Line data    Source code

       1              : // Copyright The OpenTelemetry Authors
       2              : // SPDX-License-Identifier: Apache-2.0
       3              : 
       4              : import 'dart:async';
       5              : 
       6              : import 'data/metric_data.dart';
       7              : 
       8              : /// MetricExporter is responsible for sending metrics to a backend.
       9              : abstract class MetricExporter {
      10              :   /// Export a batch of metrics to the backend.
      11              :   ///
      12              :   /// Returns true if the export was successful, false otherwise.
      13              :   Future<bool> export(MetricData data);
      14              : 
      15              :   /// Force flush any pending metrics.
      16              :   ///
      17              :   /// Returns true if the flush was successful, false otherwise.
      18              :   Future<bool> forceFlush();
      19              : 
      20              :   /// Shutdown the exporter.
      21              :   ///
      22              :   /// This should cleanup any resources and perform final exports.
      23              :   /// Returns true if the shutdown was successful, false otherwise.
      24              :   Future<bool> shutdown();
      25              : }
      26              : 
      27              : /// ConsoleMetricExporter is a simple exporter that prints metrics to the console.
      28              : class ConsoleMetricExporter implements MetricExporter {
      29              :   /// Whether the exporter has been shut down.
      30              :   bool _isShutdown = false;
      31              : 
      32            0 :   @override
      33              :   Future<bool> export(MetricData data) async {
      34            0 :     if (_isShutdown) {
      35            0 :       print('ConsoleMetricExporter: Cannot export after shutdown');
      36              :       return false;
      37              :     }
      38              : 
      39            0 :     print('ConsoleMetricExporter: Exporting ${data.metrics.length} metrics:');
      40            0 :     for (final metric in data.metrics) {
      41            0 :       print(
      42            0 :           '  - ${metric.name} (${metric.unit ?? "no unit"}): ${metric.description ?? ""}');
      43            0 :       for (final point in metric.points) {
      44            0 :         final value = point.valueAsString;
      45            0 :         print('    - Value: $value, Attributes: ${point.attributes}');
      46            0 :         if (point.hasExemplars) {
      47            0 :           print('      Exemplars: ${point.exemplars?.length}');
      48              :         }
      49              :       }
      50              :     }
      51              : 
      52              :     return true;
      53              :   }
      54              : 
      55            0 :   @override
      56              :   Future<bool> forceFlush() async {
      57              :     // No-op for console exporter
      58              :     return true;
      59              :   }
      60              : 
      61            0 :   @override
      62              :   Future<bool> shutdown() async {
      63            0 :     _isShutdown = true;
      64              :     return true;
      65              :   }
      66              : }