Merge branch 'main' into expo-histo-aggregation-4

Author: ThomsonTan

.github/workflows/cmake_install.yml

@@ -8,10 +8,13 @@ on:
     branches: [ main ]
 
 jobs:
-  windows_2022_vcpkg:
-    name: Windows 2022 vcpkg cxx17 (static libs - dll)
+  windows_2022_vcpkg_submodule:
+    name: Windows 2022 vcpkg submodule versions cxx17 (static libs - dll)
     runs-on: windows-2022
     env:
+      # Set to the latest version of cmake 3.x
+      CMAKE_VERSION: '3.31.6'
+      # cxx17 is the default for windows-2022
       CXX_STANDARD: '17'
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
@@ -26,10 +29,13 @@ jobs:
       - name: Run DLL Tests
         run: ./ci/do_ci.ps1 cmake.dll.install.test
 
-  windows_2019_vcpkg:
-    name: Windows 2019 vcpkg cxx14 (static libs)
+  windows_2019_vcpkg_submodule_min_cmake:
+    name: Windows 2019 vcpkg submodule versions minimum cmake cxx14 (static libs)
     runs-on: windows-2019
     env:
+      # cmake 3.15 is the minimum for windows builds (See https://github.com/open-telemetry/opentelemetry-cpp/pull/3349#discussion_r2030319430)
+      CMAKE_VERSION: '3.15.0'
+      # cxx14 is the default for windows-2019
       CXX_STANDARD: '14'
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
@@ -47,6 +53,9 @@ jobs:
     runs-on: ubuntu-24.04
     env:
       INSTALL_TEST_DIR: '/home/runner/install_test'
+      # CMake 3.28 is apt package version for Ubuntu 24.04
+      CMAKE_VERSION: '3.28.3'
+      # cxx17 is the default for Ubuntu 24.04
       CXX_STANDARD: '17'
       BUILD_TYPE: 'Debug'
     steps:
@@ -71,12 +80,22 @@ jobs:
         BUILD_SHARED_LIBS: 'ON'
       run: ./ci/do_ci.sh cmake.install.test
 
-  ubuntu_2404_script_build_grpc_1_71_0:
-    name: Ubuntu 24.04 script grpc 1.71.0 cxx17 (static libs)
+  ubuntu_2404_latest:
+    name: Ubuntu 24.04 latest versions cxx20 (static libs)
     runs-on: ubuntu-24.04
     env:
       INSTALL_TEST_DIR: '/home/runner/install_test'
+      # Set to the latest version of cmake 3.x
+      CMAKE_VERSION: '3.31.6'
+      # Set to the latest cxx standard supported by opentelemetry-cpp
       CXX_STANDARD: '20'
+      # Versions below set to the latest version available
+      # The abseil and protobuf versions are taken from
+      # the grpc submodules at the GRPC_VERSION tag
+      GOOGLETEST_VERSION: '1.16.0'
+      ABSEIL_CPP_VERSION: '20240722.1'
+      PROTOBUF_VERSION: '29.0'
+      GRPC_VERSION: 'v1.71.0'
       BUILD_TYPE: 'Debug'
     steps:
     - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
@@ -88,10 +107,6 @@ jobs:
         sudo -E ./ci/setup_cmake.sh
         sudo -E ./ci/setup_googletest.sh
     - name: Build abseil, protobuf, and grpc with ci scripts
-      env:
-        ABSEIL_CPP_VERSION: '20240722.1'
-        PROTOBUF_VERSION: '29.0'
-        GRPC_VERSION: 'v1.71.0'
       run: |
         sudo -E ./ci/install_abseil.sh
         sudo -E ./ci/install_protobuf.sh
@@ -101,12 +116,20 @@ jobs:
         BUILD_SHARED_LIBS: 'OFF'
       run: ./ci/do_ci.sh cmake.install.test
 
