feat(rpc): add protocol config rpc endpoint (#3919)

Add `EXPERIMENTAL_protocol_config` rpc endpoint that returns the protocol config given some block, since protocol config can change after genesis due to protocol upgrades. This will allow users to get the up-to-date protocol-level configs. Fixes #3918.

Test plan
----------
`test_protocol_config_rpc`

chain/chain/src/test_utils.rs

@@ -44,6 +44,7 @@ use crate::types::{ApplyTransactionResult, BlockHeaderInfo, ChainGenesis};
 #[cfg(feature = "protocol_feature_block_header_v3")]
 use crate::Doomslug;
 use crate::{BlockHeader, DoomslugThresholdMode, RuntimeAdapter};
+use near_chain_configs::ProtocolConfig;
 #[cfg(feature = "protocol_feature_block_header_v3")]
 use near_primitives::block_header::{Approval, ApprovalInner};
 
@@ -1014,6 +1015,10 @@ impl RuntimeAdapter for KeyValueRuntime {
         // See https://github.com/ethereum-lists/chains/blob/master/_data/chains/1313161555.json
         1313161555
     }
+
+    fn get_protocol_config(&self, _epoch_id: &EpochId) -> Result<ProtocolConfig, Error> {
+        unreachable!("get_protocol_config should not be called in KeyValueRuntime");
+    }
 }
 
 pub fn setup() -> (Chain, Arc<KeyValueRuntime>, Arc<InMemoryValidatorSigner>) {

chain/chain/src/types.rs

@@ -7,7 +7,7 @@ use chrono::{DateTime, Utc};
 use num_rational::Rational;
 use serde::Serialize;
 
-use near_chain_configs::GenesisConfig;
+use near_chain_configs::{GenesisConfig, ProtocolConfig};
 use near_chain_primitives::Error;
 use near_crypto::Signature;
 use near_pool::types::PoolIterator;
@@ -604,6 +604,8 @@ pub trait RuntimeAdapter: Send + Sync {
     #[cfg(feature = "protocol_feature_evm")]
     fn evm_chain_id(&self) -> u64;
 
+    fn get_protocol_config(&self, epoch_id: &EpochId) -> Result<ProtocolConfig, Error>;
+
     /// Build receipts hashes.
     // Due to borsh serialization constraints, we have to use `&Vec<Receipt>` instead of `&[Receipt]`
     // here.

chain/client-primitives/Cargo.toml

@@ -14,6 +14,8 @@ strum = { version = "0.20", features = ["derive"] }
 thiserror = "1.0"
 
 near-chain-primitives = { path = "../chain-primitives" }
+near-chain-configs = { path = "../../core/chain-configs" }
+
 near-chunks = { path = "../chunks" }
 near-network = { path = "../network" }
 near-primitives = { path = "../../core/primitives" }

chain/client-primitives/src/types.rs

@@ -8,6 +8,7 @@ use actix::Message;
 use chrono::{DateTime, Utc};
 use serde::{Deserialize, Serialize};
 
+use near_chain_configs::ProtocolConfigView;
 use near_network::types::{AccountOrPeerIdOrHash, KnownProducer};
 use near_network::PeerInfo;
 use near_primitives::errors::InvalidTxError;
@@ -449,3 +450,33 @@ impl From<near_chain_primitives::Error> for GetReceiptError {
 impl Message for GetReceipt {
     type Result = Result<Option<ReceiptView>, GetReceiptError>;
 }
+
+pub struct GetProtocolConfig(pub BlockReference);
+
+impl Message for GetProtocolConfig {
+    type Result = Result<ProtocolConfigView, GetProtocolConfigError>;
+}
+
+#[derive(thiserror::Error, Debug)]
+pub enum GetProtocolConfigError {
+    #[error("IO Error: {0}")]
+    IOError(String),
+    #[error("Block has never been observed: {0}")]
+    UnknownBlock(String),
+    // NOTE: Currently, the underlying errors are too broad, and while we tried to handle
+    // expected cases, we cannot statically guarantee that no other errors will be returned
+    // in the future.
+    // TODO #3851: Remove this variant once we can exhaustively match all the underlying errors
+    #[error("It is a bug if you receive this error type, please, report this incident: https://github.com/near/nearcore/issues/new/choose. Details: {0}")]
+    Unreachable(String),
+}
+
+impl From<near_chain_primitives::Error> for GetProtocolConfigError {
+    fn from(error: near_chain_primitives::Error) -> Self {
+        match error.kind() {
+            near_chain_primitives::ErrorKind::IOErr(s) => Self::IOError(s),
+            near_chain_primitives::ErrorKind::DBNotFoundErr(s) => Self::UnknownBlock(s),
+            _ => Self::Unreachable(error.to_string()),
+        }
+    }
+}

