Unit test failing in CI: OtlpHttpExporterTestPeer.ExportJsonIntegrationTest

[lalitb]

One of the failure instances:
https://github.com/open-telemetry/opentelemetry-cpp/runs/4083453037?check_suite_focus=true

[ RUN      ] OtlpHttpExporterTestPeer.ExportJsonIntegrationTest
exporters/otlp/test/otlp_http_exporter_test.cc:240: Failure
Value of: waitForRequests(2, old_count + 1)
  Actual: false
Expected: true
[  FAILED  ] OtlpHttpExporterTestPeer.ExportJsonIntegrationTest (4446 ms)

[ThomsonTan]

Wondering why this was not caught by our PR build.

[lalitb]

Wondering why this was not caught by our PR build.

I don't think it is failing consistently, so not got caught in our PR build

[esigo]

This was happening here as well #1044 (comment).

[lalitb]

Haven't seen this happening this week, probably a transient issue with the CI pipeline. Will watch for some more time before closing.

[owent]

I find it takes a lot time to finish tests when run under valgrind . It almost take 6 seconds to finish this test even in a successful case.
Maybe just increasing timeout could help?

[esigo]

It happened again. I'll try to raise a PR with mock in the next coming days.

[owent]

It happened again. I'll try to raise a PR with mock in the next coming days.

Thanks. Maybe it's also better to use multi_handle instead of start a new thread to start a asynchronous HTTP request when using libcurl.Should I start another issue?

[lalitb]

Thanks. Maybe it's also better to use multi_handle instead of start a new thread to start a asynchronous HTTP request when using libcurl.Should I start another issue?

Thank @owent. Which thread invocation are we talking about here? The only place a potential thread may get created internally for libcurl is here -

opentelemetry-cpp/ext/include/opentelemetry/ext/http/client/curl/http_operation_curl.h

Line 298 in 16a9c53

result_ = std::async(std::launch::async, [this, callback] {

Do we want to remove it, and instead use multi_handle?

[owent]

Reference in

Thanks. Maybe it's also better to use multi_handle instead of start a new thread to start a asynchronous HTTP request when using libcurl.Should I start another issue?

Thank @owent. Which thread invocation are we talking about here? The only place a potential thread may get created internally for libcurl is here -

opentelemetry-cpp/ext/include/opentelemetry/ext/http/client/curl/http_operation_curl.h

Line 298 in 16a9c53

result_ = std::async(std::launch::async, [this, callback] {

Do we want to remove it, and instead use multi_handle?

Yes, I can create another issue and try to use multi_handle after #1209 is merged.It can reduce the cost when there are a lot sessions.