Line data    Source code

       1              : // Copyright The OpenTelemetry Authors
       2              : // SPDX-License-Identifier: Apache-2.0
       3              : 
       4              : import '../../../dartastic_opentelemetry.dart';
       5              : 
       6              : /// BaseInstrument is the base class for all metric instruments.
       7              : ///
       8              : /// It provides common functionality for collecting metrics from instruments.
       9              : abstract class SDKInstrument {
      10              :   /// The name of the instrument
      11              :   String get name;
      12              : 
      13              :   /// The description of the instrument
      14              :   String? get description;
      15              : 
      16              :   /// The unit of the instrument
      17              :   String? get unit;
      18              : 
      19              :   /// Whether the instrument is enabled
      20              :   bool isEnabled();
      21              : 
      22              :   /// The meter that created this instrument
      23              :   APIMeter get meter;
      24              : 
      25              :   /// Collects metrics from this instrument
      26              :   ///
      27              :   /// This is called by metric readers to gather the current metrics
      28              :   List<Metric> collectMetrics();
      29              : }
      30              : 
      31              : /// An SDK asynchronous instrument that can receive observations from a
      32              : /// batch callback registered with [Meter.registerBatchCallback].
      33              : ///
      34              : /// A batch callback runs once per collection, before the instruments it
      35              : /// covers collect. Its observations are queued here and drained by the
      36              : /// instrument's own `collect()`, after the instrument's single-instrument
      37              : /// callbacks, so both sources land in the same collection cycle.
      38              : abstract class SDKObservableInstrument
      39              :     implements SDKInstrument, APIObservableInstrument {
      40              :   /// Queues a measurement observed by a batch callback for the next
      41              :   /// collection. The value is converted to the instrument's numeric type.
      42              :   void observeFromBatch(num value, Attributes? attributes);
      43              : }
      44              : 
      45              : /// Converts a [num] to the instrument's numeric type [T].
      46              : ///
      47              : /// Observable callbacks and batch callbacks report [num] values, while the
      48              : /// instrument's storage is typed; an `int` instrument truncates a double.
      49           10 : T castNum<T extends num>(num value) {
      50           19 :   if (T == int) return value.toInt() as T;
      51           16 :   if (T == double) return value.toDouble() as T;
      52              :   return value as T;
      53              : }