[keepalive] Allow server side keepalive_permit_without_calls setting to be overridden (#33917)

Need the ability to override server-side keepalive permit without calls
default without affecting client-side settings.
<!--

If you know who should review your pull request, please assign it to
that
person, otherwise the pull request would get assigned randomly.

If your pull request is for a specific language, please add the
appropriate
lang label.

-->

src/core/ext/transport/chttp2/transport/chttp2_transport.cc

@@ -398,16 +398,18 @@ static void read_channel_args(grpc_chttp2_transport* t,
       channel_args.GetDurationFromIntMillis(GRPC_ARG_KEEPALIVE_TIMEOUT_MS)
           .value_or(t->is_client ? g_default_client_keepalive_timeout
                                  : g_default_server_keepalive_timeout));
-  if (grpc_core::IsKeepaliveFixEnabled()) {
+  if (t->is_client) {
     t->keepalive_permit_without_calls =
         channel_args.GetBool(GRPC_ARG_KEEPALIVE_PERMIT_WITHOUT_CALLS)
-            .value_or(t->is_client
+            .value_or(grpc_core::IsKeepaliveFixEnabled()
                           ? g_default_client_keepalive_permit_without_calls
-                          : g_default_server_keepalive_permit_without_calls);
+                          : false);
   } else {
     t->keepalive_permit_without_calls =
         channel_args.GetBool(GRPC_ARG_KEEPALIVE_PERMIT_WITHOUT_CALLS)
-            .value_or(false);
+            .value_or(grpc_core::IsKeepaliveServerFixEnabled()
+                          ? g_default_server_keepalive_permit_without_calls
+                          : false);
   }
 
   // Only send the prefered rx frame size http2 setting if we are instructed

src/core/lib/experiments/experiments.cc

@@ -97,6 +97,10 @@ const char* const description_keepalive_fix =
     "Allows overriding keepalive_permit_without_calls. Refer "
     "https://github.com/grpc/grpc/pull/33428 for more information.";
 const char* const additional_constraints_keepalive_fix = "{}";
+const char* const description_keepalive_server_fix =
+    "Allows overriding keepalive_permit_without_calls for servers. Refer "
+    "https://github.com/grpc/grpc/pull/33917 for more information.";
+const char* const additional_constraints_keepalive_server_fix = "{}";
 #ifdef NDEBUG
 const bool kDefaultForDebugOnly = false;
 #else
@@ -152,6 +156,8 @@ const ExperimentMetadata g_experiment_metadata[] = {
      additional_constraints_unique_metadata_strings, false, true},
     {"keepalive_fix", description_keepalive_fix,
      additional_constraints_keepalive_fix, false, false},
+    {"keepalive_server_fix", description_keepalive_server_fix,
+     additional_constraints_keepalive_server_fix, false, false},
 };
 
 }  // namespace grpc_core
@@ -233,6 +239,10 @@ const char* const description_keepalive_fix =
     "Allows overriding keepalive_permit_without_calls. Refer "
     "https://github.com/grpc/grpc/pull/33428 for more information.";
 const char* const additional_constraints_keepalive_fix = "{}";
+const char* const description_keepalive_server_fix =
+    "Allows overriding keepalive_permit_without_calls for servers. Refer "
+    "https://github.com/grpc/grpc/pull/33917 for more information.";
+const char* const additional_constraints_keepalive_server_fix = "{}";
 #ifdef NDEBUG
 const bool kDefaultForDebugOnly = false;
 #else
@@ -288,6 +298,8 @@ const ExperimentMetadata g_experiment_metadata[] = {
      additional_constraints_unique_metadata_strings, false, true},
     {"keepalive_fix", description_keepalive_fix,
      additional_constraints_keepalive_fix, false, false},
+    {"keepalive_server_fix", description_keepalive_server_fix,
+     additional_constraints_keepalive_server_fix, false, false},
 };
 
