Merge pull request #19489 from apolcyn/fix_ares_throttle

Fix DNS resolver cooldown

CMakeLists.txt

@@ -275,7 +275,8 @@ add_dependencies(buildtests_c compression_test)
 add_dependencies(buildtests_c concurrent_connectivity_test)
 add_dependencies(buildtests_c connection_refused_test)
 add_dependencies(buildtests_c dns_resolver_connectivity_test)
-add_dependencies(buildtests_c dns_resolver_cooldown_test)
+add_dependencies(buildtests_c dns_resolver_cooldown_using_ares_resolver_test)
+add_dependencies(buildtests_c dns_resolver_cooldown_using_native_resolver_test)
 add_dependencies(buildtests_c dns_resolver_test)
 if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
 add_dependencies(buildtests_c dualstack_socket_test)
@@ -6877,12 +6878,12 @@ target_link_libraries(dns_resolver_connectivity_test
 endif (gRPC_BUILD_TESTS)
 if (gRPC_BUILD_TESTS)
 
-add_executable(dns_resolver_cooldown_test
+add_executable(dns_resolver_cooldown_using_ares_resolver_test
   test/core/client_channel/resolvers/dns_resolver_cooldown_test.cc
 )
 
 
-target_include_directories(dns_resolver_cooldown_test
+target_include_directories(dns_resolver_cooldown_using_ares_resolver_test
   PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
   PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include
   PRIVATE ${_gRPC_SSL_INCLUDE_DIR}
@@ -6895,7 +6896,7 @@ target_include_directories(dns_resolver_cooldown_test
   PRIVATE ${_gRPC_NANOPB_INCLUDE_DIR}
 )
 
-target_link_libraries(dns_resolver_cooldown_test
+target_link_libraries(dns_resolver_cooldown_using_ares_resolver_test
   ${_gRPC_ALLTARGETS_LIBRARIES}
   grpc_test_util
   grpc
@@ -6904,8 +6905,42 @@ target_link_libraries(dns_resolver_cooldown_test
 
   # avoid dependency on libstdc++
   if (_gRPC_CORE_NOSTDCXX_FLAGS)
-    set_target_properties(dns_resolver_cooldown_test PROPERTIES LINKER_LANGUAGE C)
-    target_compile_options(dns_resolver_cooldown_test PRIVATE $<$<COMPILE_LANGUAGE:CXX>:${_gRPC_CORE_NOSTDCXX_FLAGS}>)
+    set_target_properties(dns_resolver_cooldown_using_ares_resolver_test PROPERTIES LINKER_LANGUAGE C)
+    target_compile_options(dns_resolver_cooldown_using_ares_resolver_test PRIVATE $<$<COMPILE_LANGUAGE:CXX>:${_gRPC_CORE_NOSTDCXX_FLAGS}>)
+  endif()
+
+endif (gRPC_BUILD_TESTS)
+if (gRPC_BUILD_TESTS)
+
+add_executable(dns_resolver_cooldown_using_native_resolver_test
+  test/core/client_channel/resolvers/dns_resolver_cooldown_test.cc
+)
+
+
+target_include_directories(dns_resolver_cooldown_using_native_resolver_test
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include
+  PRIVATE ${_gRPC_SSL_INCLUDE_DIR}
+  PRIVATE ${_gRPC_PROTOBUF_INCLUDE_DIR}
+  PRIVATE ${_gRPC_ZLIB_INCLUDE_DIR}
+  PRIVATE ${_gRPC_BENCHMARK_INCLUDE_DIR}
+  PRIVATE ${_gRPC_CARES_INCLUDE_DIR}
+  PRIVATE ${_gRPC_GFLAGS_INCLUDE_DIR}
+  PRIVATE ${_gRPC_ADDRESS_SORTING_INCLUDE_DIR}
+  PRIVATE ${_gRPC_NANOPB_INCLUDE_DIR}
+)
+
+target_link_libraries(dns_resolver_cooldown_using_native_resolver_test
+  ${_gRPC_ALLTARGETS_LIBRARIES}
+  grpc_test_util
+  grpc
+  gpr
+)
+
+  # avoid dependency on libstdc++
+  if (_gRPC_CORE_NOSTDCXX_FLAGS)
+    set_target_properties(dns_resolver_cooldown_using_native_resolver_test PROPERTIES LINKER_LANGUAGE C)
+    target_compile_options(dns_resolver_cooldown_using_native_resolver_test PRIVATE $<$<COMPILE_LANGUAGE:CXX>:${_gRPC_CORE_NOSTDCXX_FLAGS}>)
   endif()
 
 endif (gRPC_BUILD_TESTS)

