opentelemetry-cpp/api/include/opentelemetry/plugin/factory.h

66 lines
2.1 KiB
C++

// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0
#pragma once
#include <memory>
#include <string>
#include "opentelemetry/plugin/detail/utility.h" // IWYU pragma: export
#include "opentelemetry/plugin/tracer.h"
#include "opentelemetry/version.h"
OPENTELEMETRY_BEGIN_NAMESPACE
namespace plugin
{
/**
* Factory creates OpenTelemetry objects from configuration strings.
*/
class Factory final
{
public:
class FactoryImpl
{
public:
virtual ~FactoryImpl() {}
virtual nostd::unique_ptr<TracerHandle> MakeTracerHandle(
nostd::string_view tracer_config,
nostd::unique_ptr<char[]> &error_message) const noexcept = 0;
};
Factory(std::shared_ptr<DynamicLibraryHandle> library_handle,
std::unique_ptr<FactoryImpl> &&factory_impl) noexcept
: library_handle_{std::move(library_handle)}, factory_impl_{std::move(factory_impl)}
{}
/**
* Construct a tracer from a configuration string.
* @param tracer_config a representation of the tracer's config as a string.
* @param error_message on failure this will contain an error message.
* @return a Tracer on success or nullptr on failure.
*/
std::shared_ptr<trace::Tracer> MakeTracer(nostd::string_view tracer_config,
std::string &error_message) const noexcept
{
nostd::unique_ptr<char[]> plugin_error_message;
auto tracer_handle = factory_impl_->MakeTracerHandle(tracer_config, plugin_error_message);
if (tracer_handle == nullptr)
{
detail::CopyErrorMessage(plugin_error_message.get(), error_message);
return nullptr;
}
return std::shared_ptr<trace::Tracer>{new (std::nothrow)
Tracer{library_handle_, std::move(tracer_handle)}};
}
private:
// Note: The order is important here.
//
// It's undefined behavior to close the library while a loaded FactoryImpl is still active.
std::shared_ptr<DynamicLibraryHandle> library_handle_;
std::unique_ptr<FactoryImpl> factory_impl_;
};
} // namespace plugin
OPENTELEMETRY_END_NAMESPACE