Add `getSnapshotSlot` RPC method

client/src/rpc_client.rs

@@ -274,6 +274,10 @@ impl RpcClient {
         )
     }
 
+    pub fn get_snapshot_slot(&self) -> ClientResult<Slot> {
+        self.send(RpcRequest::GetSnapshotSlot, Value::Null)
+    }
+
     pub fn get_signature_status(
         &self,
         signature: &Signature,

client/src/rpc_custom_error.rs

@@ -11,6 +11,7 @@ pub const JSON_RPC_SERVER_ERROR_BLOCK_NOT_AVAILABLE: i64 = -32004;
 pub const JSON_RPC_SERVER_ERROR_NODE_UNHEALTHLY: i64 = -32005;
 pub const JSON_RPC_SERVER_ERROR_TRANSACTION_PRECOMPILE_VERIFICATION_FAILURE: i64 = -32006;
 pub const JSON_RPC_SERVER_ERROR_SLOT_SKIPPED: i64 = -32007;
+pub const JSON_RPC_SERVER_ERROR_NO_SNAPSHOT: i64 = -32008;
 
 pub enum RpcCustomError {
     BlockCleanedUp {
@@ -32,6 +33,7 @@ pub enum RpcCustomError {
     SlotSkipped {
         slot: Slot,
     },
+    NoSnapshot,
 }
 
 #[derive(Debug, Serialize, Deserialize)]
@@ -95,6 +97,11 @@ impl From<RpcCustomError> for Error {
                 ),
                 data: None,
             },
+            RpcCustomError::NoSnapshot => Self {
+                code: ErrorCode::ServerError(JSON_RPC_SERVER_ERROR_NO_SNAPSHOT),
+                message: "No snapshot".to_string(),
+                data: None,
+            },
         }
     }
 }

client/src/rpc_request.rs

@@ -35,6 +35,7 @@ pub enum RpcRequest {
     GetMultipleAccounts,
     GetProgramAccounts,
     GetRecentBlockhash,
+    GetSnapshotSlot,
     GetSignatureStatuses,
     GetSlot,
     GetSlotLeader,
@@ -91,6 +92,7 @@ impl fmt::Display for RpcRequest {
             RpcRequest::GetMultipleAccounts => "getMultipleAccounts",
             RpcRequest::GetProgramAccounts => "getProgramAccounts",
             RpcRequest::GetRecentBlockhash => "getRecentBlockhash",
+            RpcRequest::GetSnapshotSlot => "getSnapshotSlot",
             RpcRequest::GetSignatureStatuses => "getSignatureStatuses",
             RpcRequest::GetSlot => "getSlot",
             RpcRequest::GetSlotLeader => "getSlotLeader",

core/src/rpc.rs

@@ -41,9 +41,10 @@ use solana_runtime::{
     accounts::AccountAddressFilter,
     accounts_index::{AccountIndex, IndexKey},
     bank::Bank,
-    bank_forks::BankForks,
+    bank_forks::{BankForks, SnapshotConfig},
     commitment::{BlockCommitmentArray, BlockCommitmentCache, CommitmentSlots},
     inline_spl_token_v2_0::{SPL_TOKEN_ACCOUNT_MINT_OFFSET, SPL_TOKEN_ACCOUNT_OWNER_OFFSET},
+    snapshot_utils::get_highest_snapshot_archive_path,
 };
 use solana_sdk::{
     account::Account,
@@ -122,6 +123,7 @@ pub struct JsonRpcRequestProcessor {
     block_commitment_cache: Arc<RwLock<BlockCommitmentCache>>,
     blockstore: Arc<Blockstore>,
     config: JsonRpcConfig,
+    snapshot_config: Option<SnapshotConfig>,
     validator_exit: Arc<RwLock<Option<ValidatorExit>>>,
     health: Arc<RpcHealth>,
     cluster_info: Arc<ClusterInfo>,
@@ -199,6 +201,7 @@ impl JsonRpcRequestProcessor {
     #[allow(clippy::too_many_arguments)]
     pub fn new(
         config: JsonRpcConfig,
+        snapshot_config: Option<SnapshotConfig>,
         bank_forks: Arc<RwLock<BankForks>>,
         block_commitment_cache: Arc<RwLock<BlockCommitmentCache>>,
         blockstore: Arc<Blockstore>,
@@ -214,6 +217,7 @@ impl JsonRpcRequestProcessor {
         (
             Self {
                 config,
+                snapshot_config,
                 bank_forks,
                 block_commitment_cache,
                 blockstore,
@@ -246,6 +250,7 @@ impl JsonRpcRequestProcessor {
 
