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Synthetix Single Staking Farm

Web3 applications often incentivize holding tokens through yield farming. A Single Staking Farm is a smart contract that allows a user to deposit a single token and accumulate rewards over time. These rewards are claimable through the same smart contract interface.

A very simple staking contract is the Synthetix StakingRewards smart contract. A user can deposit a single token, and can earn another token emitted over a period of time.

Using the SingleStakingFarmContractPositionHelper​

The SingleStakingFarmContractPositionHelper helper class can be used to build a list of ContractPosition objects for a farm contract position group. In this example, we'll look at Synthetix LP token staking.

Synthetix allows holders of synth tokens or LP tokens of synth tokens to stake their tokens in return for SNX rewards. Although the rewards for these farms are over, we will integrate these for educational purposes.

First, let's generate a new contract position fetcher with yarn studio create-contract-position-fetcher synthetix. When prompted for a group, select Create New, then enter farm as the ID and Farms as the label. When prompted for a network, select ethereum.

Let's now open up our newly generator boilerplate in src/apps/synthetix/ethereum/synthetix.farm.contract-position-fetcher.ts:

import { Inject } from '@nestjs/common';

import { IAppToolkit, APP_TOOLKIT } from '~app-toolkit/app-toolkit.interface';
import { Register } from '~app-toolkit/decorators';
import { PositionFetcher } from '~position/position-fetcher.interface';
import { ContractPosition } from '~position/position.interface';
import { Network } from '~types/network.interface';

import { SynthetixContractFactory } from '../contracts';
import { SYNTHETIX_DEFINITION } from '../synthetix.definition';

const appId = SYNTHETIX_DEFINITION.id;
const groupId = SYNTHETIX_DEFINITION.groups.farm.id;
const network = Network.ETHEREUM_MAINNET;

@Register.ContractPositionFetcher({ appId, groupId, network })
export class EthereumSynthetixFarmContractPositionFetcher implements PositionFetcher<ContractPosition> {
  constructor(
    @Inject(APP_TOOLKIT) private readonly appToolkit: IAppToolkit,
    @Inject(SynthetixContractFactory) private readonly synthetixContractFactory: SynthetixContractFactory,
  ) {}

  async getPositions() {
    return [];
  }
}

Reference the helper class through the AppToolkit​

We'll use the SingleStakingFarmContractPositionHelper helper class registered in our AppToolkit to quickly build the farm contract positions. We'll call the getPositions method on this helper class, and pass in the generated Ethers contract interface for the StakingRewards contract.

@Register.ContractPositionFetcher({ appId, groupId, network })
export class EthereumSynthetixFarmContractPositionFetcher implements PositionFetcher<ContractPosition> {
  constructor(
    @Inject(APP_TOOLKIT) private readonly appToolkit: IAppToolkit,
    @Inject(SynthetixContractFactory) private readonly synthetixContractFactory: SynthetixContractFactory,
  ) {}

  async getPositions() {
    return this.appToolkit.helpers.singleStakingFarmContractPositionHelper.getContractPositions<SynthetixStakingRewards>({
      // ...
    });
  }
}

Add appId, groupId, and network parameters​

We'll specify our appId, groupId, and network identifiers. These should match the values specified in the @Register.ContractPositionFetcher decorator.

@Register.ContractPositionFetcher({ appId, groupId, network })
export class EthereumSynthetixFarmContractPositionFetcher implements PositionFetcher<ContractPosition> {
  constructor(
    @Inject(APP_TOOLKIT) private readonly appToolkit: IAppToolkit,
    @Inject(SynthetixContractFactory) private readonly synthetixContractFactory: SynthetixContractFactory,
  ) {}

  async getPositions() {
    return this.appToolkit.helpers.singleStakingFarmContractPositionHelper.getContractPositions<SynthetixStakingRewards>({
      network: Network.ETHEREUM_MAINNET,
      appId: SYNTHETIX_DEFINITION.id,
      groupId: SYNTHETIX_DEFINITION.groups.farm.id,
      // ...
    });
  }
}

Add dependencies parameter​

We'll use the dependencies parameter to specify which token groups are required as dependencies for building this set of farm contract positions. In the case of Synthetix, users can deposit their Synthetix synth positions in Balancer V1 and Curve, so we'll reference these two app groups in the dependencies array.

