Opentelemetry-dotnet: StackExchange.Redis instrumentation not working when using ConfigureServices(IServiceCollection services)

Created on 16 Nov 2020 · 4Comments · Source: open-telemetry/opentelemetry-dotnet

Bug Report

List of NuGet packages and version that you are using (e.g. OpenTelemetry 0.4.0-beta.2):

OpenTelemetry 0.8.0-beta.1
OpenTelemetry.Exporter.Console 0.8.0-beta.1
OpenTelemetry.Extensions.Hosting 0.8.0-beta.1
OpenTelemetry.Instrumentation.AspNetCore 0.8.0-beta.1
OpenTelemetry.Instrumentation.Http 0.8.0-beta.1
OpenTelemetry.Instrumentation.StackExchangeRedis 0.8.0-beta.1

Runtime version (e.g. net461, net48, netcoreapp2.1, netcoreapp3.1, etc. You can find this information from the *.csproj file):

netcoreapp3.1

Symptom

A clear and concise description of what the bug is.

When setting up StackExchange.Redis telemetry in ConfigureServices(IServiceCollection services), telemetry messages are not created for the StackExchange.Redis calls.

What did you expect to see?

When calling an API route that contains Redis logic, I expected to see StackExchange.Redis telemetry messages in the console output.

What did you see instead?

No StackExchange.Redis telemetry messages are written to the console output.
A different route using the Http instrumentation writes System.Net.HttpClient telemetry to the console, so there seems to be a bug in the StackExchange.Redis instrumentation.

Reproduce

https://github.com/matthughes404/opentelemetry-redis-testing

We will close this issue if:

The repro project you share with us is complex. We can't investigate custom projects, so don't point us to such, please.
If we can not reproduce the behavior you're reporting.

Additional Context

I first identified this problem testing out Lightstep, when I did not see the Redis traces show up in their UI. The AspNetCore traces showed up fine in Lightstep, however. To make sure that Lightstep was not the cause, I built a local-only project to reproduce the problem.

areainstrumentation documentation

Source

matthughes404

Most helpful comment

I don't think this is a bug, but maybe the documentation is unclear. In your repro case, you're getting a new connection multiplexer in your controller. The Redis instrumentation binds itself to the connection pool that you pass to it, so if you change your ConfigureServices to look like this...

public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllers();

            var connection = ConnectionMultiplexer.Connect("localhost:6379");
            services.AddSingleton<IConnectionMultiplexer>(connection);

            services.AddOpenTelemetryTracing(builder => builder
                .AddAspNetCoreInstrumentation()
                .AddHttpClientInstrumentation()
                .AddRedisInstrumentation(connection, opt => opt.FlushInterval = TimeSpan.FromSeconds(1))
                .AddConsoleExporter());
        }

And your RedisController to look like this...

public class RedisController : ControllerBase
    {
        private readonly ILogger<RedisController> _logger;
        private readonly IConnectionMultiplexer _connectionMultiplexer;

        public RedisController(ILogger<RedisController> logger, IConnectionMultiplexer multiplexer)
        {
            _logger = logger;
            _connectionMultiplexer = multiplexer;
        }

        [HttpGet]
        public IActionResult Get()
        {
            var redis = _connectionMultiplexer.GetDatabase();

            var msg = redis.StringGet("testKey01");
            _logger.LogInformation(msg);

            return Ok(msg.ToString());
        }
    }

You should see Redis spans in the Console output.

austinlparker on 1 Dec 2020

👍2

All 4 comments

public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllers();

            var connection = ConnectionMultiplexer.Connect("localhost:6379");
            services.AddSingleton<IConnectionMultiplexer>(connection);

            services.AddOpenTelemetryTracing(builder => builder
                .AddAspNetCoreInstrumentation()
                .AddHttpClientInstrumentation()
                .AddRedisInstrumentation(connection, opt => opt.FlushInterval = TimeSpan.FromSeconds(1))
                .AddConsoleExporter());
        }

And your RedisController to look like this...

public class RedisController : ControllerBase
    {
        private readonly ILogger<RedisController> _logger;
        private readonly IConnectionMultiplexer _connectionMultiplexer;

        public RedisController(ILogger<RedisController> logger, IConnectionMultiplexer multiplexer)
        {
            _logger = logger;
            _connectionMultiplexer = multiplexer;
        }

        [HttpGet]
        public IActionResult Get()
        {
            var redis = _connectionMultiplexer.GetDatabase();

            var msg = redis.StringGet("testKey01");
            _logger.LogInformation(msg);

            return Ok(msg.ToString());
        }
    }

You should see Redis spans in the Console output.

austinlparker on 1 Dec 2020

👍2

Thanks @austinlparker for helping. Agree the doc doesn't make it obvious that only the connection passed to AddRedisInstrumentation will be instrumented. I'll make a doc fix.