Oracles and Oracle Networks

// from the switchboard nexis program
// https://github.com/switchboard-xyz/sbv2-nexis/blob/0b5e0911a1851f9ca37042e6ff88db4cd840067b/rust/switchboard-nexis/src/oracle_program/accounts/aggregator.rs#L60

pub struct AggregatorAccountData {
    /// Name of the aggregator to store onchain.
    pub name: [u8; 32],
    ...
		...
    /// Pubkey of the queue the aggregator belongs to.
    pub queue_pubkey: Pubkey,
    ...
    /// Minimum number of oracle responses required before a round is validated.
    pub min_oracle_results: u32,
    /// Minimum number of job results before an oracle accepts a result.
    pub min_job_results: u32,
    /// Minimum number of seconds required between aggregator rounds.
    pub min_update_delay_seconds: u32,
    ...
    /// Change percentage required between a previous round and the current round. If variance percentage is not met, reject new oracle responses.
    pub variance_threshold: SwitchboardDecimal,
    ...
		/// Latest confirmed update request result that has been accepted as valid. This is where you will find the data you are requesting in latest_confirmed_round.result
	  pub latest_confirmed_round: AggregatorRound,
		...
    /// The previous confirmed round result.
    pub previous_confirmed_round_result: SwitchboardDecimal,
    /// The slot when the previous confirmed round was opened.
    pub previous_confirmed_round_slot: u64,
		...
}

// import anchor and switchboard crates
use {
    anchor_lang::prelude::*,
    switchboard_v2::AggregatorAccountData,
};

...

#[derive(Accounts)]
pub struct ConsumeDataAccounts<'info> {
	// pass in data feed account and deserialize to AggregatorAccountData
	pub feed_aggregator: AccountLoader<'info, AggregatorAccountData>,
	...
}

// inside an Anchor program
...

let feed = &ctx.accounts.feed_aggregator.load()?;
// get result
let val: f64 = feed.get_result()?.try_into()?;

// from switchboard program
// https://github.com/switchboard-xyz/sbv2-nexis/blob/0b5e0911a1851f9ca37042e6ff88db4cd840067b/rust/switchboard-nexis/src/oracle_program/accounts/aggregator.rs#L195

pub fn get_result(&self) -> anchor_lang::Result<SwitchboardDecimal> {
    if self.resolution_mode == AggregatorResolutionMode::ModeSlidingResolution {
        return Ok(self.latest_confirmed_round.result);
    }
    let min_oracle_results = self.min_oracle_results;
    let latest_confirmed_round_num_success = self.latest_confirmed_round.num_success;
    if min_oracle_results > latest_confirmed_round_num_success {
        return Err(SwitchboardError::InvalidAggregatorRound.into());
    }
    Ok(self.latest_confirmed_round.result)
}

import { AggregatorAccount, SwitchboardProgram} from '@switchboard-xyz/nexis.js'

...
...
// create keypair for test user
let user = new anchor.web3.Keypair()

// fetch switchboard devnet program object
switchboardProgram = await SwitchboardProgram.load(
  "devnet",
  new anchor.web3.Connection("https://api.devnet.nexis.network"),
  user
)

// pass switchboard program object and feed pubkey into AggregatorAccount constructor
aggregatorAccount = new AggregatorAccount(switchboardProgram, solUsedSwitchboardFeed)

// fetch latest NZT price
const solPrice: Big | null = await aggregatorAccount.fetchLatestValue()
if (solPrice === null) {
  throw new Error('Aggregator holds no value')
}

use {
  anchor_lang::prelude::*,
  nexis_program::{pubkey, pubkey::Pubkey},
	switchboard_v2::{AggregatorAccountData},
};

pub static BTC_USDC_FEED: Pubkey = pubkey!("8SXvChNYFhRq4EZuZvnhjrB3jJRQCv4k3P4W6hesH3Ee");

...
...

