[EXPORTER] Allow to share gRPC clients between OTLP exporters (#3041)

Author: owent

CHANGELOG.md

@@ -27,6 +27,9 @@ Increment the:
 * [SEMANTIC CONVENTIONS] Migration to weaver
   [#3105](https://github.com/open-telemetry/opentelemetry-cpp/pull/3105)
 
+* [EXPORTER] Allow to share gRPC clients between OTLP exporters.
+  [#3041](https://github.com/open-telemetry/opentelemetry-cpp/pull/3041)
+
 Important changes:
 
 * [API] Jaeger Propagator should not be deprecated

CMakeLists.txt

@@ -389,14 +389,8 @@ if(WITH_OTLP_GRPC
    OR WITH_OTLP_HTTP
    OR WITH_OTLP_FILE)
   find_package(Protobuf)
-  if(Protobuf_VERSION AND Protobuf_VERSION VERSION_GREATER_EQUAL "3.22.0")
-    if(NOT WITH_ABSEIL)
-      message(
-        FATAL_ERROR
-          "Protobuf 3.22 or upper require abseil-cpp(Recommended version: 20230125 or upper)"
-      )
-    endif()
-  endif()
+  # Protobuf 3.22 or upper require abseil-cpp, we can find it in
+  # opentelemetry-cpp-config.cmake
 
   if(WITH_OTLP_GRPC)
     find_package(gRPC)

api/include/opentelemetry/nostd/internal/absl/README.md

@@ -1,4 +1,4 @@
 # Notes on Abseil Variant implementation
 
-This is a snapshot of Abseil Variant `absl::variant` from Abseil
-`v2020-03-03#8`.
+This is a snapshot of Abseil Variant
+`absl::OTABSL_OPTION_NAMESPACE_NAME::variant` from Abseil `v2020-03-03#8`.

api/include/opentelemetry/nostd/internal/absl/base/config.h

@@ -84,7 +84,7 @@
 // namespace absl {
 // OTABSL_NAMESPACE_BEGIN
 //
-// void Foo();  // absl::Foo().
+// void Foo();  // absl::OTABSL_OPTION_NAMESPACE_NAME::Foo().
 //
 // OTABSL_NAMESPACE_END
 // }  // namespace absl
@@ -94,40 +94,32 @@
 // not support forward declarations of its own types, nor does it support
 // user-provided specialization of Abseil templates.  Code that violates these
 // rules may be broken without warning.)
-#if !defined(OTABSL_OPTION_USE_INLINE_NAMESPACE) || \
-    !defined(OTABSL_OPTION_INLINE_NAMESPACE_NAME)
+#if !defined(OTABSL_OPTION_NAMESPACE_NAME)
 #error options.h is misconfigured.
 #endif
 
-// Check that OTABSL_OPTION_INLINE_NAMESPACE_NAME is neither "head" nor ""
-#if defined(__cplusplus) && OTABSL_OPTION_USE_INLINE_NAMESPACE == 1
+// Check that OTABSL_OPTION_NAMESPACE_NAME is neither "head" nor ""
+#if defined(__cplusplus)
 
 #define OTABSL_INTERNAL_INLINE_NAMESPACE_STR \
-  OTABSL_INTERNAL_TOKEN_STR(OTABSL_OPTION_INLINE_NAMESPACE_NAME)
+  OTABSL_INTERNAL_TOKEN_STR(OTABSL_OPTION_NAMESPACE_NAME)
 
 static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != '\0',
-              "options.h misconfigured: OTABSL_OPTION_INLINE_NAMESPACE_NAME must "
+              "options.h misconfigured: OTABSL_OPTION_NAMESPACE_NAME must "
               "not be empty.");
 static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
                   OTABSL_INTERNAL_INLINE_NAMESPACE_STR[1] != 'e' ||
                   OTABSL_INTERNAL_INLINE_NAMESPACE_STR[2] != 'a' ||
                   OTABSL_INTERNAL_INLINE_NAMESPACE_STR[3] != 'd' ||
                   OTABSL_INTERNAL_INLINE_NAMESPACE_STR[4] != '\0',
-              "options.h misconfigured: OTABSL_OPTION_INLINE_NAMESPACE_NAME must "
+              "options.h misconfigured: OTABSL_OPTION_NAMESPACE_NAME must "
               "be changed to a new, unique identifier name.");
 
