Is It Allowed to Add Multiple MeterProvider in OpenTelemetry .NET

[huapeng-zhang]

I have a question regarding the use of multiple MeterProvider instances in OpenTelemetry .NET. Specifically, I want to add multiple MeterProvider instances, each with different meters and use different exporters.

Here is the example of my use case:
`
var meterProvider1 = Sdk.CreateMeterProviderBuilder()
.AddMeter(meterName1)
.AddConsoleExporter()
.Build();

var meterProvider2 = Sdk.CreateMeterProviderBuilder()
.AddMeter(meterName2)
.AddConsoleExporter()
.Build();
`

Is it allowed to configure multiple MeterProvider instances in this manner? Are there any potential issues or limitations I should be aware of when implementing this approach?

[cijothomas]

Yes it is allowed. Each MeterProvider creates a PeriodicReader, which creates a new Thread.. If you don't mind that extra need, this is totally fine.
(Make you don't end up creating a MeterProvider per metric emission. They are fairly big objects, so create-once-re-use-till-end should be followed, but having multiple is just fine.)

[huapeng-zhang]

Thanks @cijothomas for quick response.

I have a follow-up question regarding the creation of multiple MeterProvider instances through Dependency Injection (DI). According to the code comments, it seems that only a single MeterProvider is created, even when the method OpenTelemetryBuilder AddOpenTelemetry(this IServiceCollection services) is called multiple times.

Code Example

// Try to create the first MeterProviderBuilder.
services.AddOpenTelemetry()
.WithMetrics(delegate (MeterProviderBuilder builder)
{
builder
.AddMeter(meterName1)
.AddConsoleExporter();
}
// Try to create the second MeterProviderBuilder
// Actually only one MeterProvider will be created.
services.AddOpenTelemetry()
.WithMetrics(delegate (MeterProviderBuilder builder)
{
builder
.AddMeter(meterName2)
.AddConsoleExporter();
}

[cijothomas]

The DI based method only creates one provider. If needing multiple, stick with Sdk.Create style APIs.