Linker error when building otlp_grpc_exporter_test

[svrnm]

Describe your environment

• Alpine Linux v3.16 on Aarch64

Steps to reproduce

• Commands I am running:

      sudo apk add cmake grpc-dev re2-dev protobuf-dev c-ares-dev curl-dev nlohmann-json thrift-dev boost-dev
      sudo apk add gtest-dev benchmark-dev
      git clone https://github.com/open-telemetry/opentelemetry-cpp.git
      cd opentelemetry-cpp
      cmake -B build \
              -DCMAKE_INSTALL_PREFIX=/usr \
              -DWITH_PROMETHEUS=OFF \
              -DBUILD_SHARED_LIBS=ON \
              -DCMAKE_POSITION_INDEPENDENT_CODE=ON \
              -DCMAKE_BUILD_TYPE=Release \
              -DBUILD_TESTING=ON \
              -DWITH_EXAMPLES=OFF \
              -DWITH_OTLP=ON \
              -DWITH_OTLP_HTTP=ON \
              -DWITH_JAEGER=ON \
              -DWITH_ZIPKIN=ON
      cmake --build build
  

What is the expected behavior?
No error

What is the actual behavior?
Linker error:

[ 83%] Linking CXX executable otlp_grpc_exporter_test
/usr/lib/gcc/aarch64-alpine-linux-musl/11.2.1/../../../../aarch64-alpine-linux-musl/bin/ld: CMakeFiles/otlp_grpc_exporter_test.dir/test/otlp_grpc_exporter_test.cc.o: undefined reference to symbol '_ZN4grpc6Status2OKE'
/usr/lib/gcc/aarch64-alpine-linux-musl/11.2.1/../../../../aarch64-alpine-linux-musl/bin/ld: /usr/lib/libgrpc++.so.1.46: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
make[2]: *** [exporters/otlp/CMakeFiles/otlp_grpc_exporter_test.dir/build.make:109: exporters/otlp/otlp_grpc_exporter_test] Error 1
make[1]: *** [CMakeFiles/Makefile2:4940: exporters/otlp/CMakeFiles/otlp_grpc_exporter_test.dir/all] Error 2
make: *** [Makefile:146: all] Error 2

Additional context
I can work around this issue by setting export LDFLAGS="$LDFLAGS -Wl,--copy-dt-needed-entries" but I don't think that's a permanent solution

[ThomsonTan]

@svrnm could you please try if the link error can be fixed by adding #include <grpcpp/grpcpp.h> to the beginning of below test file and right after the line #ifndef HAVE_CPP_STDLIB?

https://github.com/open-telemetry/opentelemetry-cpp/blob/main/exporters/otlp/test/otlp_grpc_exporter_test.cc

[svrnm]

@ThomsonTan it works with WITH_STL=ON set for cmake, I assume that's the effect you're looking for? (I can also try to apply the #ifndef as well)

[svrnm]

Ignore my last comment, it was stupid;-)

So, I tried adding grpcpp via the include but still got the error, but the following worked:

diff --git a/exporters/otlp/CMakeLists.txt b/exporters/otlp/CMakeLists.txt
index 49db605..fa15689 100644
--- a/exporters/otlp/CMakeLists.txt
+++ b/exporters/otlp/CMakeLists.txt
@@ -226,7 +226,7 @@ if(BUILD_TESTING)
   if(WITH_OTLP_GRPC)
     add_executable(otlp_grpc_exporter_test test/otlp_grpc_exporter_test.cc)
     target_link_libraries(
-      otlp_grpc_exporter_test ${GTEST_BOTH_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT}
+      otlp_grpc_exporter_test gRPC::grpc++ ${GTEST_BOTH_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT}
       ${GMOCK_LIB} opentelemetry_exporter_otlp_grpc)
     gtest_add_tests(
       TARGET otlp_grpc_exporter_test

I can raise a PR to get this fixed, just wanted to check first if this is the right approach?

[owent]

I'm not familar with alpine with musl toolchains, but according to #1891 and #1603 , linking gRPC::grpc++ into more than one executables and dynamic libraries may be dangerous, depends how we build gRPC and otep-cpp.
I may be wrong but maybe -Wl,--copy-dt-needed-entries is a better solution here.

[marcalff]

@svrnm

The title says otlp_http_exporter_test ... this is about otlp_grpc_exporter_test, right ?

[svrnm]

@svrnm

The title says otlp_http_exporter_test ... this is about otlp_grpc_exporter_test, right ?

fixed

I'm not familar with alpine with musl toolchains, but according to #1891 and #1603 , linking gRPC::grpc++ into more than one executables and dynamic libraries may be dangerous, depends how we build gRPC and otep-cpp.
I may be wrong but maybe -Wl,--copy-dt-needed-entries is a better solution here.

So the fix I applied for the package eventually is using WITH_STL=ON. If this issue is isolated to musl I guess we can close it as wont fix.

[ThomsonTan]

@owent do you think the below dependence on grpc++ can be marked as public? Which may fix the issue as well?

opentelemetry-cpp/exporters/otlp/CMakeLists.txt

Lines 38 to 39 in 2544803

	target_link_libraries(opentelemetry_exporter_otlp_grpc_client
	PRIVATE gRPC::grpc++)

[owent]

@owent do you think the below dependence on grpc++ can be marked as public? Which may fix the issue as well?

opentelemetry-cpp/exporters/otlp/CMakeLists.txt

Lines 38 to 39 in 2544803

	target_link_libraries(opentelemetry_exporter_otlp_grpc_client
	PRIVATE gRPC::grpc++)

No, in my understanding, grpc++ can not be marked as public, the reason of #1603 is linking grpc into more than one dynamic libraries and executable.

[github-actions]

This issue was marked as stale due to lack of activity.