 #endif
 
-#if OTABSL_OPTION_USE_INLINE_NAMESPACE == 0
-#define OTABSL_NAMESPACE_BEGIN
-#define OTABSL_NAMESPACE_END
-#elif OTABSL_OPTION_USE_INLINE_NAMESPACE == 1
-#define OTABSL_NAMESPACE_BEGIN \
-  inline namespace OTABSL_OPTION_INLINE_NAMESPACE_NAME {
+
+#define OTABSL_NAMESPACE_BEGIN namespace OTABSL_OPTION_NAMESPACE_NAME {
 #define OTABSL_NAMESPACE_END }
-#else
-#error options.h is misconfigured.
-#endif
 
 // -----------------------------------------------------------------------------
 // Compiler Feature Checks
@@ -217,7 +209,7 @@ static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 
 // OTABSL_HAVE_SOURCE_LOCATION_CURRENT
 //
-// Indicates whether `absl::SourceLocation::current()` will return useful
+// Indicates whether `absl::OTABSL_OPTION_NAMESPACE_NAME::SourceLocation::current()` will return useful
 // information in some contexts.
 #ifndef OTABSL_HAVE_SOURCE_LOCATION_CURRENT
 #if OTABSL_INTERNAL_HAS_KEYWORD(__builtin_LINE) && \
@@ -570,7 +562,7 @@ static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 
 // OTABSL_USES_STD_ANY
 //
-// Indicates whether absl::any is an alias for std::any.
+// Indicates whether absl::OTABSL_OPTION_NAMESPACE_NAME::any is an alias for std::any.
 #if !defined(OTABSL_OPTION_USE_STD_ANY)
 #error options.h is misconfigured.
 #elif OTABSL_OPTION_USE_STD_ANY == 0 || \
@@ -585,7 +577,7 @@ static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 
 // OTABSL_USES_STD_OPTIONAL
 //
-// Indicates whether absl::optional is an alias for std::optional.
+// Indicates whether absl::OTABSL_OPTION_NAMESPACE_NAME::optional is an alias for std::optional.
 #if !defined(OTABSL_OPTION_USE_STD_OPTIONAL)
 #error options.h is misconfigured.
 #elif OTABSL_OPTION_USE_STD_OPTIONAL == 0 || \
@@ -600,7 +592,7 @@ static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 
 // OTABSL_USES_STD_VARIANT
 //
-// Indicates whether absl::variant is an alias for std::variant.
+// Indicates whether absl::OTABSL_OPTION_NAMESPACE_NAME::variant is an alias for std::variant.
 #if !defined(OTABSL_OPTION_USE_STD_VARIANT)
 #error options.h is misconfigured.
 #elif OTABSL_OPTION_USE_STD_VARIANT == 0 || \
@@ -615,7 +607,7 @@ static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 
 // OTABSL_USES_STD_STRING_VIEW
 //
-// Indicates whether absl::string_view is an alias for std::string_view.
+// Indicates whether absl::OTABSL_OPTION_NAMESPACE_NAME::string_view is an alias for std::string_view.
 #if !defined(OTABSL_OPTION_USE_STD_STRING_VIEW)
 #error options.h is misconfigured.
 #elif OTABSL_OPTION_USE_STD_STRING_VIEW == 0 || \
@@ -650,15 +642,10 @@ static_assert(OTABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 // the proper count to skip past the CCTZ fork namespace names.  (This number
 // is one larger when there is an inline namespace name to skip.)
 #if defined(_MSC_VER)
-#if OTABSL_OPTION_USE_INLINE_NAMESPACE == 0
-#define OTABSL_INTERNAL_MANGLED_NS "absl"
-#define OTABSL_INTERNAL_MANGLED_BACKREFERENCE "5"
-#else
 #define OTABSL_INTERNAL_MANGLED_NS \
-  OTABSL_INTERNAL_TOKEN_STR(OTABSL_OPTION_INLINE_NAMESPACE_NAME) "@absl"
+  OTABSL_INTERNAL_TOKEN_STR(OTABSL_OPTION_NAMESPACE_NAME) "@absl"
 #define OTABSL_INTERNAL_MANGLED_BACKREFERENCE "6"
 #endif
-#endif
 
 #undef OTABSL_INTERNAL_HAS_KEYWORD
 

api/include/opentelemetry/nostd/internal/absl/base/internal/inline_variable.h

@@ -68,15 +68,15 @@
 //   types, etc..
 #if defined(__clang__)
 #define OTABSL_INTERNAL_EXTERN_DECL(type, name) \
-  extern const ::absl::OTABSL_OPTION_INLINE_NAMESPACE_NAME::internal::identity_t<type> name;
+  extern const ::absl::OTABSL_OPTION_NAMESPACE_NAME::internal::identity_t<type> name;
 #else  // Otherwise, just define the macro to do nothing.
 #define OTABSL_INTERNAL_EXTERN_DECL(type, name)
 #endif  // defined(__clang__)
 
