Begin Block

At the start of every block the BeginBlock of the cdp module:

  • updates the status of the pricefeed for each collateral asset
  • If the pricefeed is active (reporting a price):
    • updates fees for CDPs
    • liquidates CDPs under the collateral ratio
  • nets out system debt and, if necessary, starts auctions to re-balance it
  • pays out the savings rate if sufficient time has past
  • records the last savings rate distribution, if one occurred

Update Fees

  • The total fees accumulated since the last block for each CDP are calculated.
  • If the fee amount is non-zero:
    • Set the updated value for fees
    • Set the fees updated time for the CDP to the current block time
    • An equal amount of debt coins are minted and sent to the system’s CDP module account.
    • An equal amount of stable asset coins are minted and sent to the system’s liquidator module account
    • Increment total principal.

Liquidate CDP

  • Get every cdp that is under the liquidation ratio for its collateral type.
  • For each cdp:
    • Remove all collateral and internal debt coins from cdp and deposits and delete it. Send the coins to the liquidator module account.
    • Start auctions of a fixed size from this collateral (with any remainder in a smaller sized auction), sending collateral and debt coins to the auction module account.
    • Decrement total principal.

Net Out System Debt, Re-Balance

  • Burn the maximum possible equal amount of debt and stable asset from the liquidator module account.
  • If there is enough debt remaining for an auction, start one.
  • If there is enough surplus stable asset, minus surplus reserved for the savings rate, remaining for an auction, start one.
  • Otherwise do nothing, leave debt/surplus to accumulate over subsequent blocks.

Distribute Surplus Stable Asset According to the Savings Rate

  • If SavingsDistributionFrequency seconds have elapsed since the previous distribution, the savings rate is applied to all accounts that hold stable asset.
  • Each account that holds stable asset is distributed a ratable portion of the surplus that is apportioned to the savings rate.
  • If distribution occurred, the time of the distribution is recorded.