokens or borrow assets from the protocol (holding other assets as collateral). The Compound cToken contracts track these balances and algorithmically set interest rates for borrowers.

Before getting started with this repo, please read:

• The Compound Whitepaper, describing how Compound works
• The Compound Protocol Specification, explaining in plain English how the protocol operates

For questions about interacting with Compound, please visit our Discord server.

For security concerns, please visit https://compound.finance/security or email [email protected].

Contributing

Contributing to the Compound protocol is a bit different than most open-source projects -- check out the community guide on Contributing.

Contracts

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

CToken, CErc20 and CEther

The Compound cTokens, which are self-contained borrowing and lending contracts. CToken contains the core logic and CErc20 and CEther add public interfaces for Erc20 tokens and ether, respectively. Each CToken is assigned an interest rate and risk model (see InterestRateModel and Comptroller sections), and allows accounts to *mint* (supply capital), *redeem* (withdraw capital), *borrow* and *repay a borrow*. Each CToken is an ERC-20 compliant token where balances represent ownership of the market.

Comptroller

The risk model contract, which validates permissible user actions and disallows actions if they do not fit certain risk parameters. For instance, the Comptroller enforces that each borrowing user must maintain a sufficient collateral balance across all cTokens.

Updating the Comptroller
• Follow the existing naming schema (ControllerGX)
• Update the scenario runner in scenario/src/Builder/ComptrollerImplBuilder.ts
• Create unit tests and fork simulations as necessary
• Call npx saddle deploy Comptroller -n mainnet to deploy to mainnet and generate new ABI
• The ABI can also be generated by deploying to mainnet in a fork simulation
• Call node script/comptroller-abi to merge the new Comptroller ABI with the Unitroller ABI
• Ensure that commit contains new generated Comptroller ABI

Comp

The Compound Governance Token (COMP). Holders of this token have the ability to govern the protocol via the governor contract.

Governor Alpha

The administrator of the Compound timelock contract. Holders of Comp token may create and vote on proposals which will be queued into the Compound timelock and then have effects on Compound cToken and Comptroller contracts. This contract may be replaced in the future with a beta version.

InterestRateModel

Contracts which define interest rate models. These models algorithmically determine interest rates based on the current utilization of a given market (that is, how much of the supplied assets are liquid versus borrowed).

Careful Math

Library for safe math operations.

ErrorReporter

Library for tracking error codes and failure conditions.

Exponential

Library for handling fixed-point decimal numbers.

SafeToken

Library for safely handling Erc20 interaction.

WhitePaperInterestRateModel

Initial interest rate model, as defined in the Whitepaper. This contract accepts a base rate and slope parameter in its constructor.

Installation

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

git clone https://github.com/compound-finance/compound-protocol
cd compound-protocol
yarn install --lock-file # or `npm install`

REPL

The Compound Protocol has a simple scenario evaluation tool to test and evaluate scenarios which could occur on the blockchain. This is primarily used for constructing high-level integration tests. The tool also has a REPL to interact with local the Compound Protocol (similar to truffle console).

yarn repl -n development
yarn repl -n rinkeby

> Read CToken cBAT Address
Command: Read CToken cBAT Address
AddressV<val=0xAD53863b864AE703D31b819d29c14cDA93D7c6a6>

You can read more about the scenario runner in the Scenario Docs on steps for using the repl.

Testing

Jest contract tests are defined under the tests directory. To run the tests run:

yarn test

Integration Specs

There are additional tests under the spec/scenario folder. These are high-level integration tests based on the scenario runner depicted above. The aim of these tests is to be highly literate and have high coverage in the interaction of contracts.

Formal Verification Specs

The Compound Protocol has a number of formal verification specifications, powered by Certora. You can find details in the spec/formal folder. The Certora Verification Language (CVL) files included are specifications, which when with the Certora CLI tool, produce formal proofs (or counter-examples) that the code of a given contract exactly matches that specification.

Code Coverage

To run code coverage, run:

yarn coverage

Linting

To lint the code, run:

yarn lint

Docker

To run in docker:

# Build the docker image
docker build -t compound-protocol .

# Run a shell to the built image
docker run -it compound-protocol /bin/sh

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

    /compound-protocol > yarn console -n goerli
    Using network goerli https://goerli-eth.compound.finance
    Saddle console on network goerli https://goerli-eth.compound.finance
    Deployed goerli contracts
      comptroller: 0x627EA49279FD0dE89186A58b8758aD02B6Be2867
      comp: 0xfa5E1B628EFB17C024ca76f65B45Faf6B3128CA5
      governorAlpha: 0x8C3969Dd514B559D78135e9C210F2F773Feadf21
      maximillion: 0x73d3F01b8aC5063f4601C7C45DA5Fdf1b5240C92
      priceOracle: 0x9A536Ed5C97686988F93C9f7C2A390bF3B59c0ec
      priceOracleProxy: 0xd0c84453b3945cd7e84BF7fc53BfFd6718913B71
      timelock: 0x25e46957363e16C4e2D5F2854b062475F9f8d287
      unitroller: 0x627EA49279FD0dE89186A58b8758aD02B6Be2867

