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 '../data/metric.dart';
       7              : import '../data/metric_point.dart';
       8              : import '../meter.dart';
       9              : import '../storage/sum_storage.dart';
      10              : import 'base_instrument.dart';
      11              : 
      12              : /// UpDownCounter is a synchronous instrument that records additive values.
      13              : ///
      14              : /// An UpDownCounter is used to measure a value that increases and decreases.
      15              : /// For example, the number of active requests, queue size, pool size.
      16              : class UpDownCounter<T extends num>
      17              :     implements APIUpDownCounter<T>, SDKInstrument {
      18              :   /// The underlying API UpDownCounter.
      19              :   final APIUpDownCounter<T> _apiCounter;
      20              : 
      21              :   /// The Meter that created this UpDownCounter.
      22              :   final Meter _meter;
      23              : 
      24              :   /// Storage for accumulating up-down counter measurements.
      25              :   final SumStorage<T> _storage = SumStorage<T>(isMonotonic: false);
      26              : 
      27              :   /// Creates a new UpDownCounter instance.
      28            4 :   UpDownCounter({
      29              :     required APIUpDownCounter<T> apiCounter,
      30              :     required Meter meter,
      31              :   })  : _apiCounter = apiCounter,
      32              :         _meter = meter {
      33              :     // Register this instrument with the meter provider
      34           20 :     _meter.provider.registerInstrument(_meter.name, this);
      35              :   }
      36              : 
      37            4 :   @override
      38            8 :   String get name => _apiCounter.name;
      39              : 
      40            2 :   @override
      41            4 :   String? get unit => _apiCounter.unit;
      42              : 
      43            2 :   @override
      44            4 :   String? get description => _apiCounter.description;
      45              : 
      46            1 :   @override
      47            2 :   bool get enabled => _meter.enabled;
      48              : 
      49            4 :   @override
      50            4 :   APIMeter get meter => _meter;
      51              : 
      52            1 :   @override
      53              :   bool get isCounter => false;
      54              : 
      55            1 :   @override
      56              :   bool get isUpDownCounter => true;
      57              : 
      58            1 :   @override
      59              :   bool get isGauge => false;
      60              : 
      61            1 :   @override
      62              :   bool get isHistogram => false;
      63              : 
      64            3 :   @override
      65              :   void add(T value, [Attributes? attributes]) {
      66              :     // First use the API implementation (no-op by default)
      67            6 :     _apiCounter.add(value, attributes);
      68              : 
      69              :     // In the SDK, we only check the meter's enabled state
      70            6 :     if (!_meter.enabled) return;
      71              : 
      72              :     // Record the measurement in our storage
      73            6 :     _storage.record(value, attributes);
      74              :   }
      75              : 
      76            1 :   @override
      77              :   void addWithMap(T value, Map<String, Object> attributeMap) {
      78              :     // Just convert to Attributes and call add
      79              :     final attributes =
      80            2 :         attributeMap.isEmpty ? null : attributeMap.toAttributes();
      81            1 :     add(value, attributes);
      82              :   }
      83              : 
      84              :   /// Gets the current value of the counter for a specific set of attributes.
      85              :   /// If no attributes are provided, returns the sum of all values across all attributes.
      86            3 :   T getValue([Attributes? attributes]) {
      87            6 :     return _storage.getValue(attributes);
      88              :   }
      89              : 
      90              :   /// Gets the current points for this counter.
      91              :   /// This is used by the SDK to collect metrics.
      92            1 :   List<MetricPoint<T>> collectPoints() {
      93            2 :     return _storage.collectPoints();
      94              :   }
      95              : 
      96            1 :   @override
      97              :   List<Metric> collectMetrics() {
      98            2 :     if (!enabled) return [];
      99              : 
     100              :     // Get the points from storage
     101            1 :     final points = collectPoints();
     102              : 
     103            1 :     if (points.isEmpty) return [];
     104              : 
     105              :     // Create a metric with the collected points
     106            1 :     final metric = Metric(
     107            1 :       name: name,
     108            1 :       description: description,
     109            1 :       unit: unit,
     110              :       type: MetricType.sum, // UpDownCounter is still a sum, just not monotonic
     111              :       points: points,
     112              :     );
     113              : 
     114            1 :     return [metric];
     115              :   }
     116              : 
     117              :   /// Resets the counter. This is only used for Delta temporality.
     118            2 :   void reset() {
     119            4 :     _storage.reset();
     120              :   }
     121              : }