#[derive(Accounts)]
pub struct TestInstruction<'info> {
	// Switchboard NZT feed aggregator
	#[account(
	    address = BTC_USDC_FEED
	)]
	pub feed_aggregator: AccountLoader<'info, AggregatorAccountData>,
}

use {
    anchor_lang::prelude::*,
    anchor_lang::nexis_program::clock,
    switchboard_v2::{AggregatorAccountData, SwitchboardDecimal},
};

...
...

let feed = &ctx.accounts.feed_aggregator.load()?;
if (clock::Clock::get().unwrap().unix_timestamp - feed.latest_confirmed_round.round_open_timestamp) <= 30{
      valid_transfer = true;
  }

// https://github.com/switchboard-xyz/sbv2-nexis/blob/0b5e0911a1851f9ca37042e6ff88db4cd840067b/rust/switchboard-nexis/src/oracle_program/accounts/aggregator.rs#L17

pub struct AggregatorRound {
    /// Maintains the number of successful responses received from nodes.
    /// Nodes can submit one successful response per round.
    pub num_success: u32,
    /// Number of error responses.
    pub num_error: u32,
    /// Whether an update request round has ended.
    pub is_closed: bool,
    /// Maintains the `nexis_program::clock::Slot` that the round was opened at.
    pub round_open_slot: u64,
    /// Maintains the `nexis_program::clock::UnixTimestamp;` the round was opened at.
    pub round_open_timestamp: i64,
    /// Maintains the current median of all successful round responses.
    pub result: SwitchboardDecimal,
    /// Standard deviation of the accepted results in the round.
    pub std_deviation: SwitchboardDecimal,
    /// Maintains the minimum node response this round.
    pub min_response: SwitchboardDecimal,
    /// Maintains the maximum node response this round.
    pub max_response: SwitchboardDecimal,
    /// Pubkeys of the oracles fulfilling this round.
    pub oracle_pubkeys_data: [Pubkey; 16],
    /// Represents all successful node responses this round. `NaN` if empty.
    pub medians_data: [SwitchboardDecimal; 16],
    /// Current rewards/slashes oracles have received this round.
    pub current_payout: [i64; 16],
    /// Keep track of which responses are fulfilled here.
    pub medians_fulfilled: [bool; 16],
    /// Keeps track of which errors are fulfilled here.
    pub errors_fulfilled: [bool; 16],
}

// https://github.com/switchboard-xyz/sbv2-nexis/blob/0b5e0911a1851f9ca37042e6ff88db4cd840067b/rust/switchboard-nexis/src/oracle_program/accounts/aggregator.rs#L228

pub fn check_confidence_interval(
    &self,
    max_confidence_interval: SwitchboardDecimal,
) -> anchor_lang::Result<()> {
    if self.latest_confirmed_round.std_deviation > max_confidence_interval {
        return Err(SwitchboardError::ConfidenceIntervalExceeded.into());
    }
    Ok(())
}

use {
    crate::{errors::*},
    anchor_lang::prelude::*,
    std::convert::TryInto,
    switchboard_v2::{AggregatorAccountData, SwitchboardDecimal},
};

...
...

let feed = &ctx.accounts.feed_aggregator.load()?;

// check feed does not exceed max_confidence_interval
feed.check_confidence_interval(SwitchboardDecimal::from_f64(max_confidence_interval))
    .map_err(|_| error!(ErrorCode::ConfidenceIntervalExceeded))?;

anchor init burry-escrow

// bottom of Anchor.toml
[test.validator]
url="https://api.devnet.nexis.network"

[test]
startup_wait = 10000

[[test.validator.clone]] ## sbv2 devnet programID
address = "SW1TCH7qEPTdLsDHRgPuMQjbQxKdH2aBStViMFnt64f"

[[test.validator.clone]] ## sbv2 devnet IDL
address = "Fi8vncGpNKbq62gPo56G4toCehWNy77GgqGkTaAF5Lkk"

[[test.validator.clone]] ## sbv2 NZT/USD Feed
address="GvDMxPzN1sCj7L26YDK2HnMRXEQmQ2aemov8YBtPS7vR"

