sui_json_rpc/

governance_api.rs

// Copyright (c) Mysten Labs, Inc.
// SPDX-License-Identifier: Apache-2.0

use std::cmp::max;
use std::collections::BTreeMap;
use std::sync::Arc;

use async_trait::async_trait;
use cached::SizedCache;
use cached::proc_macro::cached;
use itertools::Itertools;
use jsonrpsee::RpcModule;
use jsonrpsee::core::RpcResult;
use tracing::{info, instrument};

use sui_core::authority::AuthorityState;
use sui_json_rpc_api::{GovernanceReadApiOpenRpc, GovernanceReadApiServer, JsonRpcMetrics};
use sui_json_rpc_types::{DelegatedStake, Stake, StakeStatus};
use sui_json_rpc_types::{SuiCommittee, ValidatorApy, ValidatorApys};
use sui_open_rpc::Module;
use sui_types::base_types::{ObjectID, SuiAddress};
use sui_types::committee::EpochId;
use sui_types::dynamic_field::get_dynamic_field_from_store;
use sui_types::error::{SuiError, SuiErrorKind, UserInputError};
use sui_types::governance::StakedSui;
use sui_types::id::ID;
use sui_types::object::ObjectRead;
use sui_types::sui_serde::BigInt;
use sui_types::sui_system_state::PoolTokenExchangeRate;
use sui_types::sui_system_state::SuiSystemStateTrait;
use sui_types::sui_system_state::sui_system_state_summary::SuiSystemStateSummary;
use sui_types::sui_system_state::{SuiSystemState, get_validator_from_table};

use crate::authority_state::StateRead;
use crate::error::{Error, RpcInterimResult, SuiRpcInputError};
use crate::{ObjectProvider, SuiRpcModule, with_tracing};

#[derive(Clone)]
pub struct GovernanceReadApi {
    state: Arc<dyn StateRead>,
    pub metrics: Arc<JsonRpcMetrics>,
}

impl GovernanceReadApi {
    pub fn new(state: Arc<AuthorityState>, metrics: Arc<JsonRpcMetrics>) -> Self {
        Self { state, metrics }
    }

    async fn get_staked_sui(&self, owner: SuiAddress) -> Result<Vec<StakedSui>, Error> {
        let state = self.state.clone();
        let result = state.get_staked_sui(owner).await?;

        self.metrics
            .get_stake_sui_result_size
            .observe(result.len() as f64);
        self.metrics
            .get_stake_sui_result_size_total
            .inc_by(result.len() as u64);
        Ok(result)
    }

    async fn get_stakes_by_ids(
        &self,
        staked_sui_ids: Vec<ObjectID>,
    ) -> Result<Vec<DelegatedStake>, Error> {
        let state = self.state.clone();
        let stakes_read: Vec<_> = staked_sui_ids
            .iter()
            .map(|id| state.get_object_read(id))
            .collect::<Result<Vec<_>, _>>()?;

        if stakes_read.is_empty() {
            return Ok(vec![]);
        }

        let mut stakes: Vec<(StakedSui, bool)> = vec![];
        for stake in stakes_read.into_iter() {
            match stake {
                ObjectRead::Exists(_, o, _) => stakes.push((StakedSui::try_from(&o)?, true)),
                ObjectRead::Deleted(oref) => {
                    match self
                        .state
                        .find_object_lt_or_eq_version(&oref.0, &oref.1.one_before().unwrap())
                        .await?
                    {
                        Some(o) => stakes.push((StakedSui::try_from(&o)?, false)),
                        None => Err(SuiRpcInputError::UserInputError(
                            UserInputError::ObjectNotFound {
                                object_id: oref.0,
                                version: None,
                            },
                        ))?,
                    }
                }
                ObjectRead::NotExists(id) => Err(SuiRpcInputError::UserInputError(
                    UserInputError::ObjectNotFound {
                        object_id: id,
                        version: None,
                    },
                ))?,
            }
        }

        self.get_delegated_stakes(stakes).await
    }

    async fn get_stakes(&self, owner: SuiAddress) -> Result<Vec<DelegatedStake>, Error> {
        let timer = self.metrics.get_stake_sui_latency.start_timer();
        let stakes = self.get_staked_sui(owner).await?;
        if stakes.is_empty() {
            return Ok(vec![]);
        }
        drop(timer);

        let _timer = self.metrics.get_delegated_sui_latency.start_timer();

        self.get_delegated_stakes(stakes.into_iter().map(|s| (s, true)).collect())
            .await
    }

