Line data    Source code

       1              : // Licensed under the Apache License, Version 2.0
       2              : // Copyright 2025, Michael Bushe, All rights reserved.
       3              : 
       4              : import 'package:dartastic_opentelemetry_api/dartastic_opentelemetry_api.dart';
       5              : 
       6              : import 'exemplar.dart';
       7              : 
       8              : /// Represents a metric data point, which consists of a value or set of values,
       9              : /// a set of attributes, and possibly exemplars.
      10              : ///
      11              : /// The type of value depends on the instrument type:
      12              : class MetricPoint<T> {
      13              :   /// The set of attributes associated with this metric point.
      14              :   final Attributes attributes;
      15              : 
      16              :   /// The start timestamp for this data point.
      17              :   final DateTime startTime;
      18              : 
      19              :   /// The end timestamp for this data point.
      20              :   final DateTime endTime;
      21              : 
      22              :   /// The value of the metric point. The type depends on the instrument type:
      23              :   /// - For counters: A single sum value as a [num]
      24              :   /// - For histograms: A [HistogramValue] object
      25              :   final T value;
      26              : 
      27              :   /// Optional exemplars for this data point.
      28              :   final List<Exemplar>? exemplars;
      29              : 
      30              :   /// Creates a new MetricPoint.
      31           19 :   MetricPoint({
      32              :     required this.attributes,
      33              :     required this.startTime,
      34              :     required this.endTime,
      35              :     required this.value,
      36              :     this.exemplars,
      37              :   });
      38              : 
      39              :   /// Creates a sum data point.
      40           11 :   factory MetricPoint.sum({
      41              :     required Attributes attributes,
      42              :     required DateTime startTime,
      43              :     required DateTime time,
      44              :     required T value,
      45              :     bool isMonotonic = true,
      46              :     List<Exemplar>? exemplars,
      47              :   }) {
      48           11 :     return MetricPoint(
      49              :       attributes: attributes,
      50              :       startTime: startTime,
      51              :       endTime: time,
      52              :       value: value,
      53              :       exemplars: exemplars,
      54              :     );
      55              :   }
      56              : 
      57              :   /// Creates a gauge data point.
      58            7 :   factory MetricPoint.gauge({
      59              :     required Attributes attributes,
      60              :     required DateTime startTime,
      61              :     required DateTime time,
      62              :     required T value,
      63              :     List<Exemplar>? exemplars,
      64              :   }) {
      65            7 :     return MetricPoint(
      66              :       attributes: attributes,
      67              :       startTime: startTime,
      68              :       endTime: time,
      69              :       value: value,
      70              :       exemplars: exemplars,
      71              :     );
      72              :   }
      73              : 
      74              :   /// Creates a histogram data point.
      75            0 :   factory MetricPoint.histogram({
      76              :     required Attributes attributes,
      77              :     required DateTime startTime,
      78              :     required DateTime time,
      79              :     required int count,
      80              :     required T sum,
      81              :     required List<int> counts,
      82              :     required List<double> boundaries,
      83              :     T? min,
      84              :     T? max,
      85              :     List<Exemplar>? exemplars,
      86              :   }) {
      87            0 :     return MetricPoint(
      88              :       attributes: attributes,
      89              :       startTime: startTime,
      90              :       endTime: time,
      91            0 :       value: HistogramValue(
      92            0 :         sum: (sum is num) ? sum : num.tryParse(sum.toString()) ?? 0.0,
      93              :         count: count,
      94              :         boundaries: boundaries,
      95              :         bucketCounts: counts,
      96            0 :         min: min is num
      97              :             ? min
      98              :             : min != null
      99            0 :                 ? num.tryParse(min.toString())
     100              :                 : null,
     101            0 :         max: max is num
     102              :             ? max
     103              :             : max != null
     104            0 :                 ? num.tryParse(max.toString())
     105              :                 : null,
     106              :       ) as T,
     107              :       exemplars: exemplars,
     108              :     );
     109              :   }
     110              : 
     111              :   /// Checks if this point has exemplars.
     112            6 :   bool get hasExemplars => exemplars != null && exemplars!.isNotEmpty;
     113              : 
     114              :   /// Creates a string representation of the value.
     115            1 :   String get valueAsString {
     116            2 :     if (value is HistogramValue) {
     117            1 :       final histValue = value as HistogramValue;
     118            3 :       return 'Histogram(sum: ${histValue.sum}, count: ${histValue.count})';
     119              :     } else {
     120            2 :       return value.toString();
     121              :     }
     122              :   }
     123              : 
     124              :   /// Gets this point as a histogram value. Will throw if this is not a histogram point.
     125            4 :   HistogramValue histogram() {
     126            8 :     if (value is! HistogramValue) {
     127            0 :       throw StateError('This is not a histogram point');
     128              :     }
     129            4 :     return value as HistogramValue;
     130              :   }
     131              : }
     132              : 
     133              : /// Represents the value of a histogram metric point.
     134              : class HistogramValue {
     135              :   /// The sum of all recorded values.
     136              :   final num sum;
     137              : 
     138              :   /// The count of all recorded values.
     139              :   final int count;
     140              : 
     141              :   /// The bucket boundaries.
     142              :   final List<double> boundaries;
     143              : 
     144              :   /// The counts in each bucket.
     145              :   final List<int> bucketCounts;
     146              : 
     147              :   /// The minimum recorded value (optional).
     148              :   final num? min;
     149              : 
     150              :   /// The maximum recorded value (optional).
     151              :   final num? max;
     152              : 
     153              :   /// Creates a new HistogramValue.
     154            7 :   HistogramValue({
     155              :     required this.sum,
     156              :     required this.count,
     157              :     required this.boundaries,
     158              :     required this.bucketCounts,
     159              :     this.min,
     160              :     this.max,
     161              :   });
     162              : }