- The API must have zero dependencies and be header-only.
Pros: allows you to drop it into a source tree (i.e. vendor it) without changing the build or adding a dependency.
-
The SDK should have minimal dependencies.
-
Exporters can bring in transport dependencies, e.g. Stackdriver exporter depends on gRPC.
-
Support both static linking and dynamic loading.
Dynamic loading is required because some vendors want to drop in their own implementation of the SDK. It also allows low-dependency builds.
This also requires a stable C++ ABI. There is quite a bit of interest in this.
This means STL types can't be used in the interface.
- OpenTelemetry should not require a dedicated thread for background work and exporters.