9.2/includes/opentelemetry/trace/tracer.h

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// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0
 
#pragma once
 
#include <chrono>
 
#include "opentelemetry/context/context.h"
#include "opentelemetry/nostd/shared_ptr.h"
#include "opentelemetry/nostd/string_view.h"
#include "opentelemetry/trace/default_span.h"
#include "opentelemetry/trace/scope.h"
#include "opentelemetry/trace/span.h"
#include "opentelemetry/trace/span_context_kv_iterable_view.h"
#include "opentelemetry/trace/span_startoptions.h"
#include "opentelemetry/version.h"
 
OPENTELEMETRY_BEGIN_NAMESPACE
namespace trace
{
class Tracer
{
public:
  virtual ~Tracer() = default;
  virtual nostd::shared_ptr<Span> StartSpan(nostd::string_view name,
                                            const common::KeyValueIterable &attributes,
                                            const SpanContextKeyValueIterable &links,
                                            const StartSpanOptions &options = {}) noexcept = 0;
 
  nostd::shared_ptr<Span> StartSpan(nostd::string_view name,
                                    const StartSpanOptions &options = {}) noexcept
  {
    return this->StartSpan(name, {}, {}, options);
  }
 
  template <class T,
            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
  nostd::shared_ptr<Span> StartSpan(nostd::string_view name,
                                    const T &attributes,
                                    const StartSpanOptions &options = {}) noexcept
  {
    return this->StartSpan(name, attributes, {}, options);
  }
 
  nostd::shared_ptr<Span> StartSpan(nostd::string_view name,
                                    const common::KeyValueIterable &attributes,
                                    const StartSpanOptions &options = {}) noexcept
  {
    return this->StartSpan(name, attributes, NullSpanContext(), options);
  }
 
  template <class T,
            class U,
            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr,
            nostd::enable_if_t<detail::is_span_context_kv_iterable<U>::value>   * = nullptr>
  nostd::shared_ptr<Span> StartSpan(nostd::string_view name,
                                    const T &attributes,
                                    const U &links,
                                    const StartSpanOptions &options = {}) noexcept
  {
    return this->StartSpan(name, common::KeyValueIterableView<T>(attributes),
                           SpanContextKeyValueIterableView<U>(links), options);
  }
 
  nostd::shared_ptr<Span> StartSpan(
      nostd::string_view name,
      std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>> attributes,
      const StartSpanOptions &options = {}) noexcept
  {
 
    return this->StartSpan(name, attributes, {}, options);
  }
 
  template <class T,
            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
  nostd::shared_ptr<Span> StartSpan(
      nostd::string_view name,
      const T &attributes,
      std::initializer_list<
          std::pair<SpanContext,
                    std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>>>
          links,
      const StartSpanOptions &options = {}) noexcept
  {
    return this->StartSpan(
        name, attributes,
        nostd::span<const std::pair<SpanContext, std::initializer_list<std::pair<
                                                     nostd::string_view, common::AttributeValue>>>>{
            links.begin(), links.end()},
        options);
  }
 
  template <class T,
            nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
  nostd::shared_ptr<Span> StartSpan(
      nostd::string_view name,
      std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>> attributes,
      const T &links,
      const StartSpanOptions &options = {}) noexcept
  {
    return this->StartSpan(name,
                           nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>{
                               attributes.begin(), attributes.end()},
                           links, options);
  }
 
  nostd::shared_ptr<Span> StartSpan(
      nostd::string_view name,
      std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>> attributes,
      std::initializer_list<
          std::pair<SpanContext,
                    std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>>>
          links,
      const StartSpanOptions &options = {}) noexcept
  {
    return this->StartSpan(
        name,
        nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>{attributes.begin(),
                                                                                 attributes.end()},
        nostd::span<const std::pair<SpanContext, std::initializer_list<std::pair<
                                                     nostd::string_view, common::AttributeValue>>>>{
            links.begin(), links.end()},
        options);
  }
 
  static Scope WithActiveSpan(nostd::shared_ptr<Span> &span) noexcept { return Scope{span}; }
 
  static nostd::shared_ptr<Span> GetCurrentSpan() noexcept
  {
    context::ContextValue active_span = context::RuntimeContext::GetValue(kSpanKey);
    if (nostd::holds_alternative<nostd::shared_ptr<Span>>(active_span))
    {
      return nostd::get<nostd::shared_ptr<Span>>(active_span);
    }
    else
    {
      return nostd::shared_ptr<Span>(new DefaultSpan(SpanContext::GetInvalid()));
    }
  }
 
#if OPENTELEMETRY_ABI_VERSION_NO >= 2
 
  bool Enabled() const noexcept { return OPENTELEMETRY_ATOMIC_READ_8(&this->enabled_) != 0; }
#endif
 
#if OPENTELEMETRY_ABI_VERSION_NO == 1
 
  /*
   * The following is removed from the API in ABI version 2.
   * It belongs to the SDK.
   */
 
  template <class Rep, class Period>
  void ForceFlush(std::chrono::duration<Rep, Period> timeout) noexcept
  {
    this->ForceFlushWithMicroseconds(static_cast<uint64_t>(
        std::chrono::duration_cast<std::chrono::microseconds>(timeout).count()));
  }
 
  virtual void ForceFlushWithMicroseconds(uint64_t timeout) noexcept = 0;
 
  template <class Rep, class Period>
  void Close(std::chrono::duration<Rep, Period> timeout) noexcept
  {
    this->CloseWithMicroseconds(static_cast<uint64_t>(
        std::chrono::duration_cast<std::chrono::microseconds>(timeout).count()));
  }
 
  virtual void CloseWithMicroseconds(uint64_t timeout) noexcept = 0;
 
#endif /* OPENTELEMETRY_ABI_VERSION_NO */
 
protected:
#if OPENTELEMETRY_ABI_VERSION_NO >= 2
 
  void UpdateEnabled(const bool enabled) noexcept
  {
    OPENTELEMETRY_ATOMIC_WRITE_8(&this->enabled_, enabled);
  }
#endif
 
private:
#if OPENTELEMETRY_ABI_VERSION_NO >= 2
  // Variable to support implementation of Enabled method introduced in ABI V2.
  // Mutable allows enabled_ to be used as 'bool *' (instead of 'const bool *'), with the
  // OPENTELEMETRY_ATOMIC_READ_8 macro's internal casts when used from a const function.
  // std::atomic can not be used here because it is not ABI compatible for OpenTelemetry C++ API.
  mutable bool enabled_ = true;
#endif
};
}  // namespace trace
OPENTELEMETRY_END_NAMESPACE