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fix(rc): handle null values in RC APM Tracing payloads #236

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Merged
merged 1 commit into from
Sep 4, 2025
Merged

fix(rc): handle null values in RC APM Tracing payloads #236

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10 changes: 6 additions & 4 deletions src/datadog/config_manager.cpp
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -221,7 +221,7 @@ Expected<ConfigManager::Update> parse_dynamic_config(const nlohmann::json& j) {
ConfigManager::Update config_update;

if (auto sampling_rate_it = j.find("tracing_sampling_rate");
sampling_rate_it != j.cend()) {
sampling_rate_it != j.cend() && !sampling_rate_it->is_null()) {
if (!sampling_rate_it->is_number_float()) {
return make_err_property_msg("tracing_sampling_rate",
sampling_rate_it->type_name());
Expand All @@ -236,7 +236,8 @@ Expected<ConfigManager::Update> parse_dynamic_config(const nlohmann::json& j) {
config_update.trace_sampling_rate = *maybe_rate;
}

if (auto tags_it = j.find("tracing_tags"); tags_it != j.cend()) {
if (auto tags_it = j.find("tracing_tags");
tags_it != j.cend() && !tags_it->is_null()) {
if (!tags_it->is_array()) {
return make_err_property_msg("tracing_tags", tags_it->type_name());
}
Expand All @@ -250,7 +251,7 @@ Expected<ConfigManager::Update> parse_dynamic_config(const nlohmann::json& j) {
}

if (auto tracing_enabled_it = j.find("tracing_enabled");
tracing_enabled_it != j.cend()) {
tracing_enabled_it != j.cend() && !tracing_enabled_it->is_null()) {
if (!tracing_enabled_it->is_boolean()) {
return make_err_property_msg("tracing_enabled",
tracing_enabled_it->type_name());
Expand All @@ -260,7 +261,8 @@ Expected<ConfigManager::Update> parse_dynamic_config(const nlohmann::json& j) {
}

if (auto tracing_sampling_rules_it = j.find("tracing_sampling_rules");
tracing_sampling_rules_it != j.cend()) {
tracing_sampling_rules_it != j.cend() &&
!tracing_sampling_rules_it->is_null()) {
if (!tracing_sampling_rules_it->is_array()) {
return make_err_property_msg("tracing_sampling_rules",
tracing_sampling_rules_it->type_name());
Expand Down
137 changes: 123 additions & 14 deletions test/test_config_manager.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -109,10 +109,31 @@ CONFIG_MANAGER_TEST("remote configuration handling") {
}

SECTION(
"an RC payload without the `tracing_sampling_rate` does not raise an "
"error nor update the sampling rate") {
config_update.content = R"({
"an RC payload without the `tracing_sampling_rate` or with a null "
"value does not raise an error nor update the sampling rate") {
struct TestCase {
size_t line;
std::string_view name;
std::string_view input;
};

const auto test_case = GENERATE(values<TestCase>({
{
__LINE__,
"tracing_sampling_rate is missing",
"",
},
{
__LINE__,
"tracing_sampling_rate is null",
R"("tracing_sampling_rate": null,)",
},
}));

char payload[1024];
std::snprintf(payload, 1024, R"({
"lib_config": {
%s
"library_language": "all",
"library_version": "latest",
"service_name": "testsvc",
Expand All @@ -122,7 +143,13 @@ CONFIG_MANAGER_TEST("remote configuration handling") {
"service": "testsvc",
"env": "test"
}
})";
})",
test_case.input.data());

config_update.content = payload;

CAPTURE(test_case.line);
CAPTURE(test_case.name);

const auto old_trace_sampler_config =
config_manager.trace_sampler()->config_json();
Expand Down Expand Up @@ -232,10 +259,35 @@ CONFIG_MANAGER_TEST("remote configuration handling") {
}

SECTION(
"payload without `tracing_tags` does not raise an error nor update the "
"payload without `tracing_tags` or with a null value does not raise an "
"error nor update the "
"list of tags") {
config_update.content = R"({
struct TestCase {
size_t line;
std::string_view name;
std::string_view input;
};

const auto test_case = GENERATE(values<TestCase>({
{
__LINE__,
"tracing_tags is missing",
"",
},
{
__LINE__,
"tracing_tags is null",
R"("tracing_tags": null,)",
},
}));

CAPTURE(test_case.line);
CAPTURE(test_case.name);

char payload[1024];
std::snprintf(payload, 1024, R"({
"lib_config": {
%s
"library_language": "all",
"library_version": "latest",
"service_name": "testsvc",
Expand All @@ -245,7 +297,10 @@ CONFIG_MANAGER_TEST("remote configuration handling") {
"service": "testsvc",
"env": "test"
}
})";
})",
test_case.input.data());

config_update.content = payload;

const auto old_tags = config_manager.span_defaults()->tags;

Expand Down Expand Up @@ -357,10 +412,34 @@ CONFIG_MANAGER_TEST("remote configuration handling") {
}

SECTION(
"An RC payload without `tracing_enabled` does not raise an error nor "
"update the value") {
config_update.content = R"({
"An RC payload without `tracing_enabled` or with a null value does not "
"raise an error nor update the value") {
struct TestCase {
size_t line;
std::string_view name;
std::string_view input;
};

const auto test_case = GENERATE(values<TestCase>({
{
__LINE__,
"tracing_enabled is absent from the RC payload",
"",
},
{
__LINE__,
"tracing_enabled is null",
R"("tracing_enabled": null,)",
},
}));

CAPTURE(test_case.line);
CAPTURE(test_case.name);

char payload[1024];
std::snprintf(payload, 1024, R"({
"lib_config": {
%s
"library_language": "all",
"library_version": "latest",
"service_name": "testsvc",
Expand All @@ -370,7 +449,10 @@ CONFIG_MANAGER_TEST("remote configuration handling") {
"service": "testsvc",
"env": "test"
}
})";
})",
test_case.input.data());

config_update.content = payload;

const auto old_tracing_status = config_manager.report_traces();

Expand Down Expand Up @@ -526,9 +608,33 @@ CONFIG_MANAGER_TEST("remote configuration handling") {
CHECK(old_sampler_cfg == new_sampler_cfg);
}

SECTION("empty") {
config_update.content = R"({
SECTION("null value or the absence of the field is ignored") {
struct TestCase {
size_t line;
std::string_view name;
std::string_view input;
};

const auto test_case = GENERATE(values<TestCase>({
{
__LINE__,
"tracing_sampling_rules is absent from the RC payload",
"",
},
{
__LINE__,
"tracing_sampling_rules is null",
R"("tracing_sampling_rules": null,)",
},
}));

CAPTURE(test_case.line);
CAPTURE(test_case.name);

char payload[1024];
std::snprintf(payload, 1024, R"({
"lib_config": {
%s
"library_language": "all",
"library_version": "latest",
"service_name": "testsvc",
Expand All @@ -538,7 +644,10 @@ CONFIG_MANAGER_TEST("remote configuration handling") {
"service": "testsvc",
"env": "test"
}
})";
})",
test_case.input.data());

config_update.content = payload;

const auto old_sampler_cfg =
config_manager.trace_sampler()->config_json();
Expand Down