fix(rpc): move submit proof checks off async runtime

CHANGELOG.md

@@ -20,6 +20,7 @@
 - [BREAKING] Removed `CheckNullifiers` endpoint ([#2049](https://github.com/0xMiden/node/pull/2049)).
 - Replaced blocking-in-async operations in the validator, remote prover, and ntx-builder with `spawn_blocking` to avoid starving the Tokio runtime ([#2041](https://github.com/0xMiden/node/pull/2041)).
 - Replaced local store block proving with `spawn_blocking` to avoid starving the Tokio runtime ([#1976](https://github.com/0xMiden/node/issues/1976)).
+- Replaced blocking proof verification in RPC transaction submission endpoints with `spawn_blocking` to avoid starving the Tokio runtime ([#1976](https://github.com/0xMiden/node/issues/1976)).
 - Implemented persistent RocksDB backend for `AccountStateForest`, improving startup time ([#2020](https://github.com/0xMiden/node/pull/2020)).
 - [BREAKING] Replaced binding URL env vars and CLI flags with listen socket addresses ([#2054](https://github.com/0xMiden/node/pull/2054)).
 - [BREAKING] `BlockRange.block_to` is now required for all RPC endpoints ([#2056](https://github.com/0xMiden/node/pull/2056)).

crates/rpc/src/server/api.rs

@@ -27,6 +27,7 @@ use miden_node_utils::limiter::{
     QueryParamStorageMapKeyTotalLimit,
 };
 use miden_node_utils::lru_cache::LruCache;
+use miden_node_utils::spawn::spawn_blocking_in_current_span;
 use miden_node_utils::tracing::OpenTelemetrySpanExt;
 use miden_protocol::batch::{ProposedBatch, ProvenBatch};
 use miden_protocol::block::{BlockHeader, BlockNumber};
@@ -526,14 +527,20 @@ impl api_server::Api for RpcService {
             ));
         }
 
-        let tx_verifier = TransactionVerifier::new(MIN_PROOF_SECURITY_LEVEL);
-        tx_verifier.verify(&tx).map_err(|err| {
-            Status::invalid_argument(format!(
-                "Invalid proof for transaction {}: {}",
-                tx.id(),
-                err.as_report()
-            ))
-        })?;
+        let tx_id = tx.id();
+        spawn_blocking_in_current_span(move || {
+            TransactionVerifier::new(MIN_PROOF_SECURITY_LEVEL).verify(&tx).map_err(|err| {
+                Status::invalid_argument(format!(
+                    "Invalid proof for transaction {}: {}",
+                    tx_id,
+                    err.as_report()
+                ))
+            })
+        })
+        .await
+        .map_err(|err| {
+            Status::internal(format!("transaction proof verification task failed: {err}"))
+        })??;
 
         // Transaction inputs must be provided in order to allow for transaction re-execution via
         // the Validator.
@@ -613,11 +620,22 @@ impl api_server::Api for RpcService {
         //
         // Need to do this because ProvenBatch has no real kernel yet, so we can only
         // really check that the calculated proof matches the one given in the request.
-        let expected_proof = LocalBatchProver::new(MIN_PROOF_SECURITY_LEVEL)
-            .prove(proposed_batch.clone())
-            .map_err(|err| {
-                Status::invalid_argument(err.as_report_context("proposed block proof failed"))
-            })?;
+        let expected_proof = spawn_blocking_in_current_span({
+            let proposed_batch = proposed_batch.clone();
+            move || {
+                LocalBatchProver::new(MIN_PROOF_SECURITY_LEVEL).prove(proposed_batch).map_err(
+                    |err| {
+                        Status::invalid_argument(
+                            err.as_report_context("proposed block proof failed"),
+                        )
+                    },
+                )
+            }
+        })
+        .await
+        .map_err(|err| {
+            Status::internal(format!("batch proof verification task failed: {err}"))
+        })??;
 
         if expected_proof != proven_batch {
             return Err(Status::invalid_argument("batch proof did not match proposed batch"));