 // See above comment at top of file for details.
 #define OTABSL_INTERNAL_INLINE_CONSTEXPR(type, name, init) \
   OTABSL_INTERNAL_EXTERN_DECL(type, name)                  \
-  inline constexpr ::absl::OTABSL_OPTION_INLINE_NAMESPACE_NAME::internal::identity_t<type> name = init
+  inline constexpr ::absl::OTABSL_OPTION_NAMESPACE_NAME::internal::identity_t<type> name = init
 
 #else
 
@@ -89,14 +89,14 @@
 #define OTABSL_INTERNAL_INLINE_CONSTEXPR(var_type, name, init)                  \
   template <class /*AbslInternalDummy*/ = void>                               \
   struct AbslInternalInlineVariableHolder##name {                             \
-    static constexpr ::absl::OTABSL_OPTION_INLINE_NAMESPACE_NAME::internal::identity_t<var_type> kInstance = init; \
+    static constexpr ::absl::OTABSL_OPTION_NAMESPACE_NAME::internal::identity_t<var_type> kInstance = init; \
   };                                                                          \
                                                                               \
   template <class AbslInternalDummy>                                          \
-  constexpr ::absl::OTABSL_OPTION_INLINE_NAMESPACE_NAME::internal::identity_t<var_type>                            \
+  constexpr ::absl::OTABSL_OPTION_NAMESPACE_NAME::internal::identity_t<var_type>                            \
       AbslInternalInlineVariableHolder##name<AbslInternalDummy>::kInstance;   \
                                                                               \
-  static constexpr const ::absl::OTABSL_OPTION_INLINE_NAMESPACE_NAME::internal::identity_t<var_type>&              \
+  static constexpr const ::absl::OTABSL_OPTION_NAMESPACE_NAME::internal::identity_t<var_type>&              \
       name = /* NOLINT */                                                     \
       AbslInternalInlineVariableHolder##name<>::kInstance;                    \
   static_assert(sizeof(void (*)(decltype(name))) != 0,                        \

api/include/opentelemetry/nostd/internal/absl/base/internal/invoke.h

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 //
-// absl::base_internal::Invoke(f, args...) is an implementation of
+// absl::OTABSL_OPTION_NAMESPACE_NAME::base_internal::Invoke(f, args...) is an implementation of
 // INVOKE(f, args...) from section [func.require] of the C++ standard.
 //
 // [func.require]
@@ -73,7 +73,7 @@ struct MemFunAndRef : StrippedAccept<MemFunAndRef> {
   template <typename MemFunType, typename C, typename Obj, typename... Args>
   struct AcceptImpl<MemFunType C::*, Obj, Args...>
       : std::integral_constant<bool, std::is_base_of<C, Obj>::value &&
-                                         absl::is_function<MemFunType>::value> {
+                                         absl::OTABSL_OPTION_NAMESPACE_NAME::is_function<MemFunType>::value> {
   };
 
   template <typename MemFun, typename Obj, typename... Args>
@@ -94,7 +94,7 @@ struct MemFunAndPtr : StrippedAccept<MemFunAndPtr> {
   template <typename MemFunType, typename C, typename Ptr, typename... Args>
   struct AcceptImpl<MemFunType C::*, Ptr, Args...>
       : std::integral_constant<bool, !std::is_base_of<C, Ptr>::value &&
-                                         absl::is_function<MemFunType>::value> {
+                                         absl::OTABSL_OPTION_NAMESPACE_NAME::is_function<MemFunType>::value> {
   };
 
   template <typename MemFun, typename Ptr, typename... Args>
@@ -116,7 +116,7 @@ struct DataMemAndRef : StrippedAccept<DataMemAndRef> {
   template <typename R, typename C, typename Obj>
   struct AcceptImpl<R C::*, Obj>
       : std::integral_constant<bool, std::is_base_of<C, Obj>::value &&
-                                         !absl::is_function<R>::value> {};
+                                         !absl::OTABSL_OPTION_NAMESPACE_NAME::is_function<R>::value> {};
 
   template <typename DataMem, typename Ref>
   static decltype(std::declval<Ref>().*std::declval<DataMem>()) Invoke(
@@ -134,7 +134,7 @@ struct DataMemAndPtr : StrippedAccept<DataMemAndPtr> {
   template <typename R, typename C, typename Ptr>
   struct AcceptImpl<R C::*, Ptr>
       : std::integral_constant<bool, !std::is_base_of<C, Ptr>::value &&
-                                         !absl::is_function<R>::value> {};
+                                         !absl::OTABSL_OPTION_NAMESPACE_NAME::is_function<R>::value> {};
 
