CLI query to estimate staking rewards rate

crates/apps_lib/src/cli.rs

@@ -298,6 +298,7 @@ pub mod cmds {
                 .subcommand(QueryMetaData::def().display_order(5))
                 .subcommand(QueryTotalSupply::def().display_order(5))
                 .subcommand(QueryEffNativeSupply::def().display_order(5))
+                .subcommand(QueryStakingRewardsRate::def().display_order(5))
                 // Actions
                 .subcommand(SignTx::def().display_order(6))
                 .subcommand(ShieldedSync::def().display_order(6))
@@ -373,6 +374,8 @@ pub mod cmds {
                 Self::parse_with_ctx(matches, QueryTotalSupply);
             let query_native_supply =
                 Self::parse_with_ctx(matches, QueryEffNativeSupply);
+            let query_staking_rewards_rate =
+                Self::parse_with_ctx(matches, QueryStakingRewardsRate);
             let query_find_validator =
                 Self::parse_with_ctx(matches, QueryFindValidator);
             let query_result = Self::parse_with_ctx(matches, QueryResult);
@@ -449,6 +452,7 @@ pub mod cmds {
                 .or(query_metadata)
                 .or(query_total_supply)
                 .or(query_native_supply)
+                .or(query_staking_rewards_rate)
                 .or(query_account)
                 .or(sign_tx)
                 .or(shielded_sync)
@@ -534,6 +538,7 @@ pub mod cmds {
         QueryDelegations(QueryDelegations),
         QueryTotalSupply(QueryTotalSupply),
         QueryEffNativeSupply(QueryEffNativeSupply),
+        QueryStakingRewardsRate(QueryStakingRewardsRate),
         QueryFindValidator(QueryFindValidator),
         QueryRawBytes(QueryRawBytes),
         QueryProposal(QueryProposal),
@@ -2118,6 +2123,36 @@ pub mod cmds {
         }
     }
 
+    #[derive(Clone, Debug)]
+    pub struct QueryStakingRewardsRate(
+        pub args::QueryStakingRewardsRate<args::CliTypes>,
+    );
+
+    impl SubCmd for QueryStakingRewardsRate {
+        const CMD: &'static str = "staking-rewards-rate";
+
+        fn parse(matches: &ArgMatches) -> Option<Self>
+        where
+            Self: Sized,
+        {
+            matches.subcommand_matches(Self::CMD).map(|matches| {
+                QueryStakingRewardsRate(args::QueryStakingRewardsRate::parse(
+                    matches,
+                ))
+            })
+        }
+
+        fn def() -> App {
+            App::new(Self::CMD)
+                .about(wrap!(
+                    "Query the latest estimate of the staking rewards rate \
+                     based on the most recent minted inflation amount at the \
+                     last epoch change."
+                ))
+                .add_args::<args::QueryStakingRewardsRate<args::CliTypes>>()
+        }
+    }
+
     #[derive(Clone, Debug)]
     pub struct QueryFindValidator(pub args::QueryFindValidator<args::CliTypes>);
 
@@ -7155,6 +7190,32 @@ pub mod args {
         }
     }
 
+    impl Args for QueryStakingRewardsRate<CliTypes> {
+        fn parse(matches: &ArgMatches) -> Self {
+            let query = Query::parse(matches);
+            Self { query }
+        }
+
+        fn def(app: App) -> App {
+            app.add_args::<Query<CliTypes>>()
+        }
+    }
+
+    impl CliToSdk<QueryStakingRewardsRate<SdkTypes>>
+        for QueryStakingRewardsRate<CliTypes>
+    {
+        type Error = std::convert::Infallible;
+
+        fn to_sdk(
+            self,
+            ctx: &mut Context,
+        ) -> Result<QueryStakingRewardsRate<SdkTypes>, Self::Error> {
+            Ok(QueryStakingRewardsRate::<SdkTypes> {
+                query: self.query.to_sdk(ctx)?,
+            })
+        }
+    }
+
     impl Args for QueryFindValidator<CliTypes> {
         fn parse(matches: &ArgMatches) -> Self {
             let query = Query::parse(matches);

crates/apps_lib/src/cli/client.rs

@@ -661,6 +661,19 @@ impl CliApi {
                         let namada = ctx.to_sdk(client, io);
                         rpc::query_effective_native_supply(&namada).await;
                     }
+                    Sub::QueryStakingRewardsRate(QueryStakingRewardsRate(
+                        args,
+                    )) => {
+                        let chain_ctx = ctx.borrow_mut_chain_or_exit();
+                        let ledger_address =
+                            chain_ctx.get(&args.query.ledger_address);
+                        let client = client.unwrap_or_else(|| {
+                            C::from_tendermint_address(&ledger_address)
+                        });
+                        client.wait_until_node_is_synced(&io).await?;
+                        let namada = ctx.to_sdk(client, io);
+                        rpc::query_staking_rewards_rate(&namada).await;
+                    }
                     Sub::QueryFindValidator(QueryFindValidator(args)) => {
                         let chain_ctx = ctx.borrow_mut_chain_or_exit();
                         let ledger_address =

crates/apps_lib/src/client/rpc.rs

@@ -1364,6 +1364,21 @@ pub async fn query_effective_native_supply<N: Namada>(context: &N) {
     display_line!(context.io(), "nam: {}", native_supply.to_string_native());
 }
 
