feat: tracing permits

Author: prestwich

crates/rpc/src/ctx/full.rs

@@ -13,6 +13,7 @@ use signet_node_types::Pnt;
 use signet_tx_cache::client::TxCache;
 use signet_types::constants::SignetSystemConstants;
 use std::sync::Arc;
+use tokio::sync::{AcquireError, OwnedSemaphorePermit, Semaphore};
 use trevm::helpers::Ctx;
 
 /// State location when instantiating an EVM instance.
@@ -126,6 +127,12 @@ where
     }
 }
 
+/// Shared context between all RPC handlers.
+#[derive(Debug)]
+struct SharedContext {
+    tracing_semaphores: Arc<Semaphore>,
+}
+
 /// Inner context for [`RpcCtx`].
 #[derive(Debug)]
 pub struct RpcCtxInner<Host, Signet>
@@ -135,6 +142,8 @@ where
 {
     host: Host,
     signet: SignetCtx<Signet>,
+
+    shared: SharedContext,
 }
 
 impl<Host, Signet> RpcCtxInner<Host, Signet>
@@ -154,8 +163,18 @@ where
     where
         Tasks: TaskSpawner + Clone + 'static,
     {
-        SignetCtx::new(constants, factory, eth_config, tx_cache, spawner)
-            .map(|signet| Self { host, signet })
+        SignetCtx::new(constants, factory, eth_config, tx_cache, spawner).map(|signet| Self {
+            host,
+            signet,
+            shared: SharedContext {
+                tracing_semaphores: Semaphore::new(eth_config.max_tracing_requests).into(),
+            },
+        })
+    }
+
+    /// Acquire a permit for tracing.
+    pub async fn acquire_tracing_permit(&self) -> Result<OwnedSemaphorePermit, AcquireError> {
+        self.shared.tracing_semaphores.clone().acquire_owned().await
     }
 
     pub const fn host(&self) -> &Host {

crates/rpc/src/debug/endpoints.rs

@@ -38,6 +38,12 @@ where
     Host: FullNodeComponents,
     Signet: Pnt,
 {
+    let _permit = response_tri!(
+        ctx.acquire_tracing_permit()
+            .await
+            .map_err(|_| DebugError::rpc_error("Failed to acquire tracing permit".into()))
+    );
+
     let id = id.into();
     let span = tracing::debug_span!("traceBlock", ?id, tracer = ?opts.as_ref().and_then(|o| o.tracer.as_ref()));
 
@@ -101,6 +107,12 @@ where
     Host: FullNodeComponents,
     Signet: Pnt,
 {
+    let _permit = response_tri!(
+        ctx.acquire_tracing_permit()
+            .await
+            .map_err(|_| DebugError::rpc_error("Failed to acquire tracing permit".into()))
+    );
+
     let span = tracing::debug_span!("traceTransaction", %tx_hash, tracer = ?opts.as_ref().and_then(|o| o.tracer.as_ref()));
 
     let fut = async move {