    async fn get_delegated_stakes(
        &self,
        stakes: Vec<(StakedSui, bool)>,
    ) -> Result<Vec<DelegatedStake>, Error> {
        let pools = stakes.into_iter().fold(
            BTreeMap::<_, Vec<_>>::new(),
            |mut pools, (stake, exists)| {
                pools
                    .entry(stake.pool_id())
                    .or_default()
                    .push((stake, exists));
                pools
            },
        );

        let system_state = self.get_system_state()?;
        let system_state_summary: SuiSystemStateSummary =
            system_state.clone().into_sui_system_state_summary();

        let rates = exchange_rates(&self.state, system_state_summary.epoch)
            .await?
            .into_iter()
            .map(|rates| (rates.pool_id, rates))
            .collect::<BTreeMap<_, _>>();

        let mut delegated_stakes = vec![];
        for (pool_id, stakes) in pools {
            // Rate table and rate can be null when the pool is not active
            let rate_table = rates.get(&pool_id).ok_or_else(|| {
                SuiRpcInputError::GenericNotFound(
                    "Cannot find rates for staking pool {pool_id}".to_string(),
                )
            })?;
            let current_rate = rate_table.rates.first().map(|(_, rate)| rate);

            let mut delegations = vec![];
            for (stake, exists) in stakes {
                let status = if !exists {
                    StakeStatus::Unstaked
                } else if system_state_summary.epoch >= stake.activation_epoch() {
                    // TODO: use dev_inspect to call a move function to get the estimated reward
                    let estimated_reward = if let Some(current_rate) = current_rate {
                        let stake_rate = rate_table
                            .rates
                            .iter()
                            .find_map(|(epoch, rate)| {
                                if *epoch == stake.activation_epoch() {
                                    Some(rate.clone())
                                } else {
                                    None
                                }
                            })
                            .unwrap_or_default();
                        let estimated_reward = ((stake_rate.rate() / current_rate.rate()) - 1.0)
                            * stake.principal() as f64;
                        max(0, estimated_reward.round() as u64)
                    } else {
                        0
                    };
                    StakeStatus::Active { estimated_reward }
                } else {
                    StakeStatus::Pending
                };
                delegations.push(Stake {
                    staked_sui_id: stake.id(),
                    // TODO: this might change when we implement warm up period.
                    stake_request_epoch: stake.activation_epoch() - 1,
                    stake_active_epoch: stake.activation_epoch(),
                    principal: stake.principal(),
                    status,
                })
            }
            delegated_stakes.push(DelegatedStake {
                validator_address: rate_table.address,
                staking_pool: pool_id,
                stakes: delegations,
            })
        }
        Ok(delegated_stakes)
    }

    fn get_system_state(&self) -> Result<SuiSystemState, Error> {
        Ok(self.state.get_system_state()?)
    }
}

#[async_trait]
impl GovernanceReadApiServer for GovernanceReadApi {
    #[instrument(skip(self))]
    async fn get_stakes_by_ids(
        &self,
        staked_sui_ids: Vec<ObjectID>,
    ) -> RpcResult<Vec<DelegatedStake>> {
        with_tracing!(async move { self.get_stakes_by_ids(staked_sui_ids).await })
    }

    #[instrument(skip(self))]
    async fn get_stakes(&self, owner: SuiAddress) -> RpcResult<Vec<DelegatedStake>> {
        with_tracing!(async move { self.get_stakes(owner).await })
    }

    #[instrument(skip(self))]
    async fn get_committee_info(&self, epoch: Option<BigInt<u64>>) -> RpcResult<SuiCommittee> {
        with_tracing!(async move {
            self.state
                .get_or_latest_committee(epoch)
                .map(|committee| committee.into())
                .map_err(Error::from)
        })
    }

    #[instrument(skip(self))]
    async fn get_latest_sui_system_state(&self) -> RpcResult<SuiSystemStateSummary> {
        with_tracing!(async move {
            Ok(self
                .state
                .get_system_state()
                .map_err(Error::from)?
                .into_sui_system_state_summary())
        })
    }

    #[instrument(skip(self))]
    async fn get_reference_gas_price(&self) -> RpcResult<BigInt<u64>> {
        with_tracing!(async move {
            let epoch_store = self.state.load_epoch_store_one_call_per_task();
            Ok(epoch_store.reference_gas_price().into())
        })
    }