   template <typename DataMem, typename Ptr>
   static decltype((*std::declval<Ptr>()).*std::declval<DataMem>()) Invoke(

api/include/opentelemetry/nostd/internal/absl/base/macros.h

@@ -41,7 +41,7 @@
 // can be used in defining new arrays. If you use this macro on a pointer by
 // mistake, you will get a compile-time error.
 #define OTABSL_ARRAYSIZE(array) \
-  (sizeof(::absl::macros_internal::ArraySizeHelper(array)))
+  (sizeof(::absl::OTABSL_OPTION_NAMESPACE_NAME::macros_internal::ArraySizeHelper(array)))
 
 namespace absl {
 OTABSL_NAMESPACE_BEGIN
@@ -60,7 +60,7 @@ OTABSL_NAMESPACE_END
 // static storage duration, and that the constructor should do nothing to its
 // state. Use of this macro indicates to the reader that it is legal to
 // declare a static instance of the class, provided the constructor is given
-// the absl::base_internal::kLinkerInitialized argument.
+// the absl::OTABSL_OPTION_NAMESPACE_NAME::base_internal::kLinkerInitialized argument.
 //
 // Normally, it is unsafe to declare a static variable that has a constructor or
 // a destructor because invocation order is undefined. However, if the type can
@@ -70,10 +70,10 @@ OTABSL_NAMESPACE_END
 //
 // Example:
 //       // Declaration
-//       explicit MyClass(absl::base_internal:LinkerInitialized x) {}
+//       explicit MyClass(absl::OTABSL_OPTION_NAMESPACE_NAME::base_internal:LinkerInitialized x) {}
 //
 //       // Invocation
-//       static MyClass my_global(absl::base_internal::kLinkerInitialized);
+//       static MyClass my_global(absl::OTABSL_OPTION_NAMESPACE_NAME::base_internal::kLinkerInitialized);
 namespace absl {
 OTABSL_NAMESPACE_BEGIN
 namespace base_internal {

api/include/opentelemetry/nostd/internal/absl/base/options.h

@@ -79,7 +79,7 @@
 //
 // OTABSL_OPTION_USE_STD_ANY
 //
-// This option controls whether absl::any is implemented as an alias to
+// This option controls whether absl::OTABSL_OPTION_NAMESPACE_NAME::any is implemented as an alias to
 // std::any, or as an independent implementation.
 //
 // A value of 0 means to use Abseil's implementation.  This requires only C++11
@@ -93,19 +93,19 @@
 // useful when you are building your entire program, including all of its
 // dependencies, from source.  It should not be used otherwise -- for example,
 // if you are distributing Abseil in a binary package manager -- since in
-// mode 2, absl::any will name a different type, with a different mangled name
+// mode 2, absl::OTABSL_OPTION_NAMESPACE_NAME::any will name a different type, with a different mangled name
 // and binary layout, depending on the compiler flags passed by the end user.
 // For more info, see https://abseil.io/about/design/dropin-types.
 //
 // User code should not inspect this macro.  To check in the preprocessor if
-// absl::any is a typedef of std::any, use the feature macro OTABSL_USES_STD_ANY.
+// absl::OTABSL_OPTION_NAMESPACE_NAME::any is a typedef of std::any, use the feature macro OTABSL_USES_STD_ANY.
 
 #define OTABSL_OPTION_USE_STD_ANY 0
 
 
 // OTABSL_OPTION_USE_STD_OPTIONAL
 //
-// This option controls whether absl::optional is implemented as an alias to
+// This option controls whether absl::OTABSL_OPTION_NAMESPACE_NAME::optional is implemented as an alias to
 // std::optional, or as an independent implementation.
 //
 // A value of 0 means to use Abseil's implementation.  This requires only C++11
@@ -118,21 +118,21 @@
 // and use an alias only if a working std::optional is available.  This option
 // is useful when you are building your program from source.  It should not be
 // used otherwise -- for example, if you are distributing Abseil in a binary
-// package manager -- since in mode 2, absl::optional will name a different
+// package manager -- since in mode 2, absl::OTABSL_OPTION_NAMESPACE_NAME::optional will name a different
 // type, with a different mangled name and binary layout, depending on the
 // compiler flags passed by the end user.  For more info, see
 // https://abseil.io/about/design/dropin-types.
 
