Line data    Source code

       1              : // Copyright The OpenTelemetry Authors
       2              : // SPDX-License-Identifier: Apache-2.0
       3              : 
       4              : import 'package:dartastic_opentelemetry_api/dartastic_opentelemetry_api.dart';
       5              : 
       6              : import '../data/metric.dart';
       7              : import '../data/metric_point.dart';
       8              : import '../meter.dart';
       9              : import '../storage/histogram_storage.dart';
      10              : import 'base_instrument.dart';
      11              : 
      12              : /// Histogram is a synchronous instrument that records a distribution of values.
      13              : ///
      14              : /// A Histogram is used to measure a distribution of values, such as request durations,
      15              : /// response sizes, or latencies.
      16              : class Histogram<T extends num> implements APIHistogram<T>, SDKInstrument {
      17              :   /// The underlying API Histogram.
      18              :   final APIHistogram<T> _apiHistogram;
      19              : 
      20              :   /// The Meter that created this Histogram.
      21              :   final Meter _meter;
      22              : 
      23              :   /// Storage for accumulating histogram measurements.
      24              :   final HistogramStorage<T> _storage;
      25              : 
      26              :   /// Creates a new Histogram instance.
      27            7 :   Histogram({
      28              :     required APIHistogram<T> apiHistogram,
      29              :     required Meter meter,
      30              :     List<double>? boundaries,
      31              :   })  : _apiHistogram = apiHistogram,
      32              :         _meter = meter,
      33            7 :         _storage = HistogramStorage(
      34              :           boundaries: boundaries ?? _defaultBoundaries,
      35              :           recordMinMax: true,
      36           14 :           exemplarFilter: meter.provider.exemplarFilter,
      37              :         ) {
      38              :     // Register this instrument with the meter provider
      39           35 :     _meter.provider.registerInstrument(_meter.name, this);
      40              :   }
      41              : 
      42              :   /// Default bucket boundaries.
      43              :   static const List<double> _defaultBoundaries = [
      44              :     0,
      45              :     5,
      46              :     10,
      47              :     25,
      48              :     50,
      49              :     75,
      50              :     100,
      51              :     250,
      52              :     500,
      53              :     750,
      54              :     1000,
      55              :     2500,
      56              :     5000,
      57              :     7500,
      58              :     10000,
      59              :   ];
      60              : 
      61            7 :   @override
      62           14 :   String get name => _apiHistogram.name;
      63              : 
      64            3 :   @override
      65            6 :   String? get unit => _apiHistogram.unit;
      66              : 
      67            3 :   @override
      68            6 :   String? get description => _apiHistogram.description;
      69              : 
      70            4 :   @override
      71            8 :   bool isEnabled() => _meter.isEnabled();
      72              : 
      73            7 :   @override
      74            7 :   APIMeter get meter => _meter;
      75              : 
      76            1 :   @override
      77            2 :   List<double>? get boundaries => _apiHistogram.boundaries;
      78              : 
      79            1 :   @override
      80              :   bool get isCounter => false;
      81              : 
      82            1 :   @override
      83              :   bool get isUpDownCounter => false;
      84              : 
      85            1 :   @override
      86              :   bool get isGauge => false;
      87              : 
      88            1 :   @override
      89              :   bool get isHistogram => true;
      90              : 
      91            4 :   @override
      92              :   void record(T value, [Attributes? attributes]) {
      93              :     // First use the API implementation (no-op by default)
      94            8 :     _apiHistogram.record(value, attributes);
      95              : 
      96              :     // Only record if enabled
      97            4 :     if (!isEnabled()) return;
      98              : 
      99              :     // Record the measurement in our storage
     100           12 :     _storage.record(value, attributes, Context.current);
     101              :   }
     102              : 
     103            1 :   @override
     104              :   void recordWithMap(T value, Map<String, Object> attributeMap) {
     105              :     // Just convert to Attributes and call record
     106              :     final attributes =
     107            2 :         attributeMap.isEmpty ? null : attributeMap.toAttributes();
     108            1 :     record(value, attributes);
     109              :   }
     110              : 
     111              :   /// Gets the current histogram value for the given attributes.
     112              :   /// If no attributes are provided, returns the histogram value for the null/empty attribute set.
     113            2 :   HistogramValue getValue([Attributes? attributes]) {
     114            4 :     return _storage.getValue(attributes);
     115              :   }
     116              : 
     117              :   /// Gets the current points for this histogram.
     118              :   /// This is used by the SDK to collect metrics.
     119            3 :   List<MetricPoint<HistogramValue>> collectPoints() {
     120            6 :     return _storage.collectPoints();
     121              :   }
     122              : 
     123            3 :   @override
     124              :   List<Metric> collectMetrics() {
     125            4 :     if (!isEnabled()) return [];
     126              : 
     127              :     // Get the points from storage
     128            3 :     final points = collectPoints();
     129              : 
     130            3 :     if (points.isEmpty) return [];
     131              : 
     132              :     // Create a metric with the collected points
     133            3 :     final metric = Metric(
     134            3 :       name: name,
     135            3 :       description: description,
     136            3 :       unit: unit,
     137              :       type: MetricType.histogram,
     138              :       points: points,
     139              :     );
     140              : 
     141            3 :     return [metric];
     142              :   }
     143              : 
     144              :   /// Resets the histogram. This is only used for Delta temporality.
     145            1 :   void reset() {
     146            2 :     _storage.reset();
     147              :   }
     148              : }