refactor: add count parameter to get_update and use 128 as the limit (#97)

* Make get_update take count. Limit count to 128 as specified in the spec

* use u8 instead of u32

* run cargo fmt to fix formating

* fix compilation in tests

* moved constants module into the consensus package

consensus/src/consensus.rs

@@ -13,6 +13,7 @@ use common::types::*;
 use common::utils::*;
 use config::Config;
 
+use crate::constants::MAX_REQUEST_LIGHT_CLIENT_UPDATES;
 use crate::errors::ConsensusError;
 
 use super::rpc::ConsensusRpc;
@@ -96,7 +97,10 @@ impl<R: ConsensusRpc> ConsensusClient<R> {
         self.bootstrap().await?;
 
         let current_period = calc_sync_period(self.store.finalized_header.slot);
-        let updates = self.rpc.get_updates(current_period).await?;
+        let updates = self
+            .rpc
+            .get_updates(current_period, MAX_REQUEST_LIGHT_CLIENT_UPDATES)
+            .await?;
 
         for mut update in updates {
             self.verify_update(&mut update)?;
@@ -126,7 +130,7 @@ impl<R: ConsensusRpc> ConsensusClient<R> {
         if self.store.next_sync_committee.is_none() {
             debug!("checking for sync committee update");
             let current_period = calc_sync_period(self.store.finalized_header.slot);
-            let mut updates = self.rpc.get_updates(current_period).await?;
+            let mut updates = self.rpc.get_updates(current_period, 1).await?;
 
             if updates.len() == 1 {
                 let mut update = updates.get_mut(0).unwrap();
@@ -558,6 +562,7 @@ fn is_current_committee_proof_valid(
 mod tests {
     use std::sync::Arc;
 
+    use crate::constants::MAX_REQUEST_LIGHT_CLIENT_UPDATES;
     use ssz_rs::Vector;
 
     use crate::{
@@ -593,7 +598,11 @@ mod tests {
     async fn test_verify_update() {
         let client = get_client().await;
         let period = calc_sync_period(client.store.finalized_header.slot);
-        let updates = client.rpc.get_updates(period).await.unwrap();
+        let updates = client
+            .rpc
+            .get_updates(period, MAX_REQUEST_LIGHT_CLIENT_UPDATES)
+            .await
+            .unwrap();
 
         let mut update = updates[0].clone();
         client.verify_update(&mut update).unwrap();
@@ -603,7 +612,11 @@ mod tests {
     async fn test_verify_update_invalid_committee() {
         let client = get_client().await;
         let period = calc_sync_period(client.store.finalized_header.slot);
-        let updates = client.rpc.get_updates(period).await.unwrap();
+        let updates = client
+            .rpc
+            .get_updates(period, MAX_REQUEST_LIGHT_CLIENT_UPDATES)
+            .await
+            .unwrap();
 
         let mut update = updates[0].clone();
         update.next_sync_committee.pubkeys[0] = Vector::default();
@@ -619,7 +632,11 @@ mod tests {
     async fn test_verify_update_invalid_finality() {
         let client = get_client().await;
         let period = calc_sync_period(client.store.finalized_header.slot);
-        let updates = client.rpc.get_updates(period).await.unwrap();
+        let updates = client
+            .rpc
+            .get_updates(period, MAX_REQUEST_LIGHT_CLIENT_UPDATES)
+            .await
+            .unwrap();
 
         let mut update = updates[0].clone();
         update.finalized_header = Header::default();
@@ -635,7 +652,11 @@ mod tests {
     async fn test_verify_update_invalid_sig() {
         let client = get_client().await;
         let period = calc_sync_period(client.store.finalized_header.slot);
-        let updates = client.rpc.get_updates(period).await.unwrap();
+        let updates = client
+            .rpc
+            .get_updates(period, MAX_REQUEST_LIGHT_CLIENT_UPDATES)
+            .await
+            .unwrap();
 
         let mut update = updates[0].clone();
         update.sync_aggregate.sync_committee_signature = Vector::default();

consensus/src/constants.rs

@@ -0,0 +1,4 @@
+// Consensus constants
+
+// https://github.com/ethereum/consensus-specs/blob/dev/specs/altair/light-client/p2p-interface.md#configuration
+pub const MAX_REQUEST_LIGHT_CLIENT_UPDATES: u8 = 128;

consensus/src/lib.rs

@@ -5,4 +5,5 @@ pub mod types;
 mod consensus;
 pub use crate::consensus::*;
 
+mod constants;
 mod utils;

consensus/src/rpc/mock_rpc.rs

@@ -23,7 +23,7 @@ impl ConsensusRpc for MockRpc {
         Ok(serde_json::from_str(&bootstrap)?)
     }
 
-    async fn get_updates(&self, _period: u64) -> Result<Vec<Update>> {
+    async fn get_updates(&self, _period: u64, _count: u8) -> Result<Vec<Update>> {
         let updates = read_to_string(self.testdata.join("updates.json"))?;
         Ok(serde_json::from_str(&updates)?)
     }

consensus/src/rpc/mod.rs

@@ -11,7 +11,7 @@ use crate::types::{BeaconBlock, Bootstrap, FinalityUpdate, OptimisticUpdate, Upd
 pub trait ConsensusRpc {
     fn new(path: &str) -> Self;
     async fn get_bootstrap(&self, block_root: &Vec<u8>) -> Result<Bootstrap>;
-    async fn get_updates(&self, period: u64) -> Result<Vec<Update>>;
+    async fn get_updates(&self, period: u64, count: u8) -> Result<Vec<Update>>;
     async fn get_finality_update(&self) -> Result<FinalityUpdate>;
     async fn get_optimistic_update(&self) -> Result<OptimisticUpdate>;
     async fn get_block(&self, slot: u64) -> Result<BeaconBlock>;

consensus/src/rpc/nimbus_rpc.rs

@@ -3,8 +3,10 @@ use common::errors::RpcError;
 use eyre::Result;
 use reqwest_middleware::{ClientBuilder, ClientWithMiddleware};
 use reqwest_retry::{policies::ExponentialBackoff, RetryTransientMiddleware};
+use std::cmp;
 
 use super::ConsensusRpc;
+use crate::constants::MAX_REQUEST_LIGHT_CLIENT_UPDATES;
 use crate::types::*;
 
 pub struct NimbusRpc {
@@ -49,10 +51,11 @@ impl ConsensusRpc for NimbusRpc {
         Ok(res.data)
     }
 
-    async fn get_updates(&self, period: u64) -> Result<Vec<Update>> {
+    async fn get_updates(&self, period: u64, count: u8) -> Result<Vec<Update>> {
+        let count = cmp::min(count, MAX_REQUEST_LIGHT_CLIENT_UPDATES);
         let req = format!(
-            "{}/eth/v1/beacon/light_client/updates?start_period={}&count=1000",
+            "{}/eth/v1/beacon/light_client/updates?start_period={}&count={}",
-            self.rpc, period
+            self.rpc, period, count
         );
 
         let res = self