runtime: load rtds bool correctly as true/false instead of 1/0 (envoy…

…proxy#36044)

Commit Message: Load RTDS boolean config correctly as true/false instead
of 1/0
Additional Description: Currently, RTDS boolean values are being loaded
as `1` or `0`, which is inconsistent with the expected `true` or `false`
values. This discrepancy needs to be corrected so that boolean values
are consistently loaded and represented as `true` or `false`. For
further details, please refer to the [issue
comment](envoyproxy#35762 (comment))
where this inconsistency is discussed.
Risk Level: Low (to be consistent with initially loaded true/false
value)
Testing: new Unit Test
Docs Changes: n/a
Release Notes: n/a
Platform Specific Features: n/a
[Optional Fixes #Issue] envoyproxy#35762

---------

Signed-off-by: Gordon Wang <gordonwang@lyft.com>

changelogs/current.yaml

@@ -128,6 +128,11 @@ bug_fixes:
     the number of requests per I/O cycle is configured and an HTTP decoder filter that pauses filter chain is present. This behavior
     can be reverted by setting the runtime guard ``envoy.reloadable_features.use_filter_manager_state_for_downstream_end_stream``
     to false.
+- area: runtime
+  change: |
+    Fixed an inconsistency in how boolean values are loaded in RTDS, where they were previously converted to "1"/"0"
+    instead of "true"/"false". The correct string representation ("true"/"false") will now be used. This change can be
+    reverted by setting the runtime guard ``envoy.reloadable_features.boolean_to_string_fix`` to false.
 
 removed_config_or_runtime:
 # *Normally occurs at the end of the* :ref:`deprecation period <deprecated>`

source/common/runtime/runtime_features.cc

@@ -30,6 +30,7 @@
 // ASAP by filing a bug on github. Overriding non-buggy code is strongly discouraged to avoid the
 // problem of the bugs being found after the old code path has been removed.
 RUNTIME_GUARD(envoy_reloadable_features_allow_alt_svc_for_ips);
+RUNTIME_GUARD(envoy_reloadable_features_boolean_to_string_fix);
 RUNTIME_GUARD(envoy_reloadable_features_check_switch_protocol_websocket_handshake);
 RUNTIME_GUARD(envoy_reloadable_features_conn_pool_delete_when_idle);
 RUNTIME_GUARD(envoy_reloadable_features_consistent_header_validation);

source/common/runtime/runtime_impl.cc

@@ -375,7 +375,13 @@ SnapshotImpl::Entry SnapshotImpl::createEntry(const ProtobufWkt::Value& value,
   case ProtobufWkt::Value::kBoolValue:
     entry.bool_value_ = value.bool_value();
     if (entry.raw_string_value_.empty()) {
-      entry.raw_string_value_ = absl::StrCat(value.bool_value());
+      if (Runtime::runtimeFeatureEnabled("envoy.reloadable_features.boolean_to_string_fix")) {
+        // Convert boolean to "true"/"false"
+        entry.raw_string_value_ = value.bool_value() ? "true" : "false";
+      } else {
+        // Use absl::StrCat for backward compatibility, which converts to "1"/"0"
+        entry.raw_string_value_ = absl::StrCat(value.bool_value());
+      }
     }
     break;
   case ProtobufWkt::Value::kStructValue:

test/common/runtime/runtime_impl_test.cc

@@ -32,6 +32,7 @@
 #ifdef ENVOY_ENABLE_QUIC
 #include "quiche/common/platform/api/quiche_flags.h"
 #endif
+ABSL_DECLARE_FLAG(bool, envoy_reloadable_features_boolean_to_string_fix);
 ABSL_DECLARE_FLAG(bool, envoy_reloadable_features_reject_invalid_yaml);
 
 using testing::_;
@@ -1314,6 +1315,40 @@ TEST_F(RtdsLoaderImplTest, BadConfigSource) {
                             "bad config");
 }
 
+TEST_F(RtdsLoaderImplTest, BooleanToStringConversionWhenFlagEnabled) {
+  setup();
+
+  absl::SetFlag(&FLAGS_envoy_reloadable_features_boolean_to_string_fix, true);
+
+  auto runtime = TestUtility::parseYaml<envoy::service::runtime::v3::Runtime>(R"EOF(
+    name: some_resource
+    layer:
+      toggle: true
+  )EOF");
+
+  EXPECT_CALL(rtds_init_callback_, Call());
+  doOnConfigUpdateVerifyNoThrow(runtime);
+
+  EXPECT_EQ("true", loader_->snapshot().get("toggle").value().get());
+}
+
+TEST_F(RtdsLoaderImplTest, BooleanToStringConversionWhenFlagDisabled) {
+  setup();
+
+  absl::SetFlag(&FLAGS_envoy_reloadable_features_boolean_to_string_fix, false);
+
+  auto runtime = TestUtility::parseYaml<envoy::service::runtime::v3::Runtime>(R"EOF(
+    name: some_resource
+    layer:
+      toggle: true
+  )EOF");
+
+  EXPECT_CALL(rtds_init_callback_, Call());
+  doOnConfigUpdateVerifyNoThrow(runtime);
+
+  EXPECT_EQ("1", loader_->snapshot().get("toggle").value().get()); // Assuming previous behavior
+}
+
 } // namespace
 } // namespace Runtime
 } // namespace Envoy