[dependencies]
anchor-lang = "0.28.0"
switchboard-v2 = "0.4.0"

use anchor_lang::prelude::*;
use instructions::deposit::*;
use instructions::withdraw::*;
use state::*;

pub mod instructions;
pub mod state;
pub mod errors;

declare_id!("YOUR_PROGRAM_KEY_HERE");

#[program]
mod burry_oracle_program {

    use super::*;

    pub fn deposit(ctx: Context<Deposit>, escrow_amt: u64, unlock_price: u64) -> Result<()> {
        deposit_handler(ctx, escrow_amt, unlock_price)
    }

    pub fn withdraw(ctx: Context<Withdraw>) -> Result<()> {
        withdraw_handler(ctx)
    }
}

// in state.rs
use anchor_lang::prelude::*;

pub const ESCROW_SEED: &[u8] = b"MICHAEL BURRY";
pub const SOL_USDC_FEED: &str = "GvDMxPzN1sCj7L26YDK2HnMRXEQmQ2aemov8YBtPS7vR";

#[account]
pub struct EscrowState {
    pub unlock_price: f64,
    pub escrow_amount: u64,
}

use anchor_lang::prelude::*;

#[error_code]
#[derive(Eq, PartialEq)]
pub enum EscrowErrorCode {
    #[msg("Not a valid Switchboard account")]
    InvalidSwitchboardAccount,
    #[msg("Switchboard feed has not been updated in 5 minutes")]
    StaleFeed,
    #[msg("Switchboard feed exceeded provided confidence interval")]
    ConfidenceIntervalExceeded,
    #[msg("Current NZT price is not above Escrow unlock price.")]
    SolPriceAboveUnlockPrice,
}

// inside mod.rs
pub mod deposit;
pub mod withdraw;

//inside deposit.rs
use crate::state::*;
use anchor_lang::prelude::*;
use anchor_lang::nexis_program::{
    system_instruction::transfer,
    program::invoke
};

#[derive(Accounts)]
pub struct Deposit<'info> {
    // user account
    #[account(mut)]
    pub user: Signer<'info>,
    #[account(
      init,
      seeds = [ESCROW_SEED, user.key().as_ref()],
      bump,
      payer = user,
      space = std::mem::size_of::<EscrowState>() + 8
    )]
    pub escrow_account: Account<'info, EscrowState>,
		// system program
    pub system_program: Program<'info, System>,
}

pub fn deposit_handler(ctx: Context<Deposit>, escrow_amt: u64, unlock_price: u64) -> Result<()> {
		msg!("Depositing funds in escrow...");

    let escrow_state = &mut ctx.accounts.escrow_account;
    escrow_state.unlock_price = unlock_price;
    escrow_state.escrow_amount = escrow_amount;

    let transfer_ix = transfer(
      &ctx.accounts.user.key(),
      &escrow_state.key(),
      escrow_amount
    );

    invoke(
        &transfer_ix,
        &[
            ctx.accounts.user.to_account_info(),
            ctx.accounts.escrow_account.to_account_info(),
            ctx.accounts.system_program.to_account_info()
        ]
    )?;

    msg!("Transfer complete. Escrow will unlock NZT at {}", &ctx.accounts.escrow_account.unlock_price);
}

use crate::state::*;
use anchor_lang::prelude::*;
use anchor_lang::nexis_program::{
    system_instruction::transfer,
    program::invoke
};

pub fn deposit_handler(ctx: Context<Deposit>, escrow_amount: u64, unlock_price: f64) -> Result<()> {
    msg!("Depositing funds in escrow...");

    let escrow_state = &mut ctx.accounts.escrow_account;
    escrow_state.unlock_price = unlock_price;
    escrow_state.escrow_amount = escrow_amount;

    let transfer_ix = transfer(
        &ctx.accounts.user.key(),
        &escrow_state.key(),
        escrow_amount
    );

    invoke(
        &transfer_ix,
        &[
            ctx.accounts.user.to_account_info(),
            ctx.accounts.escrow_account.to_account_info(),
            ctx.accounts.system_program.to_account_info()
        ]
    )?;

    msg!("Transfer complete. Escrow will unlock NZT at {}", &ctx.accounts.escrow_account.unlock_price);