         Self {
             config: JsonRpcConfig::default(),
+            snapshot_config: None,
             bank_forks,
             block_commitment_cache: Arc::new(RwLock::new(BlockCommitmentCache::new(
                 HashMap::new(),
@@ -463,7 +468,7 @@ impl JsonRpcRequestProcessor {
         }
     }
 
-    fn get_slot(&self, commitment: Option<CommitmentConfig>) -> u64 {
+    fn get_slot(&self, commitment: Option<CommitmentConfig>) -> Slot {
         self.bank(commitment).slot()
     }
 
@@ -1799,6 +1804,9 @@ pub trait RpcSol {
         meta: Self::Metadata,
     ) -> Result<RpcResponse<RpcFeeRateGovernor>>;
 
+    #[rpc(meta, name = "getSnapshotSlot")]
+    fn get_snapshot_slot(&self, meta: Self::Metadata) -> Result<Slot>;
+
     #[rpc(meta, name = "getSignatureStatuses")]
     fn get_signature_statuses(
         &self,
@@ -1808,7 +1816,7 @@ pub trait RpcSol {
     ) -> Result<RpcResponse<Vec<Option<TransactionStatus>>>>;
 
     #[rpc(meta, name = "getSlot")]
-    fn get_slot(&self, meta: Self::Metadata, commitment: Option<CommitmentConfig>) -> Result<u64>;
+    fn get_slot(&self, meta: Self::Metadata, commitment: Option<CommitmentConfig>) -> Result<Slot>;
 
     #[rpc(meta, name = "getTransactionCount")]
     fn get_transaction_count(
@@ -2354,6 +2362,17 @@ impl RpcSol for RpcSolImpl {
         Ok(meta.get_signature_status(signature, commitment))
     }
 
+    fn get_snapshot_slot(&self, meta: Self::Metadata) -> Result<Slot> {
+        debug!("get_snapshot_slot rpc request received");
+
+        meta.snapshot_config
+            .and_then(|snapshot_config| {
+                get_highest_snapshot_archive_path(&snapshot_config.snapshot_package_output_path)
+                    .map(|(_, (slot, _, _))| slot)
+            })
+            .ok_or_else(|| RpcCustomError::NoSnapshot.into())
+    }
+
     fn get_signature_statuses(
         &self,
         meta: Self::Metadata,
@@ -2377,7 +2396,7 @@ impl RpcSol for RpcSolImpl {
         meta.get_signature_statuses(signatures, config)
     }
 
-    fn get_slot(&self, meta: Self::Metadata, commitment: Option<CommitmentConfig>) -> Result<u64> {
+    fn get_slot(&self, meta: Self::Metadata, commitment: Option<CommitmentConfig>) -> Result<Slot> {
         debug!("get_slot rpc request received");
         Ok(meta.get_slot(commitment))
     }
@@ -3080,6 +3099,7 @@ pub mod tests {
                 identity_pubkey: *pubkey,
                 ..JsonRpcConfig::default()
             },
+            None,
             bank_forks.clone(),
             block_commitment_cache.clone(),
             blockstore,
@@ -4480,6 +4500,7 @@ pub mod tests {
         let tpu_address = cluster_info.my_contact_info().tpu;
         let (meta, receiver) = JsonRpcRequestProcessor::new(
             JsonRpcConfig::default(),
+            None,
             bank_forks.clone(),
             block_commitment_cache,
             blockstore,
@@ -4676,6 +4697,7 @@ pub mod tests {
         let bank_forks = new_bank_forks().0;
         let (request_processor, receiver) = JsonRpcRequestProcessor::new(
             JsonRpcConfig::default(),
+            None,
             bank_forks.clone(),
             block_commitment_cache,
             blockstore,
@@ -4708,6 +4730,7 @@ pub mod tests {
         let tpu_address = cluster_info.my_contact_info().tpu;
         let (request_processor, receiver) = JsonRpcRequestProcessor::new(
             config,
+            None,
             bank_forks.clone(),
             block_commitment_cache,
             blockstore,
@@ -4799,6 +4822,7 @@ pub mod tests {
         let tpu_address = cluster_info.my_contact_info().tpu;
         let (request_processor, receiver) = JsonRpcRequestProcessor::new(
             config,
+            None,
             bank_forks.clone(),
             block_commitment_cache,
             blockstore,
@@ -6027,6 +6051,7 @@ pub mod tests {
 