    #[instrument(skip(self))]
    async fn get_validators_apy(&self) -> RpcResult<ValidatorApys> {
        info!("get_validator_apy");
        let system_state_summary: SuiSystemStateSummary =
            self.get_latest_sui_system_state().await?;

        let exchange_rate_table = exchange_rates(&self.state, system_state_summary.epoch).await?;

        let apys = calculate_apys(
            system_state_summary.stake_subsidy_start_epoch,
            exchange_rate_table,
        );

        Ok(ValidatorApys {
            apys,
            epoch: system_state_summary.epoch,
        })
    }
}

pub fn calculate_apys(
    stake_subsidy_start_epoch: u64,
    exchange_rate_table: Vec<ValidatorExchangeRates>,
) -> Vec<ValidatorApy> {
    let mut apys = vec![];

    for rates in exchange_rate_table.into_iter().filter(|r| r.active) {
        // we start the apy calculation from the epoch when the stake subsidy starts
        let exchange_rates = rates.rates.into_iter().filter_map(|(epoch, rate)| {
            if epoch >= stake_subsidy_start_epoch {
                Some(rate)
            } else {
                None
            }
        });

        // we need at least 2 data points to calculate apy
        let average_apy = if exchange_rates.clone().count() >= 2 {
            // rates are sorted by epoch in descending order.
            let er_e = exchange_rates.clone().dropping(1);
            // rate e+1
            let er_e_1 = exchange_rates.dropping_back(1);
            let apys = er_e
                .zip(er_e_1)
                .map(calculate_apy)
                .filter(|apy| *apy > 0.0 && *apy < 0.1)
                .take(30)
                .collect::<Vec<_>>();

            let apy_counts = apys.len() as f64;
            apys.iter().sum::<f64>() / apy_counts
        } else {
            0.0
        };
        apys.push(ValidatorApy {
            address: rates.address,
            apy: average_apy,
        });
    }
    apys
}

#[test]
fn test_apys_calculation_filter_outliers() {
    // staking pool exchange rates extracted from mainnet
    let file =
        std::fs::File::open("src/unit_tests/data/validator_exchange_rate/rates.json").unwrap();
    let rates: BTreeMap<String, Vec<(u64, PoolTokenExchangeRate)>> =
        serde_json::from_reader(file).unwrap();

    let mut address_map = BTreeMap::new();

    let exchange_rates = rates
        .into_iter()
        .map(|(validator, rates)| {
            let address = SuiAddress::random_for_testing_only();
            address_map.insert(address, validator);
            ValidatorExchangeRates {
                address,
                pool_id: ObjectID::random(),
                active: true,
                rates,
            }
        })
        .collect();

    let apys = calculate_apys(20, exchange_rates);

    for apy in apys {
        println!("{}: {}", address_map[&apy.address], apy.apy);
        assert!(apy.apy < 0.07)
    }
}

// APY_e = (ER_e+1 / ER_e) ^ 365
fn calculate_apy((rate_e, rate_e_1): (PoolTokenExchangeRate, PoolTokenExchangeRate)) -> f64 {
    (rate_e.rate() / rate_e_1.rate()).powf(365.0) - 1.0
}

/// Cached exchange rates for validators for the given epoch, the cache size is 1, it will be cleared when the epoch changes.
/// rates are in descending order by epoch.
#[cached(
    type = "SizedCache<EpochId, Vec<ValidatorExchangeRates>>",
    create = "{ SizedCache::with_size(1) }",
    convert = "{ _current_epoch }",
    result = true
)]
async fn exchange_rates(
    state: &Arc<dyn StateRead>,
    _current_epoch: EpochId,
) -> RpcInterimResult<Vec<ValidatorExchangeRates>> {
    let system_state = state.get_system_state()?;
    let system_state_summary: SuiSystemStateSummary = system_state.into_sui_system_state_summary();

    // Get validator rate tables
    let mut tables = vec![];

    for validator in system_state_summary.active_validators {
        tables.push((
            validator.sui_address,
            validator.staking_pool_id,
            validator.exchange_rates_id,
            validator.exchange_rates_size,
            true,
        ));
    }