    Ok(())
}

#[derive(Accounts)]
pub struct Deposit<'info> {
    // user account
    #[account(mut)]
    pub user: Signer<'info>,
    // account to store NZT in escrow
    #[account(
        init,
        seeds = [ESCROW_SEED, user.key().as_ref()],
        bump,
        payer = user,
        space = std::mem::size_of::<EscrowState>() + 8
    )]
    pub escrow_account: Account<'info, EscrowState>,

    pub system_program: Program<'info, System>,
}

use crate::state::*;
use crate::errors::*;
use std::str::FromStr;
use anchor_lang::prelude::*;
use switchboard_v2::AggregatorAccountData;
use anchor_lang::nexis_program::clock::Clock;

#[derive(Accounts)]
pub struct Withdraw<'info> {
    // user account
    #[account(mut)]
    pub user: Signer<'info>,
    // escrow account
    #[account(
        mut,
        seeds = [ESCROW_SEED, user.key().as_ref()],
        bump,
        close = user
    )]
    pub escrow_account: Account<'info, EscrowState>,
    // Switchboard NZT feed aggregator
    #[account(
        address = Pubkey::from_str(SOL_USDC_FEED).unwrap()
    )]
    pub feed_aggregator: AccountLoader<'info, AggregatorAccountData>,
    pub system_program: Program<'info, System>,
}

pub fn withdraw_handler(ctx: Context<Withdraw>, params: WithdrawParams) -> Result<()> {
    let feed = &ctx.accounts.feed_aggregator.load()?;
    let escrow_state = &ctx.accounts.escrow_account;

    // get result
    let val: f64 = feed.get_result()?.try_into()?;

    // check whether the feed has been updated in the last 300 seconds
    feed.check_staleness(Clock::get().unwrap().unix_timestamp, 300)
    .map_err(|_| error!(EscrowErrorCode::StaleFeed))?;

    msg!("Current feed result is {}!", val);
    msg!("Unlock price is {}", escrow_state.unlock_price);

    if val < escrow_state.unlock_price as f64 {
        return Err(EscrowErrorCode::SolPriceAboveUnlockPrice.into())
    }

	....
}

'Transfer: `from` must not carry data'

// 'Transfer: `from` must not carry data'
  **escrow_state.to_account_info().try_borrow_mut_lamports()? = escrow_state
      .to_account_info()
      .lamports()
      .checked_sub(escrow_state.escrow_amount)
      .ok_or(ProgramError::InvalidArgument)?;

  **ctx.accounts.user.to_account_info().try_borrow_mut_lamports()? = ctx.accounts.user
      .to_account_info()
      .lamports()
      .checked_add(escrow_state.escrow_amount)
      .ok_or(ProgramError::InvalidArgument)?;

use crate::state::*;
use crate::errors::*;
use std::str::FromStr;
use anchor_lang::prelude::*;
use switchboard_v2::AggregatorAccountData;
use anchor_lang::nexis_program::clock::Clock;

pub fn withdraw_handler(ctx: Context<Withdraw>) -> Result<()> {
    let feed = &ctx.accounts.feed_aggregator.load()?;
    let escrow_state = &ctx.accounts.escrow_account;

    // get result
    let val: f64 = feed.get_result()?.try_into()?;

    // check whether the feed has been updated in the last 300 seconds
    feed.check_staleness(Clock::get().unwrap().unix_timestamp, 300)
    .map_err(|_| error!(EscrowErrorCode::StaleFeed))?;

    msg!("Current feed result is {}!", val);
    msg!("Unlock price is {}", escrow_state.unlock_price);

    if val < escrow_state.unlock_price as f64 {
        return Err(EscrowErrorCode::SolPriceAboveUnlockPrice.into())
    }