Makefile

@@ -1015,7 +1015,8 @@ compression_test: $(BINDIR)/$(CONFIG)/compression_test
 concurrent_connectivity_test: $(BINDIR)/$(CONFIG)/concurrent_connectivity_test
 connection_refused_test: $(BINDIR)/$(CONFIG)/connection_refused_test
 dns_resolver_connectivity_test: $(BINDIR)/$(CONFIG)/dns_resolver_connectivity_test
-dns_resolver_cooldown_test: $(BINDIR)/$(CONFIG)/dns_resolver_cooldown_test
+dns_resolver_cooldown_using_ares_resolver_test: $(BINDIR)/$(CONFIG)/dns_resolver_cooldown_using_ares_resolver_test
+dns_resolver_cooldown_using_native_resolver_test: $(BINDIR)/$(CONFIG)/dns_resolver_cooldown_using_native_resolver_test
 dns_resolver_test: $(BINDIR)/$(CONFIG)/dns_resolver_test
 dualstack_socket_test: $(BINDIR)/$(CONFIG)/dualstack_socket_test
 endpoint_pair_test: $(BINDIR)/$(CONFIG)/endpoint_pair_test
@@ -1446,7 +1447,8 @@ buildtests_c: privatelibs_c \
   $(BINDIR)/$(CONFIG)/concurrent_connectivity_test \
   $(BINDIR)/$(CONFIG)/connection_refused_test \
   $(BINDIR)/$(CONFIG)/dns_resolver_connectivity_test \
-  $(BINDIR)/$(CONFIG)/dns_resolver_cooldown_test \
+  $(BINDIR)/$(CONFIG)/dns_resolver_cooldown_using_ares_resolver_test \
+  $(BINDIR)/$(CONFIG)/dns_resolver_cooldown_using_native_resolver_test \
   $(BINDIR)/$(CONFIG)/dns_resolver_test \
   $(BINDIR)/$(CONFIG)/dualstack_socket_test \
   $(BINDIR)/$(CONFIG)/endpoint_pair_test \
@@ -1983,8 +1985,10 @@ test_c: buildtests_c
 	$(Q) $(BINDIR)/$(CONFIG)/connection_refused_test || ( echo test connection_refused_test failed ; exit 1 )
 	$(E) "[RUN]     Testing dns_resolver_connectivity_test"
 	$(Q) $(BINDIR)/$(CONFIG)/dns_resolver_connectivity_test || ( echo test dns_resolver_connectivity_test failed ; exit 1 )
-	$(E) "[RUN]     Testing dns_resolver_cooldown_test"
-	$(Q) $(BINDIR)/$(CONFIG)/dns_resolver_cooldown_test || ( echo test dns_resolver_cooldown_test failed ; exit 1 )
+	$(E) "[RUN]     Testing dns_resolver_cooldown_using_ares_resolver_test"
+	$(Q) $(BINDIR)/$(CONFIG)/dns_resolver_cooldown_using_ares_resolver_test || ( echo test dns_resolver_cooldown_using_ares_resolver_test failed ; exit 1 )
+	$(E) "[RUN]     Testing dns_resolver_cooldown_using_native_resolver_test"
+	$(Q) $(BINDIR)/$(CONFIG)/dns_resolver_cooldown_using_native_resolver_test || ( echo test dns_resolver_cooldown_using_native_resolver_test failed ; exit 1 )
 	$(E) "[RUN]     Testing dns_resolver_test"
 	$(Q) $(BINDIR)/$(CONFIG)/dns_resolver_test || ( echo test dns_resolver_test failed ; exit 1 )
 	$(E) "[RUN]     Testing dualstack_socket_test"
@@ -9641,34 +9645,66 @@ endif
 endif
 
 
-DNS_RESOLVER_COOLDOWN_TEST_SRC = \
+DNS_RESOLVER_COOLDOWN_USING_ARES_RESOLVER_TEST_SRC = \
     test/core/client_channel/resolvers/dns_resolver_cooldown_test.cc \
 
-DNS_RESOLVER_COOLDOWN_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(DNS_RESOLVER_COOLDOWN_TEST_SRC))))
+DNS_RESOLVER_COOLDOWN_USING_ARES_RESOLVER_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(DNS_RESOLVER_COOLDOWN_USING_ARES_RESOLVER_TEST_SRC))))
 ifeq ($(NO_SECURE),true)
 