@Register.ContractPositionFetcher({ appId, groupId, network })
export class EthereumSynthetixFarmContractPositionFetcher implements PositionFetcher<ContractPosition> {
  constructor(
    @Inject(APP_TOOLKIT) private readonly appToolkit: IAppToolkit,
    @Inject(SynthetixContractFactory) private readonly synthetixContractFactory: SynthetixContractFactory,
  ) {}

  async getPositions() {
    return this.appToolkit.helpers.singleStakingFarmContractPositionHelper.getContractPositions<SynthetixStakingRewards>({
      network: Network.ETHEREUM_MAINNET,
      appId: SYNTHETIX_DEFINITION.id,
      groupId: SYNTHETIX_DEFINITION.groups.farm.id,
      dependencies: [
        { appId: BALANCER_V1_DEFINITION.id, groupIds: [BALANCER_V1_DEFINITION.groups.pool.id], network: Network.ETHEREUM_MAINNET },
        { appId: CURVE_DEFINITION.id, groupIds: [CURVE_DEFINITION.groups.pool.id], network: Network.ETHEREUM_MAINNET },
      ],
      // ...
    });
  }
}

Define your farm definitions​

We'll simply define our farms statically in this case. We'll need to know the contract address of the farm, and the addresses for the staked and reward tokens. Let's define these as follows:

const FARMS = [
  // iBTC
  {
    address: '0x167009dcda2e49930a71712d956f02cc980dcc1b',
    stakedTokenAddress: '0xd6014ea05bde904448b743833ddf07c3c7837481',
    rewardTokenAddresses: ['0xc011a73ee8576fb46f5e1c5751ca3b9fe0af2a6f'],
  },
  // iETH
  {
    address: '0x6d4f135af7dfcd4bdf6dcb9d7911f5d243872a52',
    stakedTokenAddress: '0xa9859874e1743a32409f75bb11549892138bba1e',
    rewardTokenAddresses: ['0xc011a73ee8576fb46f5e1c5751ca3b9fe0af2a6f'],
  },
  // iETH
  {
    address: '0x3f27c540adae3a9e8c875c61e3b970b559d7f65d',
    stakedTokenAddress: '0xa9859874e1743a32409f75bb11549892138bba1e',
    rewardTokenAddresses: ['0xc011a73ee8576fb46f5e1c5751ca3b9fe0af2a6f'],
  },
  // BPT sUSD / sTSLA
  {
    address: '0xf0de877f2f9e7a60767f9ba662f10751566ad01c',
    stakedTokenAddress: '0x055db9aff4311788264798356bbf3a733ae181c6', // sTSLA
    rewardTokenAddresses: ['0xc011a73ee8576fb46f5e1c5751ca3b9fe0af2a6f'],
  },
  // CRV EURS / sEUR
  {
    address: '0xc0d8994cd78ee1980885df1a0c5470fc977b5cfe',
    stakedTokenAddress: '0x194ebd173f6cdace046c53eacce9b953f28411d1',
    rewardTokenAddresses: ['0xc011a73ee8576fb46f5e1c5751ca3b9fe0af2a6f'],
  },
];

Add resolveFarmDefinitions parameter​

We'll use the resolveFarmDefinitions factory method to specify the definitions as described in the previous section. We could also have used resolveFarmAddresses, and dynamically resolve the addresses of the staked token address and the reward token addresses, but since we know these values are static, we can simply hardcode these in our position fetcher.

@Register.ContractPositionFetcher({ appId, groupId, network })
export class EthereumSynthetixFarmContractPositionFetcher implements PositionFetcher<ContractPosition> {
  constructor(
    @Inject(APP_TOOLKIT) private readonly appToolkit: IAppToolkit,
    @Inject(SynthetixContractFactory) private readonly synthetixContractFactory: SynthetixContractFactory,
  ) {}

  async getPositions() {
    return this.appToolkit.helpers.singleStakingFarmContractPositionHelper.getContractPositions<SynthetixStakingRewards>({
      network: Network.ETHEREUM_MAINNET,
      appId: SYNTHETIX_DEFINITION.id,
      groupId: SYNTHETIX_DEFINITION.groups.farm.id,
      dependencies: [
        { appId: BALANCER_V1_DEFINITION.id, groupIds: [BALANCER_V1_DEFINITION.groups.pool.id], network: Network.ETHEREUM_MAINNET },
        { appId: CURVE_DEFINITION.id, groupIds: [CURVE_DEFINITION.groups.pool.id], network: Network.ETHEREUM_MAINNET },
      ],
      resolveFarmDefinitions: async () => FARMS,
      // ...
    });
  }
}

Add resolveFarmContract parameter​

We'll use the resolveFarmContract method as a factory that returns an instance of the SynthetixStakingRewards contract for a given address and network.

