dynamic_forward_proxy: DNS Cache circuit breaker

source/extensions/common/dynamic_forward_proxy/dns_cache.h

@@ -177,10 +177,9 @@ class DnsCache {
   virtual absl::flat_hash_map<std::string, DnsHostInfoSharedPtr> hosts() PURE;
 
   /**
-   * Handle dns request
-   * @param route_entry resolved route entry.
-   * @param cluster_info destination cluster info.
-   * @return Resource limit which describes about pending requests.
+   * Check if we can do DNS Request.
+   * @param pending_request pending request resource limit
+   * @return RAII Pointer for circuit breakers
    */
   virtual Upstream::ResourceAutoIncDecPtr
   canCreateDnsRequest(absl::optional<std::reference_wrapper<ResourceLimit>> pending_request) PURE;

source/extensions/common/dynamic_forward_proxy/dns_cache_impl.cc

@@ -79,12 +79,11 @@ DnsCacheImpl::loadDnsCacheEntry(absl::string_view host, uint16_t default_port,
 
 Upstream::ResourceAutoIncDecPtr DnsCacheImpl::canCreateDnsRequest(
     absl::optional<std::reference_wrapper<ResourceLimit>> pending_requests) {
-  auto use_cluster_cache_circuit_breaker = pending_requests.has_value();
-  auto& current_pending_requests = use_cluster_cache_circuit_breaker
-                                       ? pending_requests->get()
-                                       : resource_manager_.pendingRequests();
+  const auto has_pending_requests = pending_requests.has_value();
+  auto& current_pending_requests =
+      has_pending_requests ? pending_requests->get() : resource_manager_.pendingRequests();
   if (!current_pending_requests.canCreate()) {
-    if (!use_cluster_cache_circuit_breaker) {
+    if (!has_pending_requests) {
       stats_.dns_rq_pending_overflow_.inc();
     }
     return nullptr;

source/extensions/filters/http/dynamic_forward_proxy/proxy_filter.cc

@@ -58,15 +58,13 @@ Http::FilterHeadersStatus ProxyFilter::decodeHeaders(Http::RequestHeaderMap& hea
   const bool should_use_dns_cache_circuit_breakers =
       Runtime::runtimeFeatureEnabled("envoy.reloadable_features.enable_dns_cache_circuit_breakers");
 
-  auto circuit_breaker_raii_ptr = config_->cache().canCreateDnsRequest(
+  circuit_breaker_ = config_->cache().canCreateDnsRequest(
       !should_use_dns_cache_circuit_breakers
           ? absl::make_optional(std::reference_wrapper<ResourceLimit>(
                 cluster_info_->resourceManager(route_entry->priority()).pendingRequests()))
           : absl::nullopt);
 
-  if (circuit_breaker_raii_ptr != nullptr) {
-    circuit_breaker_ = std::move(circuit_breaker_raii_ptr);
-  } else {
+  if (circuit_breaker_ == nullptr) {
     if (!should_use_dns_cache_circuit_breakers) {
       cluster_info_->stats().upstream_rq_pending_overflow_.inc();
     }