Skip to content

[SDK] Ensure TraceId is portable on big-endian architectures #3543

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 3 commits into from
Jul 16, 2025
Merged

[SDK] Ensure TraceId is portable on big-endian architectures #3543

Show file tree
Hide file tree
Changes from 2 commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
9377a5d
[SDK] Ensure TraceId is portable on big-endian architectures
strophy Jul 16, 2025
4ba7cad
Merge branch 'main' into s390x-endianness-traceid-fix
marcalff Jul 16, 2025
6c02f81
Update trace_id_ratio.cc
marcalff Jul 16, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 7 additions & 2 deletions sdk/src/trace/samplers/trace_id_ratio.cc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -56,8 +56,13 @@ uint64_t CalculateThresholdFromBuffer(const trace_api::TraceId &trace_id) noexce
// We only use the first 8 bytes of TraceId.
static_assert(trace_api::TraceId::kSize >= 8, "TraceID must be at least 8 bytes long.");

uint64_t res = 0;
std::memcpy(&res, &trace_id, 8);
// Always interpret as big-endian
const uint8_t *data = trace_id.Id().data();
uint64_t res = 0;
for (int i = 0; i < 8; ++i)
{
res = (res << 8) | data[i];
}

double ratio = static_cast<double>(res) / static_cast<double>(UINT64_MAX);

Expand Down
2 changes: 1 addition & 1 deletion sdk/test/trace/trace_id_ratio_sampler_test.cc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -99,7 +99,7 @@ TEST(TraceIdRatioBasedSampler, ShouldSampleWithoutContext)
ASSERT_EQ(Decision::RECORD_AND_SAMPLE, sampling_result.decision);
ASSERT_EQ(nullptr, sampling_result.attributes);

constexpr uint8_t buf[] = {0, 0, 0, 0, 0, 0, 0, 0x80, 0, 0, 0, 0, 0, 0, 0, 0};
constexpr uint8_t buf[] = {0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
trace_api::TraceId valid_trace_id(buf);

sampling_result = s1.ShouldSample(trace_api::SpanContext::GetInvalid(), valid_trace_id, "",
Expand Down
Loading