Allow custom GIT_TAG for OpenTelemetry.

Author: kinyoklion

README.md

@@ -66,6 +66,9 @@ Various CMake options are available to customize the client/server SDK builds.
 | `LD_DYNAMIC_LINK_OPENSSL`     | Whether OpenSSL is dynamically linked or not.                                                                                                                                                                                                                            | Off  (static link)                                     | N/A                                       |
 | `LD_BUILD_REDIS_SUPPORT`      | Whether the server-side Redis Source is built or not.                                                                                                                                                                                                                    | Off                                                    | N/A                                       |
 | `LD_CURL_NETWORKING`          | Enable CURL-based networking for all HTTP requests (SSE streams and event delivery). When OFF, Boost.Beast/Foxy is used instead. CURL must be available as a dependency when this option is ON.                                                                          | Off                                                    | N/A                                       |
+| `LD_BUILD_OTEL_SUPPORT`       | Whether the server-side OpenTelemetry integration package is built or not.                                                                                                                                                                                                | Off                                                    | N/A                                       |
+| `LD_BUILD_OTEL_FETCH_DEPS`    | When building OpenTelemetry support, automatically fetch and configure OpenTelemetry dependencies via CMake FetchContent. This is useful for local development and CI. When OFF, you must provide OpenTelemetry yourself via `find_package`.                              | Off                                                    | `LD_BUILD_OTEL_SUPPORT`                   |
+| `LD_OTEL_CPP_VERSION`         | Specifies the OpenTelemetry C++ SDK version (git tag or commit hash) to fetch when `LD_BUILD_OTEL_FETCH_DEPS` is enabled. Can be set to any valid git reference from the [opentelemetry-cpp repository](https://github.com/open-telemetry/opentelemetry-cpp).            | `ea1f0d61ce5baa5584b097266bf133d1f31e3607` (v1.23.0)  | `LD_BUILD_OTEL_FETCH_DEPS`                |
 
 > [!WARNING]   
 > When building shared libraries C++ symbols are not exported, only the C API will be exported. This is because C++ does

libs/server-sdk-otel/CMakeLists.txt

@@ -24,6 +24,10 @@ endif ()
 # Option for local development and CI builds
 option(LD_BUILD_OTEL_FETCH_DEPS "Fetch OpenTelemetry dependencies for local/CI builds" OFF)
 
+# Allow users to specify which version of OpenTelemetry to fetch
+# Default to v1.23.0 (commit ea1f0d61ce5baa5584b097266bf133d1f31e3607)
+set(LD_OTEL_CPP_VERSION "ea1f0d61ce5baa5584b097266bf133d1f31e3607" CACHE STRING "OpenTelemetry C++ SDK version (git tag or commit hash)")
+
 if (LD_BUILD_OTEL_FETCH_DEPS)
     # For local development and CI: fetch OpenTelemetry with sensible defaults
     message("LaunchDarkly: fetching OpenTelemetry dependencies for local/CI build")
@@ -44,7 +48,7 @@ if (LD_BUILD_OTEL_FETCH_DEPS)
     FetchContent_Declare(
         opentelemetry-cpp
         GIT_REPOSITORY https://github.com/open-telemetry/opentelemetry-cpp.git
-        GIT_TAG ea1f0d61ce5baa5584b097266bf133d1f31e3607  # v1.23.0
+        GIT_TAG ${LD_OTEL_CPP_VERSION}
     )
     FetchContent_MakeAvailable(opentelemetry-cpp)
 else()