Merge pull request #302 from semiotic-ai/fix/grpc_limits

fix: add layer to set concurrent limits for gRPC

Author: neithanmo

tap_aggregator/Cargo.toml

@@ -32,7 +32,7 @@ tap_graph.workspace = true
 thegraph-core = { workspace = true, features = ["alloy-eip712"] }
 tokio.workspace = true
 tonic.workspace = true
-tower.workspace = true
+tower = { workspace = true, features = ["util", "steer", "limit"] }
 tracing-subscriber.workspace = true
 
 [build-dependencies]

tap_aggregator/src/server.rs

@@ -378,8 +378,14 @@ pub async fn run_server(
 
     let grpc_service = create_grpc_service(rpc_impl)?;
 
+    let grpc_router = Router::new()
+        .layer(tower::limit::ConcurrencyLimitLayer::new(
+            max_concurrent_connections as usize,
+        ))
+        .merge(grpc_service.into_axum_router());
+
     let service = tower::steer::Steer::new(
-        [json_rpc_router, grpc_service.into_axum_router()],
+        [json_rpc_router, grpc_router],
         |req: &hyper::Request<_>, _services: &[_]| {
             if req
                 .headers()