-  ubuntu_2204_script_build_grpc_1_55_0:
-    name: Ubuntu 22.04 script grpc 1.55.0 cxx17 (static libs - shared libs)
+  ubuntu_2204_stable:
+    name: Ubuntu 22.04 stable versions cxx17 (static libs - shared libs)
     runs-on: ubuntu-22.04
     env:
       INSTALL_TEST_DIR: '/home/runner/install_test'
+      # CMake 3.22 is the apt package version for Ubuntu 22.04
+      CMAKE_VERSION: '3.22.0'
       CXX_STANDARD: '17'
+      # These are stable versions tested in the main ci workflow
+      # and defaults in the devcontainer
+      GOOGLETEST_VERSION: '1.14.0'
+      ABSEIL_CPP_VERSION: '20230125.3'
+      PROTOBUF_VERSION: '23.3'
+      GRPC_VERSION: 'v1.55.0'
       BUILD_TYPE: 'Debug'
     steps:
     - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
@@ -118,10 +141,6 @@ jobs:
         sudo -E ./ci/setup_cmake.sh
         sudo -E ./ci/setup_googletest.sh
     - name: Build abseil, protobuf, and grpc with ci scripts
-      env:
-        ABSEIL_CPP_VERSION: '20230125.3'
-        PROTOBUF_VERSION: '23.3'
-        GRPC_VERSION: 'v1.55.0'
       run: |
         sudo -E ./ci/install_abseil.sh
         sudo -E ./ci/install_protobuf.sh
@@ -135,12 +154,21 @@ jobs:
         BUILD_SHARED_LIBS: 'ON'
       run: ./ci/do_ci.sh cmake.install.test
 
-  ubuntu_2204_script_build_grpc_1_49_2:
-    name: Ubuntu 22.04 script grpc 1.49.2 cxx14 (static libs - shared libs)
+  ubuntu_2204_minimum:
+    name: Ubuntu 22.04 minimum versions cxx14 (static libs - shared libs)
     runs-on: ubuntu-22.04
     env:
       INSTALL_TEST_DIR: '/home/runner/install_test'
+      # Set to the current minimum version of cmake
+      CMAKE_VERSION: '3.14.0'
+      # cxx14 is the default for Ubuntu 22.04
       CXX_STANDARD: '14'
+      # This is the apt package version of googletest for Ubuntu 22.04
+      GOOGLETEST_VERSION: '1.11.0'
+      # These are minimum versions tested in the main ci workflow
+      ABSEIL_CPP_VERSION: '20220623.2'
+      PROTOBUF_VERSION: '21.12'
+      GRPC_VERSION: 'v1.49.2'
       BUILD_TYPE: 'Debug'
     steps:
     - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
@@ -152,10 +180,6 @@ jobs:
         sudo -E ./ci/setup_cmake.sh
         sudo -E ./ci/setup_googletest.sh
     - name: Build abseil, protobuf, and grpc with ci scripts
-      env:
-        ABSEIL_CPP_VERSION: '20220623.2'
-        PROTOBUF_VERSION: '21.12'
-        GRPC_VERSION: 'v1.49.2'
       run: |
         sudo -E ./ci/install_abseil.sh
         sudo -E ./ci/install_protobuf.sh
@@ -170,10 +194,12 @@ jobs:
       run: ./ci/do_ci.sh cmake.install.test
 
   ubuntu_2404_conan_stable:
-    name: Ubuntu 24.04 conan stable cxx17 (static libs - shared libs - opentracing shim)
+    name: Ubuntu 24.04 conan stable versions cxx17 (static libs - shared libs - opentracing shim)
     runs-on: ubuntu-24.04
     env:
       INSTALL_TEST_DIR: '/home/runner/install_test'
+       # CMake 3.28 is apt package version for Ubuntu 24.04
+      CMAKE_VERSION: '3.28.3'
       CXX_STANDARD: '17'
       CMAKE_TOOLCHAIN_FILE: /home/runner/conan/build/Debug/generators/conan_toolchain.cmake
       BUILD_TYPE: 'Debug'
@@ -189,7 +215,7 @@ jobs:
       - name: Install or build all dependencies with Conan
         run: |
           sudo -E ./ci/setup_cmake.sh
-          conan install install/conan/conanfile_stable.txt --build=missing -of /home/runner/conan -s build_type=Debug
+          conan install install/conan/conanfile_stable.txt --build=missing -of /home/runner/conan -s build_type=${BUILD_TYPE} -s compiler.cppstd=${CXX_STANDARD}
       - name: Run Tests (static libs)
         env:
           BUILD_SHARED_LIBS: 'OFF'
@@ -206,10 +232,12 @@ jobs:
         run: ./ci/do_ci.sh cmake.opentracing_shim.install.test
 
