77 lines
2.7 KiB
Markdown
77 lines
2.7 KiB
Markdown
# Extending the OpenTelemetry .NET SDK
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* [Building your own exporter](#exporter)
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* [Building your own reader](#reader)
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* [Building your own exemplar](#exemplar)
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* [References](#references)
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## Exporter
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OpenTelemetry .NET SDK has provided the following built-in metric exporters:
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* [InMemory](../../../src/OpenTelemetry.Exporter.InMemory/README.md)
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* [Console](../../../src/OpenTelemetry.Exporter.Console/README.md)
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* [OpenTelemetryProtocol](../../../src/OpenTelemetry.Exporter.OpenTelemetryProtocol/README.md)
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* [Prometheus](../../../src/OpenTelemetry.Exporter.Prometheus/README.md)
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Custom exporters can be implemented to send telemetry data to places which are
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not covered by the built-in exporters:
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* Exporters should derive from `OpenTelemetry.BaseExporter<Metric>` (which
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belongs to the [OpenTelemetry](../../../src/OpenTelemetry/README.md) package)
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and implement the `Export` method.
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* Exporters can optionally implement the `OnShutdown` method.
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* Exporters should not throw exceptions from `Export` and
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`OnShutdown`.
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* Exporters are responsible for any retry logic needed by the scenario. The SDK
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does not implement any retry logic.
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* Exporters should avoid generating telemetry and causing live-loop, this can be
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done via `OpenTelemetry.SuppressInstrumentationScope`.
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* Exporters receives a batch of `Metric`, and each `Metric`
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can contain 1 or more `MetricPoint`s.
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The exporter should perform all actions (e.g. serializing etc.) with
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the `Metric`s and `MetricsPoint`s in the batch before returning control from
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`Export`, once the control is returned, the exporter can no longer make any
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assumptions about the state of the batch or anything inside it.
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* Exporters should use `ParentProvider.GetResource()` to get the `Resource`
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associated with the provider.
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```csharp
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class MyExporter : BaseExporter<Metric>
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{
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public override ExportResult Export(in Batch<Metric> batch)
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{
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using var scope = SuppressInstrumentationScope.Begin();
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foreach (var metric in batch)
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{
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Console.WriteLine($"Export: {metric.metric}");
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foreach (ref readonly var metricPoint in metric.GetMetricPoints())
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{
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Console.WriteLine($"Export: {metricPoint.StartTime}");
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}
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}
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return ExportResult.Success;
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}
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}
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```
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A demo exporter which simply writes metric name, metric point start time
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and tags to the console is shown [here](./MyExporter.cs).
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Apart from the exporter itself, you should also provide extension methods as
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shown [here](./MyExporterExtensions.cs). This allows users to add the Exporter
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to the `MeterProvider` as shown in the example [here](./Program.cs).
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## Reader
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Not supported.
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## Exemplar
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Not supported.
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## References
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