 }  // namespace grpc_core
@@ -369,6 +381,10 @@ const char* const description_keepalive_fix =
     "Allows overriding keepalive_permit_without_calls. Refer "
     "https://github.com/grpc/grpc/pull/33428 for more information.";
 const char* const additional_constraints_keepalive_fix = "{}";
+const char* const description_keepalive_server_fix =
+    "Allows overriding keepalive_permit_without_calls for servers. Refer "
+    "https://github.com/grpc/grpc/pull/33917 for more information.";
+const char* const additional_constraints_keepalive_server_fix = "{}";
 #ifdef NDEBUG
 const bool kDefaultForDebugOnly = false;
 #else
@@ -424,6 +440,8 @@ const ExperimentMetadata g_experiment_metadata[] = {
      additional_constraints_unique_metadata_strings, false, true},
     {"keepalive_fix", description_keepalive_fix,
      additional_constraints_keepalive_fix, false, false},
+    {"keepalive_server_fix", description_keepalive_server_fix,
+     additional_constraints_keepalive_server_fix, false, false},
 };
 
 }  // namespace grpc_core

src/core/lib/experiments/experiments.h

@@ -90,6 +90,7 @@ inline bool IsCanaryClientPrivacyEnabled() { return false; }
 inline bool IsServerPrivacyEnabled() { return false; }
 inline bool IsUniqueMetadataStringsEnabled() { return false; }
 inline bool IsKeepaliveFixEnabled() { return false; }
+inline bool IsKeepaliveServerFixEnabled() { return false; }
 
 #elif defined(GPR_WINDOWS)
 inline bool IsTcpFrameSizeTuningEnabled() { return false; }
@@ -123,6 +124,7 @@ inline bool IsCanaryClientPrivacyEnabled() { return false; }
 inline bool IsServerPrivacyEnabled() { return false; }
 inline bool IsUniqueMetadataStringsEnabled() { return false; }
 inline bool IsKeepaliveFixEnabled() { return false; }
+inline bool IsKeepaliveServerFixEnabled() { return false; }
 
 #else
 inline bool IsTcpFrameSizeTuningEnabled() { return false; }
@@ -156,6 +158,7 @@ inline bool IsCanaryClientPrivacyEnabled() { return false; }
 inline bool IsServerPrivacyEnabled() { return false; }
 inline bool IsUniqueMetadataStringsEnabled() { return false; }
 inline bool IsKeepaliveFixEnabled() { return false; }
+inline bool IsKeepaliveServerFixEnabled() { return false; }
 #endif
 
 #else
@@ -209,8 +212,10 @@ inline bool IsServerPrivacyEnabled() { return IsExperimentEnabled(18); }
 inline bool IsUniqueMetadataStringsEnabled() { return IsExperimentEnabled(19); }
 #define GRPC_EXPERIMENT_IS_INCLUDED_KEEPALIVE_FIX
 inline bool IsKeepaliveFixEnabled() { return IsExperimentEnabled(20); }
+#define GRPC_EXPERIMENT_IS_INCLUDED_KEEPALIVE_SERVER_FIX
+inline bool IsKeepaliveServerFixEnabled() { return IsExperimentEnabled(21); }
 
-constexpr const size_t kNumExperiments = 21;
+constexpr const size_t kNumExperiments = 22;
 extern const ExperimentMetadata g_experiment_metadata[kNumExperiments];
 
 #endif

src/core/lib/experiments/experiments.yaml

@@ -166,3 +166,11 @@
   owner: yashkt@google.com
   test_tags: []
   allow_in_fuzzing_config: false
+- name: keepalive_server_fix
+  description:
+    Allows overriding keepalive_permit_without_calls for servers.
+    Refer https://github.com/grpc/grpc/pull/33917 for more information.
+  expiry: 2023/09/07
+  owner: yashkt@google.com
+  test_tags: []
+  allow_in_fuzzing_config: false

src/core/lib/experiments/rollouts.yaml

@@ -90,3 +90,5 @@
   default: false
 - name: keepalive_fix
   default: false
+- name: keepalive_server_fix
+  default: false

test/core/transport/chttp2/ping_configuration_test.cc

@@ -175,6 +175,7 @@ int main(int argc, char** argv) {
   ::testing::InitGoogleTest(&argc, argv);
   grpc::testing::TestEnvironment env(&argc, argv);
   grpc_core::ForceEnableExperiment("keepalive_fix", true);
+  grpc_core::ForceEnableExperiment("keepalive_server_fix", true);
   grpc_init();
   auto ret = RUN_ALL_TESTS();
   grpc_shutdown();