 # You can't build secure targets if you don't have OpenSSL.
 
-$(BINDIR)/$(CONFIG)/dns_resolver_cooldown_test: openssl_dep_error
+$(BINDIR)/$(CONFIG)/dns_resolver_cooldown_using_ares_resolver_test: openssl_dep_error
 
 else
 
 
 
-$(BINDIR)/$(CONFIG)/dns_resolver_cooldown_test: $(DNS_RESOLVER_COOLDOWN_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr.a
+$(BINDIR)/$(CONFIG)/dns_resolver_cooldown_using_ares_resolver_test: $(DNS_RESOLVER_COOLDOWN_USING_ARES_RESOLVER_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr.a
 	$(E) "[LD]      Linking $@"
 	$(Q) mkdir -p `dirname $@`
-	$(Q) $(LD) $(LDFLAGS) $(DNS_RESOLVER_COOLDOWN_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBS) $(LDLIBS_SECURE) -o $(BINDIR)/$(CONFIG)/dns_resolver_cooldown_test
+	$(Q) $(LD) $(LDFLAGS) $(DNS_RESOLVER_COOLDOWN_USING_ARES_RESOLVER_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBS) $(LDLIBS_SECURE) -o $(BINDIR)/$(CONFIG)/dns_resolver_cooldown_using_ares_resolver_test
 
 endif
 
 $(OBJDIR)/$(CONFIG)/test/core/client_channel/resolvers/dns_resolver_cooldown_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr.a
 
-deps_dns_resolver_cooldown_test: $(DNS_RESOLVER_COOLDOWN_TEST_OBJS:.o=.dep)
+deps_dns_resolver_cooldown_using_ares_resolver_test: $(DNS_RESOLVER_COOLDOWN_USING_ARES_RESOLVER_TEST_OBJS:.o=.dep)
 
 ifneq ($(NO_SECURE),true)
 ifneq ($(NO_DEPS),true)
--include $(DNS_RESOLVER_COOLDOWN_TEST_OBJS:.o=.dep)
+-include $(DNS_RESOLVER_COOLDOWN_USING_ARES_RESOLVER_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
+DNS_RESOLVER_COOLDOWN_USING_NATIVE_RESOLVER_TEST_SRC = \
+    test/core/client_channel/resolvers/dns_resolver_cooldown_test.cc \
+
+DNS_RESOLVER_COOLDOWN_USING_NATIVE_RESOLVER_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(DNS_RESOLVER_COOLDOWN_USING_NATIVE_RESOLVER_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/dns_resolver_cooldown_using_native_resolver_test: openssl_dep_error
+
+else
+
+
+
+$(BINDIR)/$(CONFIG)/dns_resolver_cooldown_using_native_resolver_test: $(DNS_RESOLVER_COOLDOWN_USING_NATIVE_RESOLVER_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LD) $(LDFLAGS) $(DNS_RESOLVER_COOLDOWN_USING_NATIVE_RESOLVER_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBS) $(LDLIBS_SECURE) -o $(BINDIR)/$(CONFIG)/dns_resolver_cooldown_using_native_resolver_test
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/core/client_channel/resolvers/dns_resolver_cooldown_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_dns_resolver_cooldown_using_native_resolver_test: $(DNS_RESOLVER_COOLDOWN_USING_NATIVE_RESOLVER_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(DNS_RESOLVER_COOLDOWN_USING_NATIVE_RESOLVER_TEST_OBJS:.o=.dep)
 endif
 endif
 

build.yaml

@@ -2400,7 +2400,7 @@ targets:
   - gpr
   exclude_iomgrs:
   - uv
-- name: dns_resolver_cooldown_test
+- name: dns_resolver_cooldown_using_ares_resolver_test
   build: test
   language: c
   src:
@@ -2409,6 +2409,19 @@ targets:
   - grpc_test_util
   - grpc
   - gpr
+  args:
+  - --resolver=ares
+- name: dns_resolver_cooldown_using_native_resolver_test
+  build: test
+  language: c
+  src:
+  - test/core/client_channel/resolvers/dns_resolver_cooldown_test.cc
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr
+  args:
+  - --resolver=native
 - name: dns_resolver_test
   build: test
   language: c