    > await comp.methods.totalSupply().call()
    '10000000000000000000000000'

Console

After you deploy, as above, you can run a truffle console with the following command:

yarn console -n goerli

This command will start a saddle console conencted to Goerli testnet (see Saddle README):

    Using network goerli https://goerli.infura.io/v3/e1a5d4d2c06a4e81945fca56d0d5d8ea
    Saddle console on network goerli https://goerli.infura.io/v3/e1a5d4d2c06a4e81945fca56d0d5d8ea
    Deployed goerli contracts
      comptroller: 0x627EA49279FD0dE89186A58b8758aD02B6Be2867
      comp: 0xfa5E1B628EFB17C024ca76f65B45Faf6B3128CA5
      governorAlpha: 0x8C3969Dd514B559D78135e9C210F2F773Feadf21
      maximillion: 0x73d3F01b8aC5063f4601C7C45DA5Fdf1b5240C92
      priceOracle: 0x9A536Ed5C97686988F93C9f7C2A390bF3B59c0ec
      priceOracleProxy: 0xd0c84453b3945cd7e84BF7fc53BfFd6718913B71
      timelock: 0x25e46957363e16C4e2D5F2854b062475F9f8d287
      unitroller: 0x627EA49279FD0dE89186A58b8758aD02B6Be2867
    > await comp.methods.totalSupply().call()
    '10000000000000000000000000'

Deploying a CToken from Source

Note: you will need to set ~/.ethereum/<network> with your private key or assign your private key to the environment variable ACCOUNT.

Note: for all sections including Etherscan verification, you must set the ETHERSCAN_API_KEY to a valid API Key from Etherscan.

To deploy a new cToken, you can run the token:deploy. command, as follows. If you set VERIFY=true, the script will verify the token on Etherscan as well. The JSON here is the token config JSON, which should be specific to the token you wish to list.

npx saddle -n rinkeby script token:deploy '{
  "underlying": "0x577D296678535e4903D59A4C929B718e1D575e0A",
  "comptroller": "$Comptroller",
  "interestRateModel": "$Base200bps_Slope3000bps",
  "initialExchangeRateMantissa": "2.0e18",
  "name": "Compound Kyber Network Crystal",
  "symbol": "cKNC",
  "decimals": "8",
  "admin": "$Timelock"
}'

If you only want to verify an existing token an Etherscan, make sure ETHERSCAN_API_KEY is set and run token:verify with the first argument as the token address and the second as the token config JSON:

npx saddle -n rinkeby script token:verify 0x19B674715cD20626415C738400FDd0d32D6809B6 '{
  "underlying": "0x577D296678535e4903D59A4C929B718e1D575e0A",
  "comptroller": "$Comptroller",
  "interestRateModel": "$Base200bps_Slope3000bps",
  "initialExchangeRateMantissa": "2.0e18",
  "name": "Compound Kyber Network Crystal",
  "symbol": "cKNC",
  "decimals": "8",
  "admin": "$Timelock"
}'

Finally, to see if a given deployment matches this version of the Compound Protocol, you can run token:match with a token address and token config:

npx saddle -n rinkeby script token:match 0x19B674715cD20626415C738400FDd0d32D6809B6 '{
  "underlying": "0x577D296678535e4903D59A4C929B718e1D575e0A",
  "comptroller": "$Comptroller",
  "interestRateModel": "$Base200bps_Slope3000bps",
  "initialExchangeRateMantissa": "2.0e18",
  "name": "Compound Kyber Network Crystal",
  "symbol": "cKNC",
  "decimals": "8",
  "admin": "$Timelock"
}'

Deploying a CToken from Docker Build

---

To deploy a specific version of the Compound Protocol, you can use the token:deploy script through Docker:

docker run --env ETHERSCAN_API_KEY --env VERIFY=true --env ACCOUNT=0x$(cat ~/.ethereum/rinkeby) compoundfinance/compound-protocol:latest npx saddle -n rinkeby script token:deploy '{
  "underlying": "0x577D296678535e4903D59A4C929B718e1D575e0A",
  "comptroller": "$Comptroller",
  "interestRateModel": "$Base200bps_Slope3000bps",
  "initialExchangeRateMantissa": "2.0e18",
  "name": "Compound Kyber Network Crystal",
  "symbol": "cKNC",
  "decimals": "8",
  "admin": "$Timelock"
}'

To match a deployed contract against a given version of the Compound Protocol, you can run token:match through Docker, passing a token address and config:

docker run --env ACCOUNT=0x$(cat ~/.ethereum/rinkeby) compoundfinance/compound-protocol:latest npx saddle -n rinkeby script token:match 0xF1BAd36CB247C82Cb4e9C2874374492Afb50d565 '{
  "underlying": "0x577D296678535e4903D59A4C929B718e1D575e0A",
  "comptroller": "$Comptroller",
  "interestRateModel": "$Base200bps_Slope3000bps",
  "initialExchangeRateMantissa": "2.0e18",
  "name": "Compound Kyber Network Crystal",
  "symbol": "cKNC",
  "decimals": "8",
  "admin": "$Timelock"
}'

Discussion

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

For security concerns, please email [email protected].

© Copyright 2020, Compound Labs