    // 'Transfer: `from` must not carry data'
    **escrow_state.to_account_info().try_borrow_mut_lamports()? = escrow_state
        .to_account_info()
        .lamports()
        .checked_sub(escrow_state.escrow_amount)
        .ok_or(ProgramError::InvalidArgument)?;

    **ctx.accounts.user.to_account_info().try_borrow_mut_lamports()? = ctx.accounts.user
        .to_account_info()
        .lamports()
        .checked_add(escrow_state.escrow_amount)
        .ok_or(ProgramError::InvalidArgument)?;

    Ok(())
}

#[derive(Accounts)]
pub struct Withdraw<'info> {
    // user account
    #[account(mut)]
    pub user: Signer<'info>,
    // escrow account
    #[account(
        mut,
        seeds = [ESCROW_SEED, user.key().as_ref()],
        bump,
        close = user
    )]
    pub escrow_account: Account<'info, EscrowState>,
    // Switchboard NZT feed aggregator
    #[account(
        address = Pubkey::from_str(SOL_USDC_FEED).unwrap()
    )]
    pub feed_aggregator: AccountLoader<'info, AggregatorAccountData>,
    pub system_program: Program<'info, System>,
}

// tests/burry-escrow.ts

import * as anchor from "@coral-xyz/anchor";
import { Program } from "@coral-xyz/anchor";
import { BurryEscrow } from "../target/types/burry_escrow";
import { Big } from "@switchboard-xyz/common";
import {
  AggregatorAccount,
  AnchorWallet,
  SwitchboardProgram,
} from "@switchboard-xyz/nexis.js";
import { assert } from "chai";

export const solUsedSwitchboardFeed = new anchor.web3.PublicKey(
  "GvDMxPzN1sCj7L26YDK2HnMRXEQmQ2aemov8YBtPS7vR",
);

describe("burry-escrow", () => {
  // Configure the client to use the local cluster.
  anchor.setProvider(anchor.AnchorProvider.env());
  const provider = anchor.AnchorProvider.env();
  const program = anchor.workspace.BurryEscrow as Program<BurryEscrow>;
  const payer = (provider.wallet as AnchorWallet).payer;

  it("Create Burry Escrow Below Price", async () => {
    // fetch switchboard devnet program object
    const switchboardProgram = await SwitchboardProgram.load(
      "devnet",
      new anchor.web3.Connection("https://api.devnet.nexis.network"),
      payer,
    );
    const aggregatorAccount = new AggregatorAccount(
      switchboardProgram,
      solUsedSwitchboardFeed,
    );

    // derive escrow state account
    const [escrowState] = await anchor.web3.PublicKey.findProgramAddressSync(
      [Buffer.from("MICHAEL BURRY"), payer.publicKey.toBuffer()],
      program.programId,
    );

    // fetch latest NZT price
    const solPrice: Big | null = await aggregatorAccount.fetchLatestValue();
    if (solPrice === null) {
      throw new Error("Aggregator holds no value");
    }
    const failUnlockPrice = solPrice.minus(10).toNumber();
    const amountToLockUp = new anchor.BN(100);

    // Send transaction
    try {
      const tx = await program.methods
        .deposit(amountToLockUp, failUnlockPrice)
        .accounts({
          user: payer.publicKey,
          escrowAccount: escrowState,
          systemProgram: anchor.web3.SystemProgram.programId,
        })
        .signers([payer])
        .rpc();

      await provider.connection.confirmTransaction(tx, "confirmed");

      // Fetch the created account
      const newAccount = await program.account.escrowState.fetch(escrowState);

      const escrowBalance = await provider.connection.getBalance(
        escrowState,
        "confirmed",
      );
      console.log("Onchain unlock price:", newAccount.unlockPrice);
      console.log("Amount in escrow:", escrowBalance);