src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc

@@ -401,7 +401,8 @@ void AresDnsResolver::MaybeStartResolvingLocked() {
       // new closure API is done, find a way to track this ref with the timer
       // callback as part of the type system.
       Ref(DEBUG_LOCATION, "next_resolution_timer_cooldown").release();
-      grpc_timer_init(&next_resolution_timer_, ms_until_next_resolution,
+      grpc_timer_init(&next_resolution_timer_,
+                      ExecCtx::Get()->Now() + ms_until_next_resolution,
                       &on_next_resolution_);
       return;
     }

src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc

@@ -230,7 +230,8 @@ void NativeDnsResolver::MaybeStartResolvingLocked() {
       // new closure API is done, find a way to track this ref with the timer
       // callback as part of the type system.
       Ref(DEBUG_LOCATION, "next_resolution_timer_cooldown").release();
-      grpc_timer_init(&next_resolution_timer_, ms_until_next_resolution,
+      grpc_timer_init(&next_resolution_timer_,
+                      ExecCtx::Get()->Now() + ms_until_next_resolution,
                       &on_next_resolution_);
       return;
     }

test/core/client_channel/resolvers/BUILD

@@ -19,9 +19,26 @@ grpc_package(name = "test/core/client_channel_resolvers")
 licenses(["notice"])  # Apache v2
 
 grpc_cc_test(
-    name = "dns_resolver_connectivity_test",
+    name = "dns_resolver_connectivity_using_ares_resolver_test",
     srcs = ["dns_resolver_connectivity_test.cc"],
     language = "C++",
+    args = [
+        "--resolver=ares",
+    ],
+    deps = [
+        "//:gpr",
+        "//:grpc",
+        "//test/core/util:grpc_test_util",
+    ],
+)
+
+grpc_cc_test(
+    name = "dns_resolver_connectivity_using_native_resolver_test",
+    srcs = ["dns_resolver_connectivity_test.cc"],
+    language = "C++",
+    args = [
+        "--resolver=native",
+    ],
     deps = [
         "//:gpr",
         "//:grpc",

test/core/client_channel/resolvers/dns_resolver_cooldown_test.cc

@@ -101,12 +101,16 @@ static grpc_ares_request* test_dns_lookup_ares_locked(
       addresses, check_grpclb, service_config_json, query_timeout_ms, combiner);
   ++g_resolution_count;
   static grpc_millis last_resolution_time = 0;
+  grpc_millis now =
+      grpc_timespec_to_millis_round_up(gpr_now(GPR_CLOCK_MONOTONIC));
+  gpr_log(GPR_DEBUG,
+          "last_resolution_time:%" PRId64 " now:%" PRId64
+          " min_time_between:%d",
+          last_resolution_time, now, kMinResolutionPeriodForCheckMs);
   if (last_resolution_time == 0) {
     last_resolution_time =
         grpc_timespec_to_millis_round_up(gpr_now(GPR_CLOCK_MONOTONIC));
   } else {
-    grpc_millis now =
-        grpc_timespec_to_millis_round_up(gpr_now(GPR_CLOCK_MONOTONIC));
     GPR_ASSERT(now - last_resolution_time >= kMinResolutionPeriodForCheckMs);
     last_resolution_time = now;
   }
@@ -212,19 +216,46 @@ struct OnResolutionCallbackArg {
 // Set to true by the last callback in the resolution chain.
 static bool g_all_callbacks_invoked;
 