   ubuntu_2404_conan_latest:
-    name: Ubuntu 24.04 conan latest cxx17 (static libs)
+    name: Ubuntu 24.04 conan latest versions cxx17 (static libs)
     runs-on: ubuntu-24.04
     env:
       INSTALL_TEST_DIR: '/home/runner/install_test'
+      # Set to the latest version of cmake 3.x
+      CMAKE_VERSION: '3.31.6'
       CXX_STANDARD: '17'
       CMAKE_TOOLCHAIN_FILE: /home/runner/conan/build/Debug/generators/conan_toolchain.cmake
       BUILD_TYPE: 'Debug'
@@ -225,7 +253,7 @@ jobs:
       - name: Install or build all dependencies with Conan
         run: |
           sudo -E ./ci/setup_cmake.sh
-          conan install install/conan/conanfile_latest.txt --build=missing -of /home/runner/conan -s build_type=Debug
+          conan install install/conan/conanfile_latest.txt --build=missing -of /home/runner/conan -s build_type=${BUILD_TYPE} -s compiler.cppstd=${CXX_STANDARD}
       - name: Run Tests (static libs)
         env:
           BUILD_SHARED_LIBS: 'OFF'
@@ -236,10 +264,11 @@ jobs:
           ./ci/verify_packages.sh
 
   macos_14_conan_stable:
-    name: macOS 14 conan stable cxx17 (static libs)
+    name: macOS 14 conan stable versions cxx17 (static libs)
     runs-on: macos-14
     env:
       INSTALL_TEST_DIR: '/Users/runner/install_test'
+      CMAKE_VERSION: '3.28.3'
       CXX_STANDARD: '17'
       CMAKE_TOOLCHAIN_FILE: '/Users/runner/conan/build/Debug/generators/conan_toolchain.cmake'
       BUILD_TYPE: 'Debug'
@@ -250,19 +279,22 @@ jobs:
     - name: Install Conan and tools
       run: |
         brew install conan autoconf automake libtool coreutils
-        sudo -E ./ci/setup_cmake_macos.sh
+        ./ci/setup_cmake_macos.sh
         conan profile detect --force
     - name: Install or build all dependencies with Conan
-      run: conan install install/conan/conanfile_stable.txt --build=missing -of /Users/runner/conan -s build_type=Debug
+      run: conan install install/conan/conanfile_stable.txt --build=missing -of /Users/runner/conan -s build_type=${BUILD_TYPE} -s compiler.cppstd=${CXX_STANDARD}
     - name: Run Tests (static libs)
       env:
         BUILD_SHARED_LIBS: 'OFF'
       run: ./ci/do_ci.sh cmake.install.test
 
   macos_14_brew_packages:
-    name: macOS 14 brew packages cxx17 (static libs)
+    name: macOS 14 brew latest versions cxx17 (static libs)
     runs-on: macos-14
     env:
+      INSTALL_TEST_DIR: '/Users/runner/install_test'
+      # Set to the latest version of cmake 3.x
+      CMAKE_VERSION: '3.31.6'
       CXX_STANDARD: '17'
       BUILD_TYPE: 'Debug'
     steps:
@@ -271,7 +303,7 @@ jobs:
         submodules: 'recursive'
     - name: Install Dependencies with Homebrew
       run: |
-        sudo -E ./ci/setup_cmake_macos.sh
+        ./ci/setup_cmake_macos.sh
         brew install coreutils
         brew install googletest
         brew install google-benchmark

CHANGELOG.md

@@ -29,6 +29,9 @@ Increment the:
 * [API] Remove `WITH_ABSEIL` and `HAVE_ABSEIL`
   [#3318](https://github.com/open-telemetry/opentelemetry-cpp/pull/3318)
 
+* [CMAKE] Bump cmake minimum required version to 3.14
+  [#3349](https://github.com/open-telemetry/opentelemetry-cpp/pull/3349)
+
 ## [1.20 2025-04-01]
 
 * [BUILD] Update opentelemetry-proto version

CMakeLists.txt

@@ -1,7 +1,7 @@
 # Copyright The OpenTelemetry Authors
 # SPDX-License-Identifier: Apache-2.0
 
-cmake_minimum_required(VERSION 3.10)
+cmake_minimum_required(VERSION 3.14)
 
 # See https://cmake.org/cmake/help/latest/policy/CMP0074.html required by
 # certain version of zlib which CURL depends on.
@@ -36,8 +36,9 @@ project(opentelemetry-cpp)
 # Mark variables as used so cmake doesn't complain about them
 mark_as_advanced(CMAKE_TOOLCHAIN_FILE)
 
-# Prefer cmake CONFIG to auto resolve dependencies. This is important to
-# properly find protobuf versions 3.22.0 and above
+# Note: CMAKE_FIND_PACKAGE_PREFER_CONFIG requires cmake 3.15. Prefer cmake
+# CONFIG search mode to find dependencies. This is important to properly find
+# protobuf versions 3.22.0 and above due to the abseil-cpp dependency.
 set(CMAKE_FIND_PACKAGE_PREFER_CONFIG TRUE)
 
