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// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0
#pragma once
#include <cstdint>
#include "opentelemetry/common/attribute_value.h"
#include "opentelemetry/common/key_value_iterable_view.h"
#include "opentelemetry/nostd/span.h"
#include "opentelemetry/nostd/string_view.h"
#include "opentelemetry/nostd/type_traits.h"
#include "opentelemetry/trace/span_context.h"
#include "opentelemetry/trace/span_context_kv_iterable.h"
#include "opentelemetry/trace/span_context_kv_iterable_view.h"
#include "opentelemetry/trace/span_metadata.h"
#include "opentelemetry/version.h"
OPENTELEMETRY_BEGIN_NAMESPACE
namespace trace
{
class Tracer;
/**
* A Span represents a single operation within a Trace.
*
* Span attributes can be provided:
* - at span creation time, using Tracer::StartSpan(),
* - during the span lifetime, using Span::SetAttribute()
*
* Please note that head samplers,
* in the SDK (@ref opentelemetry::sdk::trace::Sampler),
* can only make sampling decisions based on data known
* at span creation time.
*
* When attributes are known early, adding attributes
* with @ref opentelemetry::trace::Tracer::StartSpan() is preferable.
*
* Attributes added or changed with Span::SetAttribute()
* can not change a sampler decision.
*
* Likewise, links can be provided:
* - at span creation time, using Tracer::StartSpan(),
* - during the span lifetime, using Span::AddLink() or Span::AddLinks().
*
* When links are known early, adding links
* with @ref opentelemetry::trace::Tracer::StartSpan() is preferable.
*
* Links added with Span::AddLink() or Span::AddLinks()
* can not change a sampler decision.
*/
class Span
{
public:
// Note that Spans should be created using the Tracer class. Please refer to
// tracer.h for documentation.
Span() = default;
// The Span destructor End()s the Span, if it hasn't been ended already.
virtual ~Span() = default;
// Not copiable or movable.
Span(const Span &) = delete;
Span(Span &&) = delete;
Span &operator=(const Span &) = delete;
Span &operator=(Span &&) = delete;
/**
* Sets an attribute on the Span (ABI).
*
* If the Span previously contained a mapping for the key,
* the old value is replaced.
*
* See comments about sampling in @ref opentelemetry::trace::Span
*/
virtual void SetAttribute(nostd::string_view key,
const common::AttributeValue &value) noexcept = 0;
// Adds an event to the Span.
virtual void AddEvent(nostd::string_view name) noexcept = 0;
// Adds an event to the Span, with a custom timestamp.
virtual void AddEvent(nostd::string_view name, common::SystemTimestamp timestamp) noexcept = 0;
// Adds an event to the Span, with a custom timestamp, and attributes.
virtual void AddEvent(nostd::string_view name,
common::SystemTimestamp timestamp,
const common::KeyValueIterable &attributes) noexcept = 0;
virtual void AddEvent(nostd::string_view name,
const common::KeyValueIterable &attributes) noexcept
{
this->AddEvent(name, std::chrono::system_clock::now(), attributes);
}
template <class T,
nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
void AddEvent(nostd::string_view name,
common::SystemTimestamp timestamp,
const T &attributes) noexcept
{
this->AddEvent(name, timestamp, common::KeyValueIterableView<T>{attributes});
}
template <class T,
nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
void AddEvent(nostd::string_view name, const T &attributes) noexcept
{
this->AddEvent(name, common::KeyValueIterableView<T>{attributes});
}
void AddEvent(nostd::string_view name,
common::SystemTimestamp timestamp,
std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
attributes) noexcept
{
this->AddEvent(name, timestamp,
nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>{
attributes.begin(), attributes.end()});
}
void AddEvent(nostd::string_view name,
std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>
attributes) noexcept
{
this->AddEvent(name, std::chrono::system_clock::now(),
nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>{
attributes.begin(), attributes.end()});
}
#if OPENTELEMETRY_ABI_VERSION_NO >= 2
/**
* Add link (ABI).
*
* See comments about sampling in @ref opentelemetry::trace::Span
*
* @since ABI_VERSION 2
*/
virtual void AddLink(const SpanContext &target,
const common::KeyValueIterable &attrs) noexcept = 0;
/**
* Add links (ABI).
*
* See comments about sampling in @ref opentelemetry::trace::Span
*
* @since ABI_VERSION 2
*/
virtual void AddLinks(const SpanContextKeyValueIterable &links) noexcept = 0;
/**
* Add link (API helper).
*
* See comments about sampling in @ref opentelemetry::trace::Span
*
* @since ABI_VERSION 2
*/
template <class U,
nostd::enable_if_t<common::detail::is_key_value_iterable<U>::value> * = nullptr>
void AddLink(const SpanContext &target, const U &attrs)
{
common::KeyValueIterableView<U> view(attrs);
this->AddLink(target, view);
}
/**
* Add link (API helper).
*
* See comments about sampling in @ref opentelemetry::trace::Span
*
* @since ABI_VERSION 2
*/
void AddLink(const SpanContext &target,
std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>> attrs)
{
/* Build a container from std::initializer_list. */
nostd::span<const std::pair<nostd::string_view, common::AttributeValue>> container{
attrs.begin(), attrs.end()};
/* Build a view on the container. */
common::KeyValueIterableView<
nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>>
view(container);
return this->AddLink(target, view);
}
/**
* Add links (API helper).
*
* See comments about sampling in @ref opentelemetry::trace::Span
*
* @since ABI_VERSION 2
*/
template <class U, nostd::enable_if_t<detail::is_span_context_kv_iterable<U>::value> * = nullptr>
void AddLinks(const U &links)
{
SpanContextKeyValueIterableView<U> view(links);
this->AddLinks(view);
}
/**
* Add links (API helper).
*
* See comments about sampling in @ref opentelemetry::trace::Span
*
* @since ABI_VERSION 2
*/
void AddLinks(
std::initializer_list<
std::pair<SpanContext,
std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>>>
links)
{
/* Build a container from std::initializer_list. */
nostd::span<const std::pair<
SpanContext, std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>>>
container{links.begin(), links.end()};
/* Build a view on the container. */
SpanContextKeyValueIterableView<nostd::span<const std::pair<
SpanContext, std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>>>>
view(container);
return this->AddLinks(view);
}
#endif /* OPENTELEMETRY_ABI_VERSION_NO */
// Sets the status of the span. The default status is Unset. Only the value of
// the last call will be
// recorded, and implementations are free to ignore previous calls.
virtual void SetStatus(StatusCode code, nostd::string_view description = "") noexcept = 0;
// Updates the name of the Span. If used, this will override the name provided
// during creation.
virtual void UpdateName(nostd::string_view name) noexcept = 0;
/**
* Mark the end of the Span.
* Only the timing of the first End call for a given Span will be recorded,
* and implementations are free to ignore all further calls.
* @param options can be used to manually define span properties like the end
* timestamp
*/
virtual void End(const trace::EndSpanOptions &options = {}) noexcept = 0;
virtual trace::SpanContext GetContext() const noexcept = 0;
// Returns true if this Span is recording tracing events (e.g. SetAttribute,
// AddEvent).
virtual bool IsRecording() const noexcept = 0;
};
} // namespace trace
OPENTELEMETRY_END_NAMESPACE