Trigger based on rate of change of values. More...

#include <alert_triggers.h>

Inheritance diagram for kcenon::monitoring::rate_of_change_trigger:

Collaboration diagram for kcenon::monitoring::rate_of_change_trigger:

Classes
struct	sample

Public Types
enum class	rate_direction { increasing , decreasing , either }
	Direction of rate change to monitor. More...

Public Member Functions
	rate_of_change_trigger (double rate_threshold, std::chrono::milliseconds window, rate_direction direction=rate_direction::either, size_t min_samples=2)
	Construct a rate of change trigger.

bool	evaluate (double value) const override
	Evaluate the trigger condition.

std::string	type_name () const override
	Get trigger type name.

std::string	description () const override
	Get human-readable description.

void	reset ()
	Clear accumulated samples.

Public Member Functions inherited from kcenon::monitoring::alert_trigger
virtual	~alert_trigger ()=default

Private Member Functions
double	calculate_rate () const

Private Attributes
double	rate_threshold_

std::chrono::milliseconds	window_

rate_direction	direction_

size_t	min_samples_

std::mutex	mutex_

std::deque< sample >	samples_

Detailed Description

Trigger based on rate of change of values.

Monitors how quickly a metric value is changing and triggers when the rate exceeds a threshold. Useful for detecting rapid increases or decreases in metrics.

Definition at line 241 of file alert_triggers.h.

Member Enumeration Documentation

◆ rate_direction

enum class kcenon::monitoring::rate_of_change_trigger::rate_direction

strong

Direction of rate change to monitor.

Enumerator
increasing	Positive rate of change.
decreasing	Negative rate of change.
either	Absolute rate of change.

Examples: /home/runner/work/monitoring_system/monitoring_system/include/kcenon/monitoring/alert/alert_triggers.h.

Definition at line 247 of file alert_triggers.h.

                              {
        increasing,     
        decreasing,     
        either          
    };

Constructor & Destructor Documentation

◆ rate_of_change_trigger()

kcenon::monitoring::rate_of_change_trigger::rate_of_change_trigger	(	double	rate_threshold,
		std::chrono::milliseconds	window,
		rate_direction	direction = rate_direction::either,
		size_t	min_samples = 2 )

inline

Construct a rate of change trigger.

Parameters

rate_threshold	Rate threshold per time window
window	Time window for rate calculation
direction	Direction to monitor
min_samples	Minimum samples before triggering

Examples: /home/runner/work/monitoring_system/monitoring_system/include/kcenon/monitoring/alert/alert_triggers.h.

Definition at line 260 of file alert_triggers.h.

        : rate_threshold_(rate_threshold)
        , window_(window)
        , direction_(direction)
        , min_samples_(min_samples) {}

Member Function Documentation

◆ calculate_rate()

double kcenon::monitoring::rate_of_change_trigger::calculate_rate ( ) const

inlineprivate

Examples: /home/runner/work/monitoring_system/monitoring_system/include/kcenon/monitoring/alert/alert_triggers.h.

Definition at line 332 of file alert_triggers.h.

                                  {
        if (samples_.size() < 2) {
            return 0.0;
        }
 
        // Use linear regression for smoother rate calculation
        double sum_x = 0.0, sum_y = 0.0, sum_xy = 0.0, sum_xx = 0.0;
        auto base_time = samples_.front().timestamp;
 
        for (const auto& s : samples_) {
            double x = std::chrono::duration<double, std::milli>(
                s.timestamp - base_time).count();
            double y = s.value;
            sum_x += x;
            sum_y += y;
            sum_xy += x * y;
            sum_xx += x * x;
        }
 
        double n = static_cast<double>(samples_.size());
        double denominator = n * sum_xx - sum_x * sum_x;
 
        if (std::abs(denominator) < 1e-10) {
            return 0.0;
        }
 
        // Slope is rate of change per millisecond
        double slope = (n * sum_xy - sum_x * sum_y) / denominator;
 
        // Convert to rate per window
        return slope * static_cast<double>(window_.count());
    }

References samples_, and window_.

Referenced by evaluate().

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◆ description()

std::string kcenon::monitoring::rate_of_change_trigger::description ( ) const

inlineoverridevirtual

Get human-readable description.

Returns: Description string

Implements kcenon::monitoring::alert_trigger.

Examples: /home/runner/work/monitoring_system/monitoring_system/include/kcenon/monitoring/alert/alert_triggers.h.

Definition at line 307 of file alert_triggers.h.

                                           {
        std::string dir_str;
        switch (direction_) {
            case rate_direction::increasing: dir_str = "increase"; break;
            case rate_direction::decreasing: dir_str = "decrease"; break;
            case rate_direction::either: dir_str = "change"; break;
        }
        return dir_str + " rate > " + std::to_string(rate_threshold_) +
               " per " + std::to_string(window_.count()) + "ms";
    }

References decreasing, direction_, either, increasing, rate_threshold_, and window_.