@Register.ContractPositionFetcher({ appId, groupId, network })
export class EthereumSynthetixFarmContractPositionFetcher implements PositionFetcher<ContractPosition> {
  constructor(
    @Inject(APP_TOOLKIT) private readonly appToolkit: IAppToolkit,
    @Inject(SynthetixContractFactory) private readonly synthetixContractFactory: SynthetixContractFactory,
  ) {}

  async getPositions() {
    return this.appToolkit.helpers.singleStakingFarmContractPositionHelper.getContractPositions<SynthetixStakingRewards>({
      network: Network.ETHEREUM_MAINNET,
      appId: SYNTHETIX_DEFINITION.id,
      groupId: SYNTHETIX_DEFINITION.groups.farm.id,
      dependencies: [
        { appId: BALANCER_V1_DEFINITION.id, groupIds: [BALANCER_V1_DEFINITION.groups.pool.id], network: Network.ETHEREUM_MAINNET },
        { appId: CURVE_DEFINITION.id, groupIds: [CURVE_DEFINITION.groups.pool.id], network: Network.ETHEREUM_MAINNET },
      ],
      resolveFarmDefinitions: async () => FARMS,
      resolveFarmContract: ({ network, address }) => this.synthetixContractFactory.synthetixStakingRewards({ network, address }),
      // ...
    });
  }
}

Add resolveIsActive parameter​

We'll use the resolveIsActive method to resolve if the farm is active, that is, if the farm is still emitting rewards to users with staked tokens. In the case of Synthetix StakingRewards contracts, there's a periodFinish method that returns the timestamp at which rewards are over.

We can use the SynthetixSingleStakingIsActiveStrategy helper class to build a method that will check this value against the current time and determine if the farm is active or not.

@Register.ContractPositionFetcher({ appId, groupId, network })
export class EthereumCurveFarmContractPositionFetcher implements PositionFetcher<ContractPosition> {
  async getPositions() {
    return this.appToolkit.helpers.singleStakingFarmContractPositionHelper.getContractPositions<SynthetixStakingRewards>({
      network: Network.ETHEREUM_MAINNET,
      appId: SYNTHETIX_DEFINITION.id,
      groupId: SYNTHETIX_DEFINITION.groups.farm.id,
      dependencies: [
        { appId: BALANCER_V1_DEFINITION.id, groupIds: [BALANCER_V1_DEFINITION.groups.pool.id], network: Network.ETHEREUM_MAINNET },
        { appId: CURVE_DEFINITION.id, groupIds: [CURVE_DEFINITION.groups.pool.id], network: Network.ETHEREUM_MAINNET },
      ],
      resolveFarmDefinitions: async () => FARMS,
      resolveFarmContract: ({ network, address }) => this.synthetixContractFactory.synthetixStakingRewards({ network, address }),
      resolveIsActive: this.synthetixSingleStakingIsActiveStrategy.build({
        resolvePeriodFinish: ({ contract, multicall }) => multicall.wrap(contract).periodFinish(),
      }),
      // ...
    });
  }
}

Add resolveRois parameter​

We'll use the resolveRois method to resolve the return on investment as a percentage of the total staked value. The Synthetix StakingReward contracts expose a rewardRate method which specifies the amount of reward token emitted per second.

We can use the SynthetixSingleStakingRoiStrategy helper class to build a method that will calculate the return on investment as a percentage relative to the staked amount.

@Register.ContractPositionFetcher({ appId, groupId, network })
export class EthereumCurveFarmContractPositionFetcher implements PositionFetcher<ContractPosition> {
  async getPositions() {
    return this.appToolkit.helpers.singleStakingFarmContractPositionHelper.getContractPositions<SynthetixStakingRewards>({
      network: Network.ETHEREUM_MAINNET,
      appId: SYNTHETIX_DEFINITION.id,
      groupId: SYNTHETIX_DEFINITION.groups.farm.id,
      dependencies: [
        { appId: BALANCER_V1_DEFINITION.id, groupIds: [BALANCER_V1_DEFINITION.groups.pool.id], network: Network.ETHEREUM_MAINNET },
        { appId: CURVE_DEFINITION.id, groupIds: [CURVE_DEFINITION.groups.pool.id], network: Network.ETHEREUM_MAINNET },
      ],
      resolveFarmDefinitions: async () => FARMS,
      resolveFarmContract: ({ network, address }) => this.synthetixContractFactory.synthetixStakingRewards({ network, address }),
      resolveIsActive: this.synthetixSingleStakingIsActiveStrategy.build({
        resolvePeriodFinish: ({ contract, multicall }) => multicall.wrap(contract).periodFinish(),
      }),
      resolveRois: this.synthetixSingleStakingRoiStrategy.build({
        resolveRewardRates: ({ contract, multicall }) => multicall.wrap(contract).rewardRate(),
      }),
    });
  }
}

We're done!