    // Get inactive validator rate tables
    for df in state.get_dynamic_fields(
        system_state_summary.inactive_pools_id,
        None,
        system_state_summary.inactive_pools_size as usize,
    )? {
        let pool_id: ID = bcs::from_bytes(&df.1.bcs_name).map_err(|e| {
            SuiErrorKind::ObjectDeserializationError {
                error: e.to_string(),
            }
        })?;
        let validator = get_validator_from_table(
            state.get_object_store().as_ref(),
            system_state_summary.inactive_pools_id,
            &pool_id,
        )?; // TODO(wlmyng): roll this into StateReadError
        tables.push((
            validator.sui_address,
            validator.staking_pool_id,
            validator.exchange_rates_id,
            validator.exchange_rates_size,
            false,
        ));
    }

    let mut exchange_rates = vec![];
    // Get exchange rates for each validator
    for (address, pool_id, exchange_rates_id, exchange_rates_size, active) in tables {
        let mut rates = state
            .get_dynamic_fields(exchange_rates_id, None, exchange_rates_size as usize)?
            .into_iter()
            .map(|df| {
                let epoch: EpochId = bcs::from_bytes(&df.1.bcs_name).map_err(|e| {
                    SuiErrorKind::ObjectDeserializationError {
                        error: e.to_string(),
                    }
                })?;

                let exchange_rate: PoolTokenExchangeRate = get_dynamic_field_from_store(
                    &state.get_object_store().as_ref(),
                    exchange_rates_id,
                    &epoch,
                )?;

                Ok::<_, SuiError>((epoch, exchange_rate))
            })
            .collect::<Result<Vec<_>, _>>()?;

        // Rates for some epochs might be missing due to safe mode, we need to backfill them.
        rates = backfill_rates(rates);

        exchange_rates.push(ValidatorExchangeRates {
            address,
            pool_id,
            active,
            rates,
        });
    }
    Ok(exchange_rates)
}

#[derive(Clone, Debug)]
pub struct ValidatorExchangeRates {
    pub address: SuiAddress,
    pub pool_id: ObjectID,
    pub active: bool,
    pub rates: Vec<(EpochId, PoolTokenExchangeRate)>,
}

/// Backfill missing rates for some epochs due to safe mode. If a rate is missing for epoch e,
/// we will use the rate for epoch e-1 to fill it.
/// Rates returned are in descending order by epoch.
fn backfill_rates(
    rates: Vec<(EpochId, PoolTokenExchangeRate)>,
) -> Vec<(EpochId, PoolTokenExchangeRate)> {
    if rates.is_empty() {
        return rates;
    }

    let min_epoch = *rates.iter().map(|(e, _)| e).min().unwrap();
    let max_epoch = *rates.iter().map(|(e, _)| e).max().unwrap();
    let mut filled_rates = Vec::new();
    let mut prev_rate = None;

    for epoch in min_epoch..=max_epoch {
        match rates.iter().find(|(e, _)| *e == epoch) {
            Some((e, rate)) => {
                prev_rate = Some(rate.clone());
                filled_rates.push((*e, rate.clone()));
            }
            None => {
                if let Some(rate) = prev_rate.clone() {
                    filled_rates.push((epoch, rate));
                }
            }
        }
    }
    filled_rates.reverse();
    filled_rates
}

impl SuiRpcModule for GovernanceReadApi {
    fn rpc(self) -> RpcModule<Self> {
        self.into_rpc()
    }

    fn rpc_doc_module() -> Module {
        GovernanceReadApiOpenRpc::module_doc()
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use sui_types::sui_system_state::PoolTokenExchangeRate;

    #[test]
    fn test_backfill_rates_empty() {
        let rates = vec![];
        assert_eq!(backfill_rates(rates), vec![]);
    }

    #[test]
    fn test_backfill_rates_no_gaps() {
        let rate1 = PoolTokenExchangeRate::new(100, 100);
        let rate2 = PoolTokenExchangeRate::new(200, 220);
        let rate3 = PoolTokenExchangeRate::new(300, 330);
        let rates = vec![(2, rate2.clone()), (3, rate3.clone()), (1, rate1.clone())];

        let expected: Vec<(u64, PoolTokenExchangeRate)> =
            vec![(3, rate3.clone()), (2, rate2), (1, rate1)];
        assert_eq!(backfill_rates(rates), expected);
    }

    #[test]
    fn test_backfill_rates_with_gaps() {
        let rate1 = PoolTokenExchangeRate::new(100, 100);
        let rate3 = PoolTokenExchangeRate::new(300, 330);
        let rate5 = PoolTokenExchangeRate::new(500, 550);
        let rates = vec![(3, rate3.clone()), (1, rate1.clone()), (5, rate5.clone())];

        let expected = vec![
            (5, rate5.clone()),
            (4, rate3.clone()),
            (3, rate3.clone()),
            (2, rate1.clone()),
            (1, rate1),
        ];
        assert_eq!(backfill_rates(rates), expected);
    }
}