Instrumentation.StackExchangeRedis Should Resolve IConnectionMultiplexer from DI

Feature Request

I have registered IConnectionMultiplexer in my DI container for health checks, a Redis implementation of IDistributedCache and other reasons. It would be nice if OpenTelemetry.Instrumentation.StackExchangeRedis contained an overload for the AddRedisInstrumentation function that allows you to resolve IConnectionMultiplexer from DI:

public static TracerProviderBuilder AddRedisInstrumentation(
    this TracerProviderBuilder builder,
    Func<IConnectionMultiplexer, IServiceBuilder> getConnection,
    Action<StackExchangeRedisCallsInstrumentationOptions> configureOptions = null);

Another overload that assumes that IConnectionMultiplexer is registered in DI would also be helpful:

public static TracerProviderBuilder AddRedisInstrumentation(
    this TracerProviderBuilder builder,
    Action<StackExchangeRedisCallsInstrumentationOptions> configureOptions = null);

Is your feature request related to a problem?

I have to create a new connection specifically for Open Telemetry.

Describe the solution you’d like:

I would like to reuse the connection I’m using elsewhere.

[evilpilaf]

@trejjam it’s still possible, just a bit different, for rc4 you can do this:

services.AddOpenTelemetryTracing(builder => {
    builder.Configure((provider, b) => {
        var connectionMultiplexer = provider.GetRequiredService<IConnectionMultiplexer>();
        b.AddRedisInstrumentation(connectionMultiplexer);
    });
});

Though I agree it’s a bit more cumbersome and the previous approach was better.

[CodeBlanch]

We’re trying to do something here! It is tricky because we’re supporting .NET Framework where IServiceCollection probably isn’t being used. The reason the API changed is we introduced this thing called IDeferredTracerProviderBuilder. Right now it is part of SDK. We’re trying to figure out how to get it into API. Once it is there, it should be possible to add an extension like this in OpenTelemetry.Instrumentation.StackExchangeRedis:

        public static TracerProviderBuilder AddRedisInstrumentation(
            this TracerProviderBuilder builder,
            Action<StackExchangeRedisCallsInstrumentationOptions> configureOptions = null)
        {
            if (!(builder is IDeferredTracerProviderBuilder deferredTracerProviderBuilder))
            {
                throw new NotSupportedException("IConnectionMultiplexer could not be resolved automatically.");
            }

            return deferredTracerProviderBuilder.Configure((sp, builder) =>
            {
                StackExchangeRedisCallsInstrumentationOptions options = sp.GetOptions<StackExchangeRedisCallsInstrumentationOptions>();
                configureOptions?.Invoke(options);

                builder
                    .AddInstrumentation(() => new StackExchangeRedisCallsInstrumentation(
                        sp.GetService<IConnectionMultiplexer>() ?? throw new InvalidOperationException("IConnectionMultiplexer could not be found on IServiceProvider."),
                        options))
                    .AddSource(StackExchangeRedisCallsInstrumentation.ActivitySourceName);
            });
        }

That would allow it to automatically resolve IConnectionMultiplexer (& options) automatically through the IServiceProvider and users won’t need to use the more cumbersome syntax shown above!