tag_scope.hpp

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#pragma once
 
/// @file userver/tracing/tag_scope.hpp
/// @brief @copybrief tracing::TagScope
 
#include <string>
#include <vector>
 
#include <userver/logging/log_extra.hpp>
#include <userver/tracing/span.hpp>
 
USERVER_NAMESPACE_BEGIN
 
namespace tracing {
 
/// @brief RAII object that calls Span::AddTag / Span::AddTagFrozen function
/// in constructor and reverts these actions in destructor.
///
/// ## Example usage:
/// @snippet tracing/tag_scope_test.cpp  TagScope - sample
class TagScope {
public:
    explicit TagScope(
        std::string key,
        logging::LogExtra::Value value,
        logging::LogExtra::ExtendType extend_type = logging::LogExtra::ExtendType::kNormal
    );
 
    explicit TagScope(
        Span& parent,
        std::string key,
        logging::LogExtra::Value value,
        logging::LogExtra::ExtendType extend_type = logging::LogExtra::ExtendType::kNormal
    );
 
    explicit TagScope(logging::LogExtra&& extra);
 
    explicit TagScope(Span& parent, logging::LogExtra&& extra);
 
    ~TagScope();
 
    TagScope(const TagScope& other) = delete;
    TagScope& operator=(const TagScope& other) = delete;
 
    TagScope(TagScope&& other) = delete;
    TagScope& operator=(TagScope&& other) = delete;
 
private:
    void AddTag(std::string&& key, logging::LogExtra::ProtectedValue&& value);
 
    static constexpr std::size_t kNewKeysVectorSize = 8;
 
    Span& parent_;
    std::size_t new_tags_begin_index_;
    std::size_t new_tags_end_index_;
    std::vector<std::pair<std::size_t, logging::LogExtra::ProtectedValue>> previous_values_;
};
 
}  // namespace tracing
 
USERVER_NAMESPACE_END