alsco77 / canya-contracts-price-oracle

Reusable price oracle for ERC20 tokens listed on Bancor

What

• Trustless on chain token price Oracle (for any ERC20 token on the Bancor network)
• Utilises the arbitraged service provided by Bancor
• Simulates BancorConversion containing US$50k in the token liquidity and US$150k in BNT-DAI liquidity
• Check out the CAN -> DAI conversion on Ropsten
• Deployable and testable on testnet via truffle migration

How

• npm install -g truffle
• Modify settings in 2_converter_migration.js to your ERC20 values:

   var myTokenName = 'CanYaCoin';
   var myTokenSymbol = 'CAN';
   var myTokenDecimals = '6';

   var myTokenPriceUsd = 0.04;

   var BNTPriceUsd = 1.6;

• npm install -g ganache-cli
• ganache-cli
• truffle migrate --network ganache
• Congrats! You deployed an oracle

Deploying to Ropsten

• ensure you have followed the first 2 steps above
• Fill in your details on environment.sh and run the script (./environment.sh)
• npm install truffle-hdwallet-provider
• truffle migrate --network ropsten

Deploying a copy to mainnet

• Either choose to use a currently deployed and maintained version of the OracleBase contract or add these lines to your truffle migration:
• await deployer.deploy(ERC20BancorPriceOracleBase, <BNTToken>.address, <DAIToken>.address, <DAIBNTConverter>.address) <- deploy base oracle (DAI -> BNT conversion)
• await deployer.deploy(ERC20BancorPriceOracle, <MyERC20Token>.address, <BancorToTokenConverter>.address, <ERC20BancorPriceOracleBase>.address) <- ERC20->DAI oracle
• Use the address of this price oracle to interact with the contract from a custom contract

Post migration

Interacting with the oracle

• Load up Remix (http://remix.ethereum.org) and create/compile a file with the code from ERC20BancorPriceOracle.sol
• Choose environment Web3 Provider on Remix and set it to localhost:8545 (ganache-cli)
• Grab the deployed ERC20BancorPriceOracle address from the migration output
• Deploy an instance of the contract at this address
• Get the value of your token (including decimals) by hitting getDaiToToken(1000000000000000000)

Use it in your contract

• xxx

Testnet migration

Debug migration info

• Load up Remix (http://remix.ethereum.org) and create/compile a file with the BancorConverter.sol

• Choose environment Web3 Provider on Remix and set it to localhost:8545 (ganache-cli)

• BNT -> ERC20

  • Grab the deployed BancorToTokenConverter address from the migration output, head to Remix and connect to an instance of BancorConverter at that address
  • Interact with the getReturn function with the following parameters
    • _fromToken (BNT token address) -> execute connectorTokens(0) on the deployed contract
    • _toToken (MyERC20 token address) -> execute connectorTokens(1) on the deployed contract
    • _amount -> 1000000000000000000 (1 * 10**[BNT Decimals])
  • Return value should be (1/myTokenRatioToBNT) * (10**myTokenDecimals)

• DAI -> BNT

  • Grab the deployed DAIBNTConverter address from the migration output, head to Remix and connect to an instance of BancorConverter at that address
  • Interact with the getReturn function with the following parameters
    • _fromToken (DAI token address) -> execute connectorTokens(1) on the deployed contract
    • _toToken (BNT token address) -> execute connectorTokens(0) on the deployed contract
    • _amount -> 1000000000000000000 (1 * 10**[DAI Decimals])
  • Return value should be (1/currentBNTDAIRatio) * (10**18)

• To do a DAI -> ERC20 calculation, grab the output from DAI -> BNT and use it as the amount in BNT -> ERC20 15.624599

Note

• Had to create multiple ERC20 contracts with different names in order to play nice with the truffle migration script