+/// Query the staking rewards rate estimate
+pub async fn query_staking_rewards_rate<N: Namada>(context: &N) {
+    let rewards_rate = unwrap_client_response::<N::Client, Dec>(
+        RPC.vp()
+            .token()
+            .staking_rewards_rate(context.client())
+            .await,
+    );
+    display_line!(
+        context.io(),
+        "Current annual staking rewards rate: {}",
+        rewards_rate
+    );
+}
+
 /// Query a validator's state information
 pub async fn query_and_print_validator_state(
     context: &impl Namada,

crates/proof_of_stake/src/rewards.rs

@@ -655,6 +655,41 @@ where
     Ok(storage.read::<token::Amount>(&key)?.unwrap_or_default())
 }
 
+/// Compute an estimation of the most recent staking rewards rate.
+pub fn estimate_staking_reward_rate<S, Token, Parameters>(
+    storage: &S,
+) -> Result<Dec>
+where
+    S: StorageRead,
+    Parameters: parameters::Read<S>,
+    Token: trans_token::Read<S> + trans_token::Write<S>,
+{
+    // Get needed data in desired form
+    let total_native_tokens =
+        Token::get_effective_total_native_supply(storage)?;
+    let last_staked_ratio = read_last_staked_ratio(storage)?
+        .expect("Last staked ratio should exist in PoS storage");
+    let last_inflation_amount = read_last_pos_inflation_amount(storage)?
+        .expect("Last inflation amount should exist in PoS storage");
+    let epochs_per_year: u64 = Parameters::epochs_per_year(storage)?;
+
+    let total_native_tokens =
+        Dec::try_from(total_native_tokens).into_storage_result()?;
+    let last_inflation_amount =
+        Dec::try_from(last_inflation_amount).into_storage_result()?;
+
+    // Estimate annual inflation rate
+    let est_inflation_rate = checked!(
+        last_inflation_amount * epochs_per_year / total_native_tokens
+    )?;
+
+    // Estimate annual staking rewards rate
+    let est_staking_reward_rate =
+        checked!(est_inflation_rate / last_staked_ratio)?;
+
+    Ok(est_staking_reward_rate)
+}
+
 #[cfg(test)]
 mod tests {
     use std::str::FromStr;

crates/sdk/src/args.rs

@@ -2245,6 +2245,13 @@ pub struct QueryEffNativeSupply<C: NamadaTypes = SdkTypes> {
     pub query: Query<C>,
 }
 
+/// Query estimate of staking rewards rate
+#[derive(Clone, Debug)]
+pub struct QueryStakingRewardsRate<C: NamadaTypes = SdkTypes> {
+    /// Common query args
+    pub query: Query<C>,
+}
+
 /// Query PoS to find a validator
 #[derive(Clone, Debug)]
 pub struct QueryFindValidator<C: NamadaTypes = SdkTypes> {

crates/sdk/src/queries/vp/token.rs

@@ -2,9 +2,10 @@
 
 use namada_core::address::Address;
 use namada_core::token;
+use namada_proof_of_stake::rewards::estimate_staking_reward_rate;
 use namada_state::{DBIter, StorageHasher, DB};
 use namada_token::{
-    get_effective_total_native_supply, read_denom, read_total_supply,
+    get_effective_total_native_supply, read_denom, read_total_supply, Dec,
 };
 
 use crate::queries::RequestCtx;
@@ -13,6 +14,7 @@ router! {TOKEN,
     ( "denomination" / [token: Address] ) -> Option<token::Denomination> = denomination,
     ( "total_supply" / [token: Address] ) -> token::Amount = total_supply,
     ( "effective_native_supply" ) -> token::Amount = effective_native_supply,
+    ( "staking_rewards_rate" ) -> Dec = staking_rewards_rate,
 }
 
 /// Get the number of decimal places (in base 10) for a
@@ -51,6 +53,21 @@ where
     get_effective_total_native_supply(ctx.state)
 }
 
+/// Get the effective total supply of the native token
+fn staking_rewards_rate<D, H, V, T>(
+    ctx: RequestCtx<'_, D, H, V, T>,
+) -> namada_storage::Result<Dec>
+where
+    D: 'static + DB + for<'iter> DBIter<'iter> + Sync,
+    H: 'static + StorageHasher + Sync,
+{
+    estimate_staking_reward_rate::<
+        _,
+        crate::token::Store<_>,
+        crate::parameters::Store<_>,
+    >(ctx.state)
+}
+
 pub mod client_only_methods {
     use borsh::BorshDeserialize;
     use namada_core::address::Address;

crates/sdk/src/rpc.rs

@@ -44,6 +44,7 @@ use namada_proof_of_stake::types::{
 };
 use namada_state::LastBlock;
 use namada_token::masp::MaspTokenRewardData;
+use namada_token::Dec;
 use namada_tx::data::{BatchedTxResult, DryRunResult, ResultCode, TxResult};
 use namada_tx::event::{Batch as BatchAttr, Code as CodeAttr};
 use serde::Serialize;
@@ -235,6 +236,15 @@ pub async fn get_effective_native_supply<C: Client + Sync>(
     )
 }
 
+/// Query the effective total supply of the native token
+pub async fn get_staking_rewards_rate<C: Client + Sync>(
+    client: &C,
+) -> Result<Dec, error::Error> {
+    convert_response::<C, _>(
+        RPC.vp().token().staking_rewards_rate(client).await,
+    )
+}
+
 /// Check if the given address is a known validator.
 pub async fn is_validator<C: namada_io::Client + Sync>(
     client: &C,