chain/client/src/lib.rs

@@ -4,9 +4,9 @@ extern crate lazy_static;
 pub use near_client_primitives::types::{
     Error, GetBlock, GetBlockProof, GetBlockProofResponse, GetBlockWithMerkleTree, GetChunk,
     GetExecutionOutcome, GetExecutionOutcomeResponse, GetExecutionOutcomesForBlock, GetGasPrice,
-    GetNetworkInfo, GetNextLightClientBlock, GetReceipt, GetStateChanges, GetStateChangesInBlock,
-    GetStateChangesWithCauseInBlock, GetValidatorInfo, GetValidatorOrdered, Query, Status,
-    StatusResponse, SyncStatus, TxStatus, TxStatusError,
+    GetNetworkInfo, GetNextLightClientBlock, GetProtocolConfig, GetReceipt, GetStateChanges,
+    GetStateChangesInBlock, GetStateChangesWithCauseInBlock, GetValidatorInfo, GetValidatorOrdered,
+    Query, Status, StatusResponse, SyncStatus, TxStatus, TxStatusError,
 };
 
 pub use crate::client::Client;

chain/client/src/view_client.rs

@@ -15,7 +15,7 @@ use near_chain::{
     get_epoch_block_producers_view, Chain, ChainGenesis, ChainStoreAccess, DoomslugThresholdMode,
     ErrorKind, RuntimeAdapter,
 };
-use near_chain_configs::ClientConfig;
+use near_chain_configs::{ClientConfig, ProtocolConfigView};
 #[cfg(feature = "adversarial")]
 use near_network::types::NetworkAdversarialMessage;
 use near_network::types::{
@@ -49,8 +49,9 @@ use crate::{
 };
 use near_client_primitives::types::{
     Error, GetBlock, GetBlockError, GetBlockProof, GetBlockProofResponse, GetBlockWithMerkleTree,
-    GetChunkError, GetExecutionOutcome, GetExecutionOutcomesForBlock, GetGasPrice, GetReceipt,
-    GetReceiptError, GetStateChangesWithCauseInBlock, Query, TxStatus, TxStatusError,
+    GetChunkError, GetExecutionOutcome, GetExecutionOutcomesForBlock, GetGasPrice,
+    GetProtocolConfig, GetProtocolConfigError, GetReceipt, GetReceiptError,
+    GetStateChangesWithCauseInBlock, Query, TxStatus, TxStatusError,
 };
 use near_performance_metrics_macros::perf;
 use near_performance_metrics_macros::perf_with_debug;
@@ -804,6 +805,40 @@ impl Handler<GetBlockProof> for ViewClientActor {
     }
 }
 
+impl Handler<GetProtocolConfig> for ViewClientActor {
+    type Result = Result<ProtocolConfigView, GetProtocolConfigError>;
+
+    #[perf]
+    fn handle(&mut self, msg: GetProtocolConfig, _: &mut Self::Context) -> Self::Result {
+        let block_header = match msg.0 {
+            BlockReference::Finality(finality) => {
+                let block_hash = self.get_block_hash_by_finality(&finality)?;
+                self.chain.get_block_header(&block_hash).map(Clone::clone)
+            }
+            BlockReference::BlockId(BlockId::Height(height)) => {
+                self.chain.get_header_by_height(height).map(Clone::clone)
+            }
+            BlockReference::BlockId(BlockId::Hash(hash)) => {
+                self.chain.get_block_header(&hash).map(Clone::clone)
+            }
+            BlockReference::SyncCheckpoint(sync_checkpoint) => {
+                if let Some(block_hash) =
+                    self.get_block_hash_by_sync_checkpoint(&sync_checkpoint)?
+                {
+                    self.chain.get_block_header(&block_hash).map(Clone::clone)
+                } else {
+                    return Err(GetProtocolConfigError::UnknownBlock(format!(
+                        "{:?}",
+                        sync_checkpoint
+                    )));
+                }
+            }
+        }?;
+        let config = self.runtime_adapter.get_protocol_config(block_header.epoch_id())?;
+        Ok(config.into())
+    }
+}
+
 impl Handler<NetworkViewClientMessages> for ViewClientActor {
     type Result = NetworkViewClientResponses;
 