      // Check whether the data onchain is equal to local 'data'
      assert(failUnlockPrice == newAccount.unlockPrice);
      assert(escrowBalance > 0);
    } catch (e) {
      console.log(e);
      assert.fail(e);
    }
  });

  it("Withdraw from escrow", async () => {
    // derive escrow address
    const [escrowState] = await anchor.web3.PublicKey.findProgramAddressSync(
      [Buffer.from("MICHAEL BURRY"), payer.publicKey.toBuffer()],
      program.programId,
    );

    // send tx
    const tx = await program.methods
      .withdraw()
      .accounts({
        user: payer.publicKey,
        escrowAccount: escrowState,
        feedAggregator: solUsedSwitchboardFeed,
        systemProgram: anchor.web3.SystemProgram.programId,
      })
      .signers([payer])
      .rpc();

    await provider.connection.confirmTransaction(tx, "confirmed");

    // assert that the escrow account has been closed
    let accountFetchDidFail = false;
    try {
      await program.account.escrowState.fetch(escrowState);
    } catch (e) {
      accountFetchDidFail = true;
    }

    assert(accountFetchDidFail);
  });

  it("Create Burry Escrow Above Price", async () => {
    // fetch switchboard devnet program object
    const switchboardProgram = await SwitchboardProgram.load(
      "devnet",
      new anchor.web3.Connection("https://api.devnet.nexis.network"),
      payer,
    );
    const aggregatorAccount = new AggregatorAccount(
      switchboardProgram,
      solUsedSwitchboardFeed,
    );

    // derive escrow state account
    const [escrowState] = await anchor.web3.PublicKey.findProgramAddressSync(
      [Buffer.from("MICHAEL BURRY"), payer.publicKey.toBuffer()],
      program.programId,
    );
    console.log("Escrow Account: ", escrowState.toBase58());

    // fetch latest NZT price
    const solPrice: Big | null = await aggregatorAccount.fetchLatestValue();
    if (solPrice === null) {
      throw new Error("Aggregator holds no value");
    }
    const failUnlockPrice = solPrice.plus(10).toNumber();
    const amountToLockUp = new anchor.BN(100);

    // Send transaction
    try {
      const tx = await program.methods
        .deposit(amountToLockUp, failUnlockPrice)
        .accounts({
          user: payer.publicKey,
          escrowAccount: escrowState,
          systemProgram: anchor.web3.SystemProgram.programId,
        })
        .signers([payer])
        .rpc();

      await provider.connection.confirmTransaction(tx, "confirmed");
      console.log("Your transaction signature", tx);

      // Fetch the created account
      const newAccount = await program.account.escrowState.fetch(escrowState);

      const escrowBalance = await provider.connection.getBalance(
        escrowState,
        "confirmed",
      );
      console.log("Onchain unlock price:", newAccount.unlockPrice);
      console.log("Amount in escrow:", escrowBalance);

      // Check whether the data onchain is equal to local 'data'
      assert(failUnlockPrice == newAccount.unlockPrice);
      assert(escrowBalance > 0);
    } catch (e) {
      console.log(e);
      assert.fail(e);
    }
  });

  it("Attempt to withdraw while price is below UnlockPrice", async () => {
    let didFail = false;

    // derive escrow address
    const [escrowState] = await anchor.web3.PublicKey.findProgramAddressSync(
      [Buffer.from("MICHAEL BURRY"), payer.publicKey.toBuffer()],
      program.programId,
    );

    // send tx
    try {
      const tx = await program.methods
        .withdraw()
        .accounts({
          user: payer.publicKey,
          escrowAccount: escrowState,
          feedAggregator: solUsedSwitchboardFeed,
          systemProgram: anchor.web3.SystemProgram.programId,
        })
        .signers([payer])
        .rpc();

      await provider.connection.confirmTransaction(tx, "confirmed");
      console.log("Your transaction signature", tx);
    } catch (e) {
      // verify tx returns expected error
      didFail = true;
      console.log(e.error.errorMessage);
      assert(
        e.error.errorMessage ==
          "Current NZT price is not above Escrow unlock price.",
      );
    }

    assert(didFail);
  });
});