◆ evaluate()

bool kcenon::monitoring::rate_of_change_trigger::evaluate ( double value ) const

inlineoverridevirtual

Evaluate the trigger condition.

Parameters

value Current metric value

Returns: True if trigger condition is met

Implements kcenon::monitoring::alert_trigger.

Examples: /home/runner/work/monitoring_system/monitoring_system/include/kcenon/monitoring/alert/alert_triggers.h.

Definition at line 269 of file alert_triggers.h.

                                               {
        auto now = std::chrono::steady_clock::now();
 
        std::lock_guard<std::mutex> lock(mutex_);
 
        // Add new sample
        samples_.push_back({value, now});
 
        // Remove old samples outside window
        auto cutoff = now - window_;
        while (!samples_.empty() && samples_.front().timestamp < cutoff) {
            samples_.pop_front();
        }
 
        // Need minimum samples to calculate rate
        if (samples_.size() < min_samples_) {
            return false;
        }
 
        // Calculate rate of change
        double rate = calculate_rate();
 
        switch (direction_) {
            case rate_direction::increasing:
                return rate > rate_threshold_;
            case rate_direction::decreasing:
                return rate < -rate_threshold_;
            case rate_direction::either:
                return std::abs(rate) > rate_threshold_;
            default:
                return false;
        }
    }

References calculate_rate(), decreasing, direction_, either, increasing, min_samples_, mutex_, rate_threshold_, samples_, and window_.

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◆ reset()

void kcenon::monitoring::rate_of_change_trigger::reset ( )

inline

Clear accumulated samples.

Examples: /home/runner/work/monitoring_system/monitoring_system/include/kcenon/monitoring/alert/alert_triggers.h.

Definition at line 321 of file alert_triggers.h.

                 {
        std::lock_guard<std::mutex> lock(mutex_);
        samples_.clear();
    }

References mutex_, and samples_.

◆ type_name()

std::string kcenon::monitoring::rate_of_change_trigger::type_name ( ) const

inlineoverridevirtual

Get trigger type name.

Returns: Type name string

Implements kcenon::monitoring::alert_trigger.

Examples: /home/runner/work/monitoring_system/monitoring_system/include/kcenon/monitoring/alert/alert_triggers.h.

Definition at line 303 of file alert_triggers.h.

                                         {
        return "rate_of_change";
    }

Member Data Documentation

◆ direction_

rate_direction kcenon::monitoring::rate_of_change_trigger::direction_

private

Examples: /home/runner/work/monitoring_system/monitoring_system/include/kcenon/monitoring/alert/alert_triggers.h.

Definition at line 367 of file alert_triggers.h.

Referenced by description(), and evaluate().

◆ min_samples_

size_t kcenon::monitoring::rate_of_change_trigger::min_samples_

private

Examples: /home/runner/work/monitoring_system/monitoring_system/include/kcenon/monitoring/alert/alert_triggers.h.

Definition at line 368 of file alert_triggers.h.

Referenced by evaluate().

◆ mutex_

std::mutex kcenon::monitoring::rate_of_change_trigger::mutex_

mutableprivate

Examples: /home/runner/work/monitoring_system/monitoring_system/include/kcenon/monitoring/alert/alert_triggers.h.

Definition at line 370 of file alert_triggers.h.

Referenced by evaluate(), and reset().

◆ rate_threshold_

double kcenon::monitoring::rate_of_change_trigger::rate_threshold_

private

Examples: /home/runner/work/monitoring_system/monitoring_system/include/kcenon/monitoring/alert/alert_triggers.h.

Definition at line 365 of file alert_triggers.h.

Referenced by description(), and evaluate().

◆ samples_

std::deque<sample> kcenon::monitoring::rate_of_change_trigger::samples_

mutableprivate

Examples: /home/runner/work/monitoring_system/monitoring_system/include/kcenon/monitoring/alert/alert_triggers.h.

Definition at line 371 of file alert_triggers.h.

Referenced by calculate_rate(), evaluate(), and reset().

◆ window_

std::chrono::milliseconds kcenon::monitoring::rate_of_change_trigger::window_

private

Examples: /home/runner/work/monitoring_system/monitoring_system/include/kcenon/monitoring/alert/alert_triggers.h.

Definition at line 366 of file alert_triggers.h.

Referenced by calculate_rate(), description(), and evaluate().

The documentation for this class was generated from the following file:

include/kcenon/monitoring/alert/alert_triggers.h

Classes

Public Types

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Member Enumeration Documentation

◆ rate_direction

Constructor & Destructor Documentation

◆ rate_of_change_trigger()

Member Function Documentation

◆ calculate_rate()

◆ description()

◆ evaluate()

◆ reset()

◆ type_name()

Member Data Documentation

◆ direction_

◆ min_samples_

◆ mutex_

◆ rate_threshold_

◆ samples_

◆ window_