chain/jsonrpc-primitives/Cargo.toml

@@ -17,3 +17,4 @@ uuid = { version = "~0.8", features = ["v4"] }
 near-client-primitives = { path = "../client-primitives" }
 near-primitives = { path = "../../core/primitives" }
 near-metrics = { path = "../../core/metrics" }
+near-chain-configs = { path = "../../core/chain-configs" }

chain/jsonrpc-primitives/src/types/config.rs

@@ -0,0 +1,78 @@
+use crate::types::blocks::BlockReference;
+use serde::{Deserialize, Serialize};
+use serde_json::Value;
+
+#[derive(Serialize, Deserialize)]
+pub struct RpcProtocolConfigRequest {
+    #[serde(flatten)]
+    pub block_reference: BlockReference,
+}
+
+impl RpcProtocolConfigRequest {
+    pub fn parse(
+        value: Option<Value>,
+    ) -> Result<RpcProtocolConfigRequest, crate::errors::RpcParseError> {
+        crate::utils::parse_params::<BlockReference>(value)
+            .map(|block_reference| RpcProtocolConfigRequest { block_reference })
+    }
+}
+
+#[derive(Serialize, Deserialize)]
+pub struct RpcProtocolConfigResponse {
+    #[serde(flatten)]
+    pub config_view: near_chain_configs::ProtocolConfigView,
+}
+
+#[derive(thiserror::Error, Debug)]
+pub enum RpcProtocolConfigError {
+    #[error("Block has never been observed: {0}")]
+    UnknownBlock(String),
+    #[error("The node reached its limits. Try again later. More details: {0}")]
+    InternalError(String),
+    // NOTE: Currently, the underlying errors are too broad, and while we tried to handle
+    // expected cases, we cannot statically guarantee that no other errors will be returned
+    // in the future.
+    // TODO #3851: Remove this variant once we can exhaustively match all the underlying errors
+    #[error("It is a bug if you receive this error type, please, report this incident: https://github.com/near/nearcore/issues/new/choose. Details: {0}")]
+    Unreachable(String),
+}
+
+impl From<near_client_primitives::types::GetProtocolConfigError> for RpcProtocolConfigError {
+    fn from(error: near_client_primitives::types::GetProtocolConfigError) -> Self {
+        match error {
+            near_client_primitives::types::GetProtocolConfigError::UnknownBlock(s) => {
+                Self::UnknownBlock(s)
+            }
+            near_client_primitives::types::GetProtocolConfigError::IOError(s) => {
+                Self::InternalError(s)
+            }
+            near_client_primitives::types::GetProtocolConfigError::Unreachable(s) => {
+                near_metrics::inc_counter_vec(
+                    &crate::metrics::RPC_UNREACHABLE_ERROR_COUNT,
+                    &["RpcProtocolConfigError", &s],
+                );
+                Self::Unreachable(s)
+            }
+        }
+    }
+}
+
+impl From<actix::MailboxError> for RpcProtocolConfigError {
+    fn from(error: actix::MailboxError) -> Self {
+        Self::InternalError(error.to_string())
+    }
+}
+
+impl From<RpcProtocolConfigError> for crate::errors::RpcError {
+    fn from(error: RpcProtocolConfigError) -> Self {
+        let error_data = match error {
+            RpcProtocolConfigError::UnknownBlock(hash) => {
+                Some(Value::String(format!("Block Not Found: {}", hash)))
+            }
+            RpcProtocolConfigError::Unreachable(s) => Some(Value::String(s)),
+            RpcProtocolConfigError::InternalError(_) => Some(Value::String(error.to_string())),
+        };
+
+        Self::new(-32_000, "Server error".to_string(), error_data)
+    }
+}

