kcenon::network::metrics::histogram_snapshot Struct Reference

Immutable snapshot of histogram state for export. More...

#include <histogram.h>

Collaboration diagram for kcenon::network::metrics::histogram_snapshot:

Public Member Functions
auto	to_prometheus (const std::string &name) const -> std::string
	Export histogram in Prometheus format.
auto	to_json () const -> std::string
	Export histogram as JSON.

Public Attributes
uint64_t	count
	Total number of observations.
double	sum
	Sum of all observed values.
double	min_value
	Minimum observed value.
double	max_value
	Maximum observed value.
std::map< double, double >	percentiles
	Percentile -> value mapping.
std::vector< std::pair< double, uint64_t > >	buckets
	Boundary -> cumulative count.
std::map< std::string, std::string >	labels
	Additional metric labels.

Detailed Description

Immutable snapshot of histogram state for export.

Definition at line 59 of file histogram.h.

Member Function Documentation

to_json()

auto kcenon::network::metrics::histogram_snapshot::to_json ( ) const -> std::string

nodiscard

Export histogram as JSON.

Returns

JSON-formatted string

Definition at line 82 of file histogram.cpp.

{
    std::ostringstream oss;
    oss << std::fixed << std::setprecision(6);
 
    oss << "{";
    oss << "\"count\":" << count << ",";
    oss << "\"sum\":" << sum << ",";
    oss << "\"min\":" << min_value << ",";
    oss << "\"max\":" << max_value << ",";
 
    // Percentiles
    oss << "\"percentiles\":{";
    bool first = true;
    for (const auto& [p, v] : percentiles)
    {
        if (!first)
        {
            oss << ",";
        }
        oss << "\"" << p << "\":" << v;
        first = false;
    }
    oss << "},";
 
    // Buckets
    oss << "\"buckets\":[";
    first = true;
    for (const auto& [boundary, bucket_count] : buckets)
    {
        if (!first)
        {
            oss << ",";
        }
        oss << "{\"le\":";
        if (boundary == std::numeric_limits<double>::infinity())
        {
            oss << "\"+Inf\"";
        }
        else
        {
            oss << boundary;
        }
        oss << ",\"count\":" << bucket_count << "}";
        first = false;
    }
    oss << "],";
 
    // Labels
    oss << "\"labels\":{";
    first = true;
    for (const auto& [key, value] : labels)
    {
        if (!first)
        {
            oss << ",";
        }
        oss << "\"" << key << "\":\"" << value << "\"";
        first = false;
    }
    oss << "}";
 
    oss << "}";
 
    return oss.str();
}

References buckets, count, labels, max_value, min_value, percentiles, and sum.

to_prometheus()

auto kcenon::network::metrics::histogram_snapshot::to_prometheus ( const std::string & name ) const -> std::string

nodiscard

Export histogram in Prometheus format.

Parameters

name	Metric name

Returns

Prometheus-formatted string

Definition at line 19 of file histogram.cpp.

{
    std::ostringstream oss;
    oss << std::fixed << std::setprecision(6);
 
    // Build label string
    std::string label_str;
    if (!labels.empty())
    {
        std::ostringstream label_oss;
        label_oss << "{";
        bool first = true;
        for (const auto& [key, value] : labels)
        {
            if (!first)
            {
                label_oss << ",";
            }
            label_oss << key << "=\"" << value << "\"";
            first = false;
        }
        label_oss << "}";
        label_str = label_oss.str();
    }
 
    // Output bucket counts (cumulative)
    for (const auto& [boundary, bucket_count] : buckets)
    {
        oss << name << "_bucket{le=\"";
        if (boundary == std::numeric_limits<double>::infinity())
        {
            oss << "+Inf";
        }
        else
        {
            oss << boundary;
        }
        oss << "\"";
        if (!labels.empty())
        {
            oss << "," << label_str.substr(1, label_str.length() - 2);
        }
        oss << "} " << bucket_count << "\n";
    }
 
    // Output sum and count
    oss << name << "_sum";
    if (!labels.empty())
    {
        oss << label_str;
    }
    oss << " " << sum << "\n";
 
    oss << name << "_count";
    if (!labels.empty())
    {
        oss << label_str;
    }
    oss << " " << count << "\n";
 
    return oss.str();
}

Member Data Documentation

buckets

std::vector<std::pair<double, uint64_t> > kcenon::network::metrics::histogram_snapshot::buckets

Boundary -> cumulative count.

Definition at line 66 of file histogram.h.

Referenced by kcenon::network::metrics::sliding_histogram::aggregate(), kcenon::network::metrics::histogram::snapshot(), and to_json().

count

uint64_t kcenon::network::metrics::histogram_snapshot::count

Total number of observations.

Definition at line 61 of file histogram.h.

Referenced by kcenon::network::metrics::sliding_histogram::aggregate(), kcenon::network::metrics::histogram::snapshot(), and to_json().

labels

std::map<std::string, std::string> kcenon::network::metrics::histogram_snapshot::labels

Additional metric labels.

Definition at line 67 of file histogram.h.

Referenced by kcenon::network::metrics::histogram::snapshot(), and to_json().

max_value

double kcenon::network::metrics::histogram_snapshot::max_value

Maximum observed value.

Definition at line 64 of file histogram.h.

Referenced by kcenon::network::metrics::sliding_histogram::aggregate(), kcenon::network::metrics::histogram::snapshot(), and to_json().

min_value

double kcenon::network::metrics::histogram_snapshot::min_value

Minimum observed value.

Definition at line 63 of file histogram.h.

Referenced by kcenon::network::metrics::sliding_histogram::aggregate(), kcenon::network::metrics::histogram::snapshot(), and to_json().

percentiles

std::map<double, double> kcenon::network::metrics::histogram_snapshot::percentiles

Percentile -> value mapping.

Definition at line 65 of file histogram.h.

Referenced by kcenon::network::metrics::sliding_histogram::aggregate(), kcenon::network::metrics::histogram::snapshot(), and to_json().

sum

double kcenon::network::metrics::histogram_snapshot::sum

Sum of all observed values.

Definition at line 62 of file histogram.h.

Referenced by kcenon::network::metrics::sliding_histogram::aggregate(), kcenon::network::metrics::histogram::snapshot(), and to_json().

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The documentation for this struct was generated from the following files:

• include/kcenon/network/detail/metrics/histogram.h
• src/metrics/histogram.cpp