source.hpp

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#pragma once
 
/// @file userver/alerts/source.hpp
/// @brief @copybrief alerts::Source
 
#include <chrono>
#include <string_view>
 
#include <userver/utils/statistics/metric_tag.hpp>
#include <userver/utils/statistics/metrics_storage.hpp>
 
USERVER_NAMESPACE_BEGIN
 
namespace alerts {
 
namespace impl {
struct SourceData {
    mutable std::atomic<bool> fired{false};
    std::atomic<std::chrono::steady_clock::time_point> stop_timepoint{{}};
 
    bool IsExpired() const;
};
 
void DumpMetric(utils::statistics::Writer& writer, const SourceData& m);
}  // namespace impl
 
/// @brief Alert source instance which is used to fire alerts via metrics for a specified amount of time.
///
/// To declare an alert:
/// @snippet core/src/logging/component.cpp  alert_declaration
///
/// Tu fire or to stop an alert:
/// @snippet core/src/logging/component.cpp  alert_usage
///
/// For non alert-metrics consider using utils::statistics::MetricTag.
class Source final {
public:
    static constexpr std::chrono::seconds kDefaultDuration{120};
    static constexpr std::chrono::hours kInfiniteDuration{24 * 365 * 10};  // In 10 years, someone should notice.
 
    /// Constructs an alert source instance that will be reported as non-zero "alerts." + std::string{name} metric
    /// in case of error
    explicit Source(std::string_view name);
 
    /// Fire alert for duration seconds.
    void FireAlert(utils::statistics::MetricsStorage& storage, std::chrono::seconds duration = kDefaultDuration) const;
 
    /// Stop fired alert
    void StopAlertNow(utils::statistics::MetricsStorage& storage) const;
 
private:
    utils::statistics::MetricTag<impl::SourceData> tag_;
};
 
}  // namespace alerts
 
USERVER_NAMESPACE_END