chain/jsonrpc-primitives/src/types/mod.rs

@@ -1,3 +1,4 @@
 pub mod blocks;
 pub mod chunks;
+pub mod config;
 pub mod receipts;

chain/jsonrpc/client/src/lib.rs

@@ -233,6 +233,14 @@ impl JsonRpcClient {
     ) -> RpcRequest<near_jsonrpc_primitives::types::receipts::RpcReceiptResponse> {
         call_method(&self.client, &self.server_addr, "EXPERIMENTAL_receipt", request)
     }
+
+    #[allow(non_snake_case)]
+    pub fn EXPERIMENTAL_protocol_config(
+        &self,
+        request: near_jsonrpc_primitives::types::config::RpcProtocolConfigRequest,
+    ) -> RpcRequest<near_jsonrpc_primitives::types::config::RpcProtocolConfigResponse> {
+        call_method(&self.client, &self.server_addr, "EXPERIMENTAL_protocol_config", request)
+    }
 }
 
 fn create_client() -> Client {

chain/jsonrpc/src/lib.rs

@@ -17,8 +17,9 @@ use tokio::time::{sleep, timeout};
 use near_chain_configs::GenesisConfig;
 use near_client::{
     ClientActor, GetBlock, GetBlockProof, GetChunk, GetExecutionOutcome, GetGasPrice,
-    GetNetworkInfo, GetNextLightClientBlock, GetReceipt, GetStateChanges, GetStateChangesInBlock,
-    GetValidatorInfo, GetValidatorOrdered, Query, Status, TxStatus, TxStatusError, ViewClientActor,
+    GetNetworkInfo, GetNextLightClientBlock, GetProtocolConfig, GetReceipt, GetStateChanges,
+    GetStateChangesInBlock, GetValidatorInfo, GetValidatorOrdered, Query, Status, TxStatus,
+    TxStatusError, ViewClientActor,
 };
 pub use near_jsonrpc_client as client;
 use near_jsonrpc_primitives::errors::RpcError;
@@ -29,6 +30,7 @@ use near_jsonrpc_primitives::rpc::{
     RpcStateChangesInBlockResponse, RpcStateChangesRequest, RpcStateChangesResponse,
     RpcValidatorsOrderedRequest, TransactionInfo,
 };
+use near_jsonrpc_primitives::types::config::RpcProtocolConfigResponse;
 use near_metrics::{Encoder, TextEncoder};
 #[cfg(feature = "adversarial")]
 use near_network::types::{NetworkAdversarialMessage, NetworkViewClientMessages};
@@ -248,6 +250,14 @@ impl JsonRpcHandler {
             "EXPERIMENTAL_changes_in_block" => self.changes_in_block(request.params).await,
             "EXPERIMENTAL_check_tx" => self.check_tx(request.params).await,
             "EXPERIMENTAL_genesis_config" => self.genesis_config().await,
+            "EXPERIMENTAL_protocol_config" => {
+                let rpc_protocol_config_request =
+                    near_jsonrpc_primitives::types::config::RpcProtocolConfigRequest::parse(
+                        request.params,
+                    )?;
+                let config = self.protocol_config(rpc_protocol_config_request).await?;
+                serde_json::to_value(config).map_err(|err| RpcError::parse_error(err.to_string()))
+            }
             "EXPERIMENTAL_light_client_proof" => {
                 self.light_client_execution_outcome_proof(request.params).await
             }
@@ -533,6 +543,20 @@ impl JsonRpcHandler {
         jsonify(Ok(Ok(&self.genesis_config)))
     }
 
+    pub async fn protocol_config(
+        &self,
+        request_data: near_jsonrpc_primitives::types::config::RpcProtocolConfigRequest,
+    ) -> Result<
+        near_jsonrpc_primitives::types::config::RpcProtocolConfigResponse,
+        near_jsonrpc_primitives::types::config::RpcProtocolConfigError,
+    > {
+        let config_view = self
+            .view_client_addr
+            .send(GetProtocolConfig(request_data.block_reference.into()))
+            .await??;
+        Ok(RpcProtocolConfigResponse { config_view })
+    }
+
     async fn query(&self, params: Option<Value>) -> Result<Value, RpcError> {
         let query_request = if let Ok((path, data)) =
             parse_params::<(String, String)>(params.clone())