explorer-api: add pending field to port check response

explorer-api/src/ping/http.rs

@@ -25,6 +25,7 @@ pub(crate) async fn index(
         Some(cache_value) => {
             trace!("Returning cached value for {}", pubkey);
             Some(Json(PingResponse {
+                pending: cache_value.pending,
                 ports: cache_value.ports,
             }))
         }
@@ -33,11 +34,16 @@ pub(crate) async fn index(
 
             match state.inner.get_mix_node(pubkey).await {
                 Some(bond) => {
-                    let ports = port_check(&bond).await;
+                    // set status to pending, so that any HTTP requests are pending
+                    state.inner.ping_cache.set_pending(pubkey).await;
 
+                    // do the check
+                    let ports = Some(port_check(&bond).await);
                     trace!("Tested mix node {}: {:?}", pubkey, ports);
-
-                    let response = PingResponse { ports };
+                    let response = PingResponse {
+                        ports,
+                        pending: false,
+                    };
 
                     // cache for 1 min
                     trace!("Caching value for {}", pubkey);

explorer-api/src/ping/models.rs

@@ -8,7 +8,8 @@ use tokio::sync::RwLock;
 
 pub(crate) type PingCache = HashMap<String, PingCacheItem>;
 
-const CACHE_TTL: Duration = Duration::from_secs(60 * 60); // 1 hour
+const PING_TTL: Duration = Duration::from_secs(60 * 5); // 5 mins, before port check will be re-tried (only while pending)
+const CACHE_TTL: Duration = Duration::from_secs(60 * 60); // 1 hour, to cache result from port check
 
 #[derive(Clone)]
 pub(crate) struct ThreadsafePingCache {
@@ -28,15 +29,36 @@ impl ThreadsafePingCache {
             .await
             .get(identity_key)
             .filter(|cache_item| cache_item.valid_until > SystemTime::now())
-            .map(|cache_item| PingResponse {
-                ports: cache_item.ports.clone(),
+            .map(|cache_item| {
+                if cache_item.pending {
+                    return PingResponse {
+                        pending: true,
+                        ports: None,
+                    };
+                }
+                PingResponse {
+                    pending: false,
+                    ports: cache_item.ports.clone(),
+                }
             })
     }
 
+    pub(crate) async fn set_pending(&self, identity_key: &str) {
+        self.inner.write().await.insert(
+            identity_key.to_string(),
+            PingCacheItem {
+                pending: true,
+                valid_until: SystemTime::now() + PING_TTL,
+                ports: None,
+            },
+        );
+    }
+
     pub(crate) async fn set(&self, identity_key: &str, item: PingResponse) {
         self.inner.write().await.insert(
             identity_key.to_string(),
             PingCacheItem {
+                pending: false,
                 valid_until: SystemTime::now() + CACHE_TTL,
                 ports: item.ports,
             },
@@ -46,10 +68,12 @@ impl ThreadsafePingCache {
 
 #[derive(Deserialize, Serialize, JsonSchema, Clone)]
 pub(crate) struct PingResponse {
-    pub(crate) ports: HashMap<u16, bool>,
+    pub(crate) pending: bool,
+    pub(crate) ports: Option<HashMap<u16, bool>>,
 }
 
 pub(crate) struct PingCacheItem {
-    pub(crate) ports: HashMap<u16, bool>,
+    pub(crate) pending: bool,
+    pub(crate) ports: Option<HashMap<u16, bool>>,
     pub(crate) valid_until: std::time::SystemTime,
 }