Proof of Liquidity Architecture 🌐

The above diagram gives an overview of how the main Proof of Liquidity (PoL) contracts interact with one another.

BeraChef.sol

The BeraChef contract is responsible for storing the preferences of validators for distributing $BGT emissions to reward vaults. A few key terms are important to understand in the BeraChef contract:

• CuttingBoard: Every validator has their own cutting board, which is used to store their preferences and weights for the reward vaults to which $BGT is distributed when selected to propose a block.
• FriendsOfTheChef: These are addresses that are eligible to receive weights from cutting boards. In other words, this is the set of whitelisted Reward vaults

Key Functions

queueNewCuttingBoard: This function allows validators to set a cutting board distribution for a future block. This is callable only by the validator.

activateQueuedCuttingBoard is called by the Distributor contract the next time the validator is selected to propose a block, activating it.

getActiveCuttingBoard/getQueuedCuttingBoard: These functions return the active/queued cutting board for a given validator.

updateFriendsOfTheChef: This function updates the status of whether a $BGT receiver/Reward Vault is whitelisted or not. This is callable only by the governance module, which is why a governance proposal is required to whitelist new Reward Vaults or make changes to existing ones.

Distributor.sol

The Distributor contract is responsible for distributing the block rewards from the reward controller. Each coinbase has its own cutting board, if it does not exist, a default cutting board is used. And if governance has not set the default cutting board, the rewards are not minted and distributed.

Key Functions

distributeFor: Is called for distributing $BGT rewards to the cutting board receivers of the given validator. The prover serves the purpose of proving that the given validator has indeed proposed a given block to the Distributor contract to correspondingly distribute rewards.

BerachainRewardsVault.sol

Colloquially known as Reward Vaults. Reward Vaults are contracts in which users can stake their Proof of Liquidity (PoL) eligible assets in order to receive $BGT rewards. Reward Vaults additionally store incentives provided by protocols to distribute to validators upon receiving $BGT.

Key Functions

addIncentive: This function allows the addition of a specified amount of an incentive token to be distributed at a specified rate per BGT emission. Incentive tokens must first be whitelisted by governance through whitelistIncentiveToken, defining a minimum incentive rate for that token.

stake: This function allows users to stake their PoL eligible assets in order to receive $BGT rewards.

withdraw: This function allows users to withdraw their staked assets from the Reward Vault.

BGT.sol

The BGT contract is responsible for handling all things related for $BGT and it is owned by the governance module. $BGT can be minted only by the BlockRewardController contract. A few key terms are important to understand in the BGT contract:

• boosts: $BGT holders can boost the rewards of validators, allowing them to direct more $BGT emissions for proposed blocks. Boosting is also referred to as "delegation". $BGT holders can apply their boosts to more than one validator.
• Sender whitelist: $BGT is non-transferrable and can only be sent by whitelisted addresses (such as the $BGT -> $BERA burner contract). This is to ensure that $BGT is only distributed to those who earn it through PoL.

Key Functions

queueBoost: This function allows $BGT holders to queue a boost for a validator. This is callable only by the $BGT holder.

activateBoost: This function brings into effect all of the queued and active boosts for a given validator. Updates to validators' boosts can be applied only after 8191 blocks have passed since the last update. This is to avoid aggressive redelegations.

BlockRewardController.sol

The main function of the BlockRewardController contract is to manage the reward rate for the Bera Governance Token ($BGT) and to handle the minting and distribution of $BGT rewards.

Key Functions

processRewards: This function handles the calculation and distribution of rewards for a given block. It calculates the rewards based on the base rate, reward rate, and any boosts provided by validators, then mints and distributes the calculated BGT tokens. This function is called by the Distributor contract.