Staker

Staker is a flexible, configurable staking contract. Staker makes it easy to distribute onchain staking rewards for any ERC20 token.

How it works:

1. Deploy and configurate a Staker

• Staker is deployed with a single staking token
• Staker is deployed with an admin, such as a DAO.
• Staker is configured to distribute one or more reward tokens

2. Tokenholders stake

• Tokenholders of the staking token can deposit those tokens in Staker.
• There is no delay to deposit or withdraw.
• If the staking token is a governance token, depositors can delegate their staked tokens' voting power to themselves or someone else
• The depositor sets a claimer who can claim the staking rewards, such as themselves or someone else.

3. Staker distributes rewards

• The admin sends rewards into Staker.
• Optionally, the admin sets eligibility criteria for rewards.
• Staker distributes those rewards over time.
• Each tokenholder's reward is proportional to their staked balance over time.
• Claimers can claim their accrued rewards at any time.

When Staker is used for a protocol or DAO, the rewards are generally funded by protocol revenue and/or issuance of the native token from the treasury.

Implementation details:

Staker can be deployed as an immutable contract with minimal governance. It does have some admin functions:

• Adding a new source of rewards
• Changing the eligibility oracle or the emergency pause guardian
• Overriding eligibility for a particular address

The staking token can be an ERC20 token, including ERC20Votes governance tokens. Staker splits up all voting power in Staker by creating a surrogate contract for each delegate.

Staker distributes rewards over a fixed period of time. That gives everyone a chance to stake and minimizes discontinuities from flash staking.

Staking system

The staking system accepts user stake, delegates their voting power, and distributes rewards for eligibile stakers.

stateDiagram-v2
    direction TB

    User --> CUF: Stakes tokens

    state Staker {
        state "Key User Functions" as CUF {
            stake --> claimReward
            claimReward --> withdraw
        }

        state "Key State" as KS {
            rewardRate
            deposits
        }

        state "Admin Functions" as CAF {
            setRewardNotifier
            setEarningPowerCalculator
        }
    }

    state DelegationSurrogate {
        state "Per Delegatee" as PD {
            HoldsTokens
            DelegatesVotes
        }
    }

    KS  --> DelegationSurrogate: Holds tokens per delegatee
    DelegationSurrogate --> Delegatee: Delegates voting power
    Admin --> CAF: e.g. governance

    RewardNotifier --> Staker: Tells Staker about new rewards
    EarningPowerCalculator --> Staker: Calculates eligibility

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Earning Power Calculator

The earning power calculator determines which stakers are eligible for a reward. This implementation uses an oracle. An oracle is needed because eligibility depends on off-chain behavior.

stateDiagram-v2
    direction TB

    state EarningPowerCalculator {
        state "Public Functions" as PF {
            GetEarningPower: getEarningPower()
        }

        state "Score Oracle Functions" as SOF {
            UpdateScore: updateDelegateeScore()
        }

        state "Owner Functions" as OF {
            OverrideScore: overrideDelegateeScore()
            SetScoreLock: setDelegateeScoreLock()
            SetGuardian: setOraclePauseGuardian()
        }

        state "Guardian Functions" as GF {
            SetOracleState: setOracleState()
        }


    }

    ScoreOracle --> SOF: Updates scores
    Owner --> OF: Admin controls
    Guardian --> GF: Emergency pause
    PF --> Staker: Returns earning power to staking system

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Development

These contracts were built and tested with care by the team at ScopeLift.

Build and test

This project uses Foundry. Follow these instructions to install it.

Clone the repo.

Set up your .env file

cp .env.template .env
# edit the .env to fill in values

Install dependencies & run tests.

forge install
forge build
forge test

Spec and lint

This project uses scopelint for linting and spec generation. Follow these instructions to install it.

To use scopelint's linting functionality, run:

scopelint check # check formatting
scopelint fmt # apply formatting changes

To use scopelint's spec generation functionality, run:

scopelint spec

This command will use the names of the contract's unit tests to generate a human readable spec. It will list each contract, its constituent functions, and the human readable description of functionality each unit test aims to assert.

License

The code in this repository is licensed under the GNU Affero General Public License unless otherwise indicated.

Copyright (C) 2024 Tally