Use new UseOtlpExporter method from the OTEL library

[davidfowl]

open-telemetry/opentelemetry-dotnet#5400

[DamianEdwards]

Currently available in 1.8.0-beta.1

This would be an update to the templates IIUC, specifically the ServiceDefaults project. We should wait until there's a stable release before integrating I think.

[CodeBlanch]

Really the whole point of putting out that beta was for Aspire to take it for a spin and provide feedback 🤣 Please do!

Here's the things in 1.8.0-beta.1 which should be of interest to Aspire:

• Addition of UseOtlpExporter
• Removal of OTEL_DOTNET_EXPERIMENTAL_OTLP_EMIT_EXCEPTION_LOG_ATTRIBUTES
• Addition of OTEL_DOTNET_EXPERIMENTAL_OTLP_ENABLE_INMEMORY_RETRY

This one didn't make the first beta but will come in the next drop: open-telemetry/opentelemetry-dotnet#5448

[DamianEdwards]

@CodeBlanch great! I'll try it out to get a sense of how it would impact our experience, thanks.

[DamianEdwards]

OK so yeah, this allows us to simplify the ServiceDefaults code to enable OTLP quite a bit:

private static IHostApplicationBuilder AddOpenTelemetryExporters(this IHostApplicationBuilder builder)
{
+    builder.Services.AddOpenTelemetry()
+       // Enable OTLP exporter for all telemetry based on defaults and environment variables
+       .UseOtlpExporter();
+       // Uncomment the following lines to enable the Prometheus exporter (requires the OpenTelemetry.Exporter.Prometheus.AspNetCore package)
+       //.WithMetrics(metrics => metrics.AddPrometheusExporter());
    
-    var useOtlpExporter = !string.IsNullOrWhiteSpace(builder.Configuration["OTEL_EXPORTER_OTLP_ENDPOINT"]);
    
-    if (useOtlpExporter)
-    {
-        builder.Services.Configure<OpenTelemetryLoggerOptions>(logging => logging.AddOtlpExporter());
-        builder.Services.ConfigureOpenTelemetryMeterProvider(metrics => metrics.AddOtlpExporter());
-        builder.Services.ConfigureOpenTelemetryTracerProvider(tracing => tracing.AddOtlpExporter());
-    }

-    // Uncomment the following lines to enable the Prometheus exporter (requires the OpenTelemetry.Exporter.Prometheus.AspNetCore package)
-    // builder.Services.AddOpenTelemetry()
-    //    .WithMetrics(metrics => metrics.AddPrometheusExporter());
    
    // Uncomment the following lines to enable the Azure Monitor exporter (requires the Azure.Monitor.OpenTelemetry.AspNetCore package)
    //if (!string.IsNullOrEmpty(builder.Configuration["APPLICATIONINSIGHTS_CONNECTION_STRING"]))
    //{
    //    builder.Services.AddOpenTelemetry()
    //       .UseAzureMonitor();
    //}

     return builder;
}

[DamianEdwards]

I'll move this to preview.6 as I'm not expecting we're going to get a stable version of the package with this change in time for preview.5

[DamianEdwards]

rc.1 is out now https://github.com/open-telemetry/opentelemetry-dotnet/releases/tag/core-1.8.0-rc.1

[CodeBlanch]

@DamianEdwards Does Aspire use something like appSettings.Development.json? Asking because FYI using rc.1 you could remove this...

aspire/src/Aspire.ProjectTemplates/templates/aspire-servicedefaults/Extensions.cs

Lines 58 to 62 in 93a1efb

	if (builder.Environment.IsDevelopment())
	{
	// We want to view all traces in development
	tracing.SetSampler(new AlwaysOnSampler());
	}

...and do it via config:

appSettings.Development.json

{
   "OTEL_TRACES_SAMPLER": "always_on"
}

If you wanted to 😄

[davidfowl]

We can set environment variables.

cc @JamesNK

[samsp-msft]

#3316

[CodeBlanch]

Stable 1.8.0 OTel packages should be on Nuget now.

One late change to pay attention to: https://github.com/open-telemetry/opentelemetry-dotnet/blob/fb74013d644d56f44ef89dd57358947bd9f68345/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/CHANGELOG.md?plain=1#L17-L22

The envar key/value for enabling in-memory retry changed for stable.

[davidfowl]

Done in #3359

[martincostello]

FYI I've found a bunch of trim warnings related to this: open-telemetry/opentelemetry-dotnet#5518 (comment)