Building otlp exporter from the release tarball (#1056)

CMakeLists.txt

@@ -20,6 +20,16 @@ if(NOT DEFINED CMAKE_TOOLCHAIN_FILE)
   list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake/modules/")
 endif()
 
+if(EXISTS "${CMAKE_SOURCE_DIR}/third_party_release")
+  file(STRINGS "${CMAKE_SOURCE_DIR}/third_party_release" third_party_tags)
+  foreach(third_party ${third_party_tags})
+    string(REGEX REPLACE "^[ ]+" "" third_party ${third_party})
+    string(REGEX MATCH "^[^=]+" third_party_name ${third_party})
+    string(REPLACE "${third_party_name}=" "" third_party_tag ${third_party})
+    set(${third_party_name} "${third_party_tag}")
+  endforeach()
+endif()
+
 if(DEFINED ENV{ARCH})
   # Architecture may be specified via ARCH environment variable
   set(ARCH $ENV{ARCH})

cmake/opentelemetry-proto.cmake

@@ -1,6 +1,36 @@
-include(${PROJECT_SOURCE_DIR}/cmake/proto-options-patch.cmake)
+if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/third_party/opentelemetry-proto/.git)
+    set(PROTO_PATH "${CMAKE_CURRENT_SOURCE_DIR}/third_party/opentelemetry-proto")
+    set(needs_proto_download FALSE)
+else()
+    if("${opentelemetry-proto}" STREQUAL "")
+        set(opentelemetry-proto "main")
+    endif()
+    include(ExternalProject)
+    ExternalProject_Add(opentelemetry-proto
+    GIT_REPOSITORY https://github.com/open-telemetry/opentelemetry-proto.git
+    GIT_TAG
+        "${opentelemetry-proto}"
+    UPDATE_COMMAND ""
+    BUILD_COMMAND ""
+    INSTALL_COMMAND ""
+    CONFIGURE_COMMAND ""
+    TEST_AFTER_INSTALL
+        0
+    DOWNLOAD_NO_PROGRESS
+        1
+    LOG_CONFIGURE
+        1
+    LOG_BUILD
+        1
+    LOG_INSTALL
+        1
+    )
+    ExternalProject_Get_Property(opentelemetry-proto INSTALL_DIR)
+    set(PROTO_PATH "${INSTALL_DIR}/src/opentelemetry-proto")
+    set(needs_proto_download TRUE)
+endif()
 
-set(PROTO_PATH "${CMAKE_CURRENT_SOURCE_DIR}/third_party/opentelemetry-proto")
+include(${PROJECT_SOURCE_DIR}/cmake/proto-options-patch.cmake)
 
 set(COMMON_PROTO "${PROTO_PATH}/opentelemetry/proto/common/v1/common.proto")
 set(RESOURCE_PROTO
@@ -138,6 +168,9 @@ add_library(
   ${METRICS_SERVICE_PB_CPP_FILE}
   ${METRICS_SERVICE_GRPC_PB_CPP_FILE})
 
+if(needs_proto_download)
+    add_dependencies(opentelemetry_proto opentelemetry-proto)
+endif()
 set_target_properties(opentelemetry_proto PROPERTIES EXPORT_NAME proto)
 patch_protobuf_targets(opentelemetry_proto)