 # Don't use customized cmake modules if vcpkg is used to resolve dependence.
@@ -420,15 +421,32 @@ if(WITH_OTLP_GRPC
    OR WITH_OTLP_HTTP
    OR WITH_OTLP_FILE)
 
-  find_package(Protobuf)
-  # Protobuf 3.22 or upper require abseil-cpp, we can find it in
-  # opentelemetry-cpp-config.cmake
+  # Including the CMakeFindDependencyMacro resolves an error from
+  # gRPCConfig.cmake on some grpc versions. See
+  # https://github.com/grpc/grpc/pull/33361 for more details.
+  include(CMakeFindDependencyMacro)
+
+  # Protobuf 3.22+ depends on abseil-cpp and must be found using the cmake
+  # find_package CONFIG search mode. The following attempts to find Protobuf
+  # using the CONFIG mode first, and if not found, falls back to the MODULE
+  # mode. See https://gitlab.kitware.com/cmake/cmake/-/issues/24321 for more
+  # details.
+  find_package(Protobuf CONFIG)
+  if(NOT Protobuf_FOUND)
+    find_package(Protobuf MODULE)
+    if(Protobuf_FOUND AND Protobuf_VERSION VERSION_GREATER_EQUAL "3.22.0")
+      message(
+        WARNING
+          "Found Protobuf version ${Protobuf_VERSION} using MODULE mode. "
+          "Linking errors may occur. Protobuf 3.22+ depends on abseil-cpp "
+          "and should be found using the CONFIG mode.")
+    endif()
+  endif()
 
   if(WITH_OTLP_GRPC)
     find_package(gRPC CONFIG)
   endif()
-  if((NOT Protobuf_FOUND AND NOT PROTOBUF_FOUND) OR (WITH_OTLP_GRPC
-                                                     AND NOT gRPC_FOUND))
+  if((NOT Protobuf_FOUND) OR (WITH_OTLP_GRPC AND NOT gRPC_FOUND))
     if(WIN32 AND (NOT DEFINED CMAKE_TOOLCHAIN_FILE))
       install_windows_deps()
     endif()
@@ -440,8 +458,8 @@ if(WITH_OTLP_GRPC
       include(${CMAKE_TOOLCHAIN_FILE})
     endif()
 
-    if(NOT Protobuf_FOUND AND NOT PROTOBUF_FOUND)
-      find_package(Protobuf REQUIRED)
+    if(NOT Protobuf_FOUND)
+      find_package(Protobuf CONFIG REQUIRED)
     endif()
     if(NOT gRPC_FOUND AND WITH_OTLP_GRPC)
       find_package(gRPC CONFIG)
@@ -502,6 +520,11 @@ endif()
 if((NOT WITH_API_ONLY) AND WITH_HTTP_CLIENT_CURL)
   # No specific version required.
   find_package(CURL REQUIRED)
+  # Set the CURL_VERSION from the legacy CURL_VERSION_STRING Required for CMake
+  # versions below 4.0
+  if(NOT DEFINED CURL_VERSION AND DEFINED CURL_VERSION_STRING)
+    set(CURL_VERSION ${CURL_VERSION_STRING})
+  endif()
 endif()
 
 #
@@ -513,6 +536,11 @@ if((NOT WITH_API_ONLY)
    AND WITH_OTLP_HTTP_COMPRESSION)
   # No specific version required.
   find_package(ZLIB REQUIRED)
+  # Set the ZLIB_VERSION from the legacy ZLIB_VERSION_STRING Required for CMake
+  # versions below 3.26
+  if(NOT DEFINED ZLIB_VERSION AND DEFINED ZLIB_VERSION_STRING)
+    set(ZLIB_VERSION ${ZLIB_VERSION_STRING})
+  endif()
 endif()
 
 #

INSTALL.md

@@ -23,7 +23,9 @@ You can link OpenTelemetry C++ SDK with libraries provided in
   repository. To install Git, consult the [Set up
   Git](https://help.github.com/articles/set-up-git/) guide on GitHub.
 - [CMake](https://cmake.org/) for building opentelemetry-cpp API, SDK with their
-  unittests. We use CMake version 3.15.2 in our build system. To install CMake,
+  unittests. The minimum CMake version is 3.14.
+  CMake 3.15+ is recommended on Windows due to known CI test failures with 3.14.
+  To install CMake,
   consult the [Installing CMake](https://cmake.org/install/) guide.
 - [GoogleTest](https://github.com/google/googletest) framework to build and run
   the unittests. Refer to