 // User code should not inspect this macro.  To check in the preprocessor if
-// absl::optional is a typedef of std::optional, use the feature macro
+// absl::OTABSL_OPTION_NAMESPACE_NAME::optional is a typedef of std::optional, use the feature macro
 // OTABSL_USES_STD_OPTIONAL.
 
 #define OTABSL_OPTION_USE_STD_OPTIONAL 0
 
 
 // OTABSL_OPTION_USE_STD_STRING_VIEW
 //
-// This option controls whether absl::string_view is implemented as an alias to
+// This option controls whether absl::OTABSL_OPTION_NAMESPACE_NAME::string_view is implemented as an alias to
 // std::string_view, or as an independent implementation.
 //
 // A value of 0 means to use Abseil's implementation.  This requires only C++11
@@ -145,20 +145,20 @@
 // and use an alias only if a working std::string_view is available.  This
 // option is useful when you are building your program from source.  It should
 // not be used otherwise -- for example, if you are distributing Abseil in a
-// binary package manager -- since in mode 2, absl::string_view will name a
+// binary package manager -- since in mode 2, absl::OTABSL_OPTION_NAMESPACE_NAME::string_view will name a
 // different type, with a different mangled name and binary layout, depending on
 // the compiler flags passed by the end user.  For more info, see
 // https://abseil.io/about/design/dropin-types.
 //
 // User code should not inspect this macro.  To check in the preprocessor if
-// absl::string_view is a typedef of std::string_view, use the feature macro
+// absl::OTABSL_OPTION_NAMESPACE_NAME::string_view is a typedef of std::string_view, use the feature macro
 // OTABSL_USES_STD_STRING_VIEW.
 
 #define OTABSL_OPTION_USE_STD_STRING_VIEW 0
 
 // OTABSL_OPTION_USE_STD_VARIANT
 //
-// This option controls whether absl::variant is implemented as an alias to
+// This option controls whether absl::OTABSL_OPTION_NAMESPACE_NAME::variant is implemented as an alias to
 // std::variant, or as an independent implementation.
 //
 // A value of 0 means to use Abseil's implementation.  This requires only C++11
@@ -171,41 +171,23 @@
 // and use an alias only if a working std::variant is available.  This option
 // is useful when you are building your program from source.  It should not be
 // used otherwise -- for example, if you are distributing Abseil in a binary
-// package manager -- since in mode 2, absl::variant will name a different
+// package manager -- since in mode 2, absl::OTABSL_OPTION_NAMESPACE_NAME::variant will name a different
 // type, with a different mangled name and binary layout, depending on the
 // compiler flags passed by the end user.  For more info, see
 // https://abseil.io/about/design/dropin-types.
 //
 // User code should not inspect this macro.  To check in the preprocessor if
-// absl::variant is a typedef of std::variant, use the feature macro
+// absl::OTABSL_OPTION_NAMESPACE_NAME::variant is a typedef of std::variant, use the feature macro
 // OTABSL_USES_STD_VARIANT.
 
 #define OTABSL_OPTION_USE_STD_VARIANT 0
 
 
-// OTABSL_OPTION_USE_INLINE_NAMESPACE
-// OTABSL_OPTION_INLINE_NAMESPACE_NAME
+// OTABSL_OPTION_NAMESPACE_NAME
 //
-// These options controls whether all entities in the absl namespace are
-// contained within an inner inline namespace.  This does not affect the
-// user-visible API of Abseil, but it changes the mangled names of all symbols.
-//
-// This can be useful as a version tag if you are distributing Abseil in
-// precompiled form.  This will prevent a binary library build of Abseil with
-// one inline namespace being used with headers configured with a different
-// inline namespace name.  Binary packagers are reminded that Abseil does not
-// guarantee any ABI stability in Abseil, so any update of Abseil or
-// configuration change in such a binary package should be combined with a
-// new, unique value for the inline namespace name.
-//
-// A value of 0 means not to use inline namespaces.
-//
-// A value of 1 means to use an inline namespace with the given name inside
-// namespace absl.  If this is set, OTABSL_OPTION_INLINE_NAMESPACE_NAME must also
-// be changed to a new, unique identifier name.  In particular "head" is not
-// allowed.
+// All codes in otabsl are under OTABSL_OPTION_NAMESPACE_NAME, we do not use inline namespace to avoid
+// conlict with external Abseil.
 
-#define OTABSL_OPTION_USE_INLINE_NAMESPACE 1
-#define OTABSL_OPTION_INLINE_NAMESPACE_NAME otel_v1
+#define OTABSL_OPTION_NAMESPACE_NAME otel_v1
 
 #endif  // OTABSL_BASE_OPTIONS_H_