+// It's interesting to run a few rounds of this test because as
+// we run more rounds, the base starting time
+// (i.e. ExecCtx g_start_time) gets further and further away
+// from "Now()". Thus the more rounds ran, the more highlighted the
+// difference is between absolute and relative times values.
+static void on_fourth_resolution(OnResolutionCallbackArg* cb_arg) {
+  gpr_log(GPR_INFO, "4th: g_resolution_count: %d", g_resolution_count);
+  GPR_ASSERT(g_resolution_count == 4);
+  cb_arg->resolver.reset();
+  gpr_atm_rel_store(&g_iomgr_args.done_atm, 1);
+  gpr_mu_lock(g_iomgr_args.mu);
+  GRPC_LOG_IF_ERROR("pollset_kick",
+                    grpc_pollset_kick(g_iomgr_args.pollset, nullptr));
+  gpr_mu_unlock(g_iomgr_args.mu);
+  grpc_core::Delete(cb_arg);
+  g_all_callbacks_invoked = true;
+}
+
+static void on_third_resolution(OnResolutionCallbackArg* cb_arg) {
+  gpr_log(GPR_INFO, "3rd: g_resolution_count: %d", g_resolution_count);
+  GPR_ASSERT(g_resolution_count == 3);
+  cb_arg->result_handler->SetCallback(on_fourth_resolution, cb_arg);
+  cb_arg->resolver->RequestReresolutionLocked();
+  gpr_mu_lock(g_iomgr_args.mu);
+  GRPC_LOG_IF_ERROR("pollset_kick",
+                    grpc_pollset_kick(g_iomgr_args.pollset, nullptr));
+  gpr_mu_unlock(g_iomgr_args.mu);
+}
+
 static void on_second_resolution(OnResolutionCallbackArg* cb_arg) {
   gpr_log(GPR_INFO, "2nd: g_resolution_count: %d", g_resolution_count);
   // The resolution callback was not invoked until new data was
   // available, which was delayed until after the cooldown period.
   GPR_ASSERT(g_resolution_count == 2);
-  cb_arg->resolver.reset();
-  gpr_atm_rel_store(&g_iomgr_args.done_atm, 1);
+  cb_arg->result_handler->SetCallback(on_third_resolution, cb_arg);
+  cb_arg->resolver->RequestReresolutionLocked();
   gpr_mu_lock(g_iomgr_args.mu);
   GRPC_LOG_IF_ERROR("pollset_kick",
                     grpc_pollset_kick(g_iomgr_args.pollset, nullptr));
   gpr_mu_unlock(g_iomgr_args.mu);
-  grpc_core::Delete(cb_arg);
-  g_all_callbacks_invoked = true;
 }
 
 static void on_first_resolution(OnResolutionCallbackArg* cb_arg) {
@@ -243,9 +274,7 @@ static void on_first_resolution(OnResolutionCallbackArg* cb_arg) {
 static void start_test_under_combiner(void* arg, grpc_error* error) {
   OnResolutionCallbackArg* res_cb_arg =
       static_cast<OnResolutionCallbackArg*>(arg);
-
   res_cb_arg->result_handler = grpc_core::New<ResultHandler>();
-
   grpc_core::ResolverFactory* factory =
       grpc_core::ResolverRegistry::LookupResolverFactory("dns");
   grpc_uri* uri = grpc_uri_parse(res_cb_arg->uri_str, 0);
@@ -300,7 +329,6 @@ int main(int argc, char** argv) {
   grpc_set_resolver_impl(&test_resolver);
 
   test_cooldown();
-
   {
     grpc_core::ExecCtx exec_ctx;
     GRPC_COMBINER_UNREF(g_combiner, "test");

tools/run_tests/generated/sources_and_headers.json

@@ -392,7 +392,23 @@
     "headers": [], 
     "is_filegroup": false, 
     "language": "c", 
-    "name": "dns_resolver_cooldown_test", 
+    "name": "dns_resolver_cooldown_using_ares_resolver_test", 
+    "src": [
+      "test/core/client_channel/resolvers/dns_resolver_cooldown_test.cc"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
+  {
+    "deps": [
+      "gpr", 
+      "grpc", 
+      "grpc_test_util"
+    ], 
+    "headers": [], 
+    "is_filegroup": false, 
+    "language": "c", 
+    "name": "dns_resolver_cooldown_using_native_resolver_test", 
     "src": [
       "test/core/client_channel/resolvers/dns_resolver_cooldown_test.cc"
     ], 

tools/run_tests/generated/tests.json

@@ -484,7 +484,35 @@
     "uses_polling": true
   }, 
   {
-    "args": [], 
+    "args": [
+      "--resolver=ares"
+    ], 
+    "benchmark": false, 
+    "ci_platforms": [
+      "linux", 
+      "mac", 
+      "posix", 
+      "windows"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "gtest": false, 
+    "language": "c", 
+    "name": "dns_resolver_cooldown_using_ares_resolver_test", 
+    "platforms": [
+      "linux", 
+      "mac", 
+      "posix", 
+      "windows"
+    ], 
+    "uses_polling": true
+  }, 
+  {
+    "args": [
+      "--resolver=native"
+    ], 
     "benchmark": false, 
     "ci_platforms": [
       "linux", 
@@ -498,7 +526,7 @@
     "flaky": false, 
     "gtest": false, 
     "language": "c", 
-    "name": "dns_resolver_cooldown_test", 
+    "name": "dns_resolver_cooldown_using_native_resolver_test", 
     "platforms": [
       "linux", 
       "mac",