decrement connection counts

src/main.rs

@@ -17,12 +17,12 @@ const PARALLEL_REQUESTS: usize = 4;
 type RpcRateLimiter =
     RateLimiter<NotKeyed, InMemoryState, QuantaClock, NoOpMiddleware<QuantaInstant>>;
 
+type ConnectionsMap = DashMap<String, u32>;
+
 /// Load balance to the least-connection rpc
 struct BalancedRpcs {
     rpcs: RwLock<Vec<String>>,
-    connections: DashMap<String, u32>,
-    // TODO: what type? store with connections?
-    // ratelimits: RateLimiter<K, DashMapStateStore<K>, dyn governor::clock::Clock>,
+    connections: ConnectionsMap,
     ratelimits: DashMap<String, RpcRateLimiter>,
 }
 
@@ -95,7 +95,6 @@ impl BalancedRpcs {
             };
 
             // increment our connection counter
-            // TODO: need to change this to be an atomic counter!
             let mut connections = self.connections.get_mut(selected_rpc).unwrap();
             *connections += 1;
 
@@ -175,7 +174,10 @@ impl Web3ProxyState {
             // there are private rpcs configured and the request is eth_sendSignedTransaction. send to all private rpcs
             let upstream_servers = self.private_rpcs.get_upstream_servers().await;
 
-            if let Ok(result) = self.try_send_requests(upstream_servers, &json_body).await {
+            if let Ok(result) = self
+                .try_send_requests(upstream_servers, None, &json_body)
+                .await
+            {
                 return Ok(result);
             }
         } else {
@@ -184,7 +186,11 @@ impl Web3ProxyState {
                 if let Ok(upstream_server) = balanced_rpcs.get_upstream_server().await {
                     // TODO: capture any errors. at least log them
                     if let Ok(result) = self
-                        .try_send_requests(vec![upstream_server], &json_body)
+                        .try_send_requests(
+                            vec![upstream_server],
+                            Some(&balanced_rpcs.connections),
+                            &json_body,
+                        )
                         .await
                     {
                         return Ok(result);
@@ -201,6 +207,7 @@ impl Web3ProxyState {
     async fn try_send_requests(
         &self,
         upstream_servers: Vec<String>,
+        connections: Option<&ConnectionsMap>,
         json_body: &serde_json::Value,
     ) -> anyhow::Result<String> {
         // send the query to all the servers
@@ -209,8 +216,16 @@ impl Web3ProxyState {
                 let client = self.client.clone();
                 let json_body = json_body.clone();
                 tokio::spawn(async move {
-                    let resp = client.post(url).json(&json_body).send().await?;
-                    resp.text().await
+                    let resp = client
+                        .post(&url)
+                        .json(&json_body)
+                        .send()
+                        .await
+                        .map_err(|e| (url.clone(), e))?;
+                    resp.text()
+                        .await
+                        .map(|t| (url.clone(), t))
+                        .map_err(|e| (url, e))
                 })
             })
             .buffer_unordered(PARALLEL_REQUESTS);
@@ -220,12 +235,21 @@ impl Web3ProxyState {
 
         while let Some(b) = bodies.next().await {
             // TODO: reduce connection counter
+
             match b {
-                Ok(Ok(b)) => {
+                Ok(Ok((url, b))) => {
+                    if let Some(connections) = connections {
+                        *connections.get_mut(&url).unwrap() -= 1;
+                    }
+
                     // TODO: if "no block with that header", skip this response (maybe retry)
                     oks.push(b);
                 }
-                Ok(Err(e)) => {
+                Ok(Err((url, e))) => {
+                    if let Some(connections) = connections {
+                        *connections.get_mut(&url).unwrap() -= 1;
+                    }
+
                     // TODO: better errors
                     eprintln!("Got a reqwest::Error: {}", e);
                     errs.push(anyhow::anyhow!("Got a reqwest::Error"));