Vega/UMA Oracles

Example contracts showcasing how UMA Optimistic Oracles can be used for Vega market termination and settlement

Installation

This example repository uses Foundry to build and execute Solidity scripts. Please see the Foundry Book for installation instructions:

https://book.getfoundry.sh/

Usage

Modify

Two sample oracles are included; TerminationOracle and SettlementOracle. Both work in similar fashion. When proposing a market on Vega, TerminationOracle could be used as an external oracle for dataSourceSpecForTradingTermination, while SettlementOracle could be used as an external oracle for dataSourceSpecForSettlementData.

Both contracts have a "trigger" function, respectively submitClaim. Calling this functios require the "asserter" to place a bond. This bond acts as an incentive in the UMA system for the asserter to act truthfully. In case of a dispute this bond could be lost, or if a dispute is overturned could grow. Most of the time, assertions are assumed not to be disputed, hence the "Optimistic" part. This bond must be paid in an UMA approved currency, and is defined by the bondCurrency and bondAmount on the contracts in this repository.

Upon placing an assertion (eg. to terminate) a claim is submitted to UMA, and can be seen in the Oracle dApp (https://oracle.uma.xyz/). Inside the contracts of this repository a struct is stored containing metadata about the assertion, and it's resolution.

Identifiers to look up the unique structs is itself a struct in the examples. This makes it possible to define them from more user friendly data such as a market name, a sequence number or any combination of fields.

Upon a final result from UMA, the contracts will get a callback when either the original asserter claims back their bond, or a disputer claims their reward, which will trigger an update on the stored data in the example contracts, and the result can be read via getData.

sample-proposal.json contains a partial Vega market proposal for contracts deployed on the Goerli network.

Small, selective ABIs can be generated with forge inspect and jq. Here the getTermination from TerminationOracle is filtered out and encoded as a JSON string in the format expected by Vega:

forge inspect TerminationOracle abi | jq '[.[] | select(.name == "getData")] | tostring' --monochrome-output --compact-output

Build

$ forge build

Test

$ forge test

Format

$ forge fmt

Deploy

Modify the included .env file, filling in missing variables. Here's an example for Goerli Testnet:

export CHAIN=goerli
export CHAIN_ID=5
export ETH_RPC_URL=https://goerli.infura.io/v3/XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
export ETHERSCAN_API_KEY=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

export WETH_ADDRESS=0xB4FBF271143F4FBf7B91A5ded31805e42b2208d6
export UMA_OPTIMISTIC_ORACLE_V3=0x9923D42eF695B5dd9911D05Ac944d4cAca3c4EAB

export PRIVATE_KEY=0xXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

The included Makefile has a phony deploy target that will wrap 1 Ether, deploy the two sample oracles and approve both to spend 0.5 WETH for bonds:

$ make deploy

License

MIT