Description

• STABLESPREAD default price feeds current rely on a known flaky CryptoWatch pair: "USTUSDT on Bittrex". For example, querying the endpoint https://api.cryptowat.ch/markets/uniswap-v2/ustusdt/ohlc returns the latest OHLC timestamp as 1610727300, which is 5 hours behind the current Unix timestamp 1610746046. We need a strategy to handle missing historical price data. Additionally, we need to provide a way for aggregator price feeds (i.e. Medianizer and BasketSpreadPriceFeed) to add more details about which dependent price feed is the offending one. One idea is to add a callback function that can be called by clients, such as the SyntheticPegMonitor and the Disputer, to try to fetch more information about the missing historical price error.
• When the liquidator purposefully decides not to liquidate a position because it is prior to the slow withdrawal's defenseActivationPercentage, the Liquidator should NOT emit an error-level log. Instead, the liquidator should display that it is purposefully ignoring this liquidation.
• Change disputer log about missing historical price to an error level log instead of a warning. This could cause the system to lose funds if the disputer cannot dispute because it is missing a historical price.
• Ability to override the level of the log when the monitor sees a liquidation.