         let (meta, _receiver) = JsonRpcRequestProcessor::new(
             JsonRpcConfig::default(),
+            None,
             bank_forks.clone(),
             block_commitment_cache,
             blockstore,

core/src/rpc_service.rs

@@ -329,6 +329,7 @@ impl JsonRpcService {
 
         let (request_processor, receiver) = JsonRpcRequestProcessor::new(
             config,
+            snapshot_config.clone(),
             bank_forks.clone(),
             block_commitment_cache,
             blockstore,

docs/src/developing/clients/jsonrpc-api.md

@@ -1968,6 +1968,38 @@ Result:
 }
 ```
 
+
+### getSnapshotSlot
+
+Returns the highest slot that the node has a snapshot for
+
+#### Parameters:
+
+None
+
+#### Results:
+
+- `<u64>` - Snapshot slot
+
+#### Example:
+
+Request:
+```bash
+curl http://localhost:8899 -X POST -H "Content-Type: application/json" -d '
+  {"jsonrpc":"2.0","id":1, "method":"getSnapshotSlot"}
+'
+```
+
+Result:
+```json
+{"jsonrpc":"2.0","result":100,"id":1}
+```
+
+Result when the node has no snapshot:
+```json
+{"jsonrpc":"2.0","error":{"code":-32008,"message":"No snapshot"},"id":1}
+```
+
 ### getSignatureStatuses
 
 Returns the statuses of a list of signatures. Unless the

validator/src/bin/solana-test-validator.rs

@@ -380,10 +380,7 @@ fn main() {
         }
 
         loop {
-            let snapshot_slot =
+            let snapshot_slot = rpc_client.get_snapshot_slot().ok();
-                solana_runtime::snapshot_utils::get_highest_snapshot_archive_path(&ledger_path)
-                    .map(|(_, (slot, _, _))| slot)
-                    .unwrap_or(0);
 
             for _i in 0..10 {
                 match get_validator_stats(&rpc_client, &identity) {
@@ -400,16 +397,25 @@ fn main() {
                         progress_bar.set_message(&format!(
                             "{:02}:{:02}:{:02} \
                             {}| \
-                            Processed Slot: {} | Confirmed Slot: {} | Finalized Slot: {} | Snapshot Slot: {} | \
+                            Processed Slot: {} | Confirmed Slot: {} | Finalized Slot: {} | \
+                            Snapshot Slot: {} | \
                             Transactions: {} | {}",
-                            uptime.num_hours(), uptime.num_minutes() % 60, uptime.num_seconds() % 60,
+                            uptime.num_hours(),
+                            uptime.num_minutes() % 60,
+                            uptime.num_seconds() % 60,
                             if health == "ok" {
                                 "".to_string()
                             } else {
                                 format!("| {} ", style(health).bold().red())
                             },
-                            processed_slot, confirmed_slot, finalized_slot, snapshot_slot,
+                            processed_slot,
-                            transaction_count, identity_balance
+                            confirmed_slot,
+                            finalized_slot,
+                            snapshot_slot
+                                .map(|s| s.to_string())
+                                .unwrap_or_else(|| "-".to_string()),
+                            transaction_count,
+                            identity_balance
                         ));
                     }
                     Err(err) => {