Traces not visible in Zipkin UI, when open tracing is used

[debashish2014]

Hi,

I have written below code, to see if the opentracing api can be used with this driver. It does not seem to work as I don't see anything in the Zipkin UI. However, the sample code shown in the Readme works perfectly fine.

Am I missing anything?

using OpenTracing;
using OpenTracing.Tag;
using Petabridge.Tracing.Zipkin;
using System;

namespace Zipkin.Test
{
    class Program
    {
        static void Main(string[] args)
        {
            var url = "http://localhost:9411";
            var tracer = new ZipkinTracer(new ZipkinTracerOptions(url, "ZipkinTest", debug: true));

            Console.WriteLine("Connected to Zipkin at {0}", url);
 
            using (IScope scope = tracer.BuildSpan("someWork").StartActive(finishSpanOnDispose: true))
            {
                try
                {
                    scope.Span.Log("some work");
                }
                catch (Exception ex)
                {
                    Tags.Error.Set(scope.Span, true);
                }
            }

            System.Threading.Thread.Sleep(TimeSpan.FromSeconds(3));
        }
    }
}

[Aaronontheweb]

We use the OpenTracing API for this heavily in https://phobos.petabridge.com - it works. Might be a configuration issue - are you still having this issue?

[bastijnv]

Having the same issue. Seems the using(){} with finish on dispose is not functioning as expected. Running the same code but using span.Start() and span.Finish() works.

[Aaronontheweb]

Dispose on the Span object itself calls Finish

Petabridge.Tracing.Zipkin/src/Petabridge.Tracing.Zipkin/Span.cs

Lines 102 to 105 in 6a7e6d5

	public void Dispose()
	{
	Finish();
	}

Maybe the issue is what's happening inside the Scope object - I don't believe we have a reproduction for that, so we can take a look.

[bastijnv]

Yes. My bad. Using statement has nothing to do with it. Indeed when using scopes via StartActive() it will no longer send traces. Another strange thing is that when I switch sample code to

var sb = _tracer.BuildSpan("no-op").WithTag("empty", true);
var span = sb.Start();
await Task.Delay(1000);
span.Finish();

on a simple GET method it will keep sending spans indefinitely cycling the same threads while it is not executing/reaching that code block multiple times. Though that seems to be a different issue (if not just my misunderstanding of what happens) and should not pollute this thread.

[IgorFedchenko]

@Aaronontheweb @bastijnv
The issue here is that ISpanBuilder.StartActive is using IScopeManager internally so keep track of active span (some details [here[(https://github.com/opentracing/opentracing-csharp#scopes-and-within-process-propagation)). You have to set ScopeManager property of ZipkinTracerOptions to have StartActive working.

Currently there is no built-in implementation of IScopeManager in Petabridge.Tracing.Zipkin, except NoopScopeManager class which always returnes NoopSpanBuilder, so basically ISpanBuilder.StartActive resolves to NoopSpan.Instance, which does nothing. That's why nothing is sent to Zipkin.

As a quick solution you might consider using AsyncLocalScopeManager implementation of IScopeManager that is built in OpenTracing package, like this:

 var tracer = new ZipkinTracer(new ZipkinTracerOptions(url, "ZipkinTest", debug: true)
{
    ScopeManager = new AsyncLocalScopeManager()
});

@Aaronontheweb This is not clear from README, but what do you think about using AsyncLocalScopeManager as a default scope manager instead of NoopScopeManager? This may help people have this StartActive method working out of the box.
If you agree, I will submit small PR for that, with reproducing spec

[Aaronontheweb]

Sounds like a good idea

…

Sent from my iPhone

On Jan 29, 2020, at 6:30 AM, Igor Fedchenko ***@***.***> wrote:  @Aaronontheweb @bastijnv The issue here is that ISpanBuilder.StartActive is using IScopeManager internally so keep track of active span (some details [here[(https://github.com/opentracing/opentracing-csharp#scopes-and-within-process-propagation)). You have to set ScopeManager property of ZipkinTracerOptions to have StartActive working. Currently there is no built-in implementation of IScopeManager in Petabridge.Tracing.Zipkin, except NoopScopeManager class which always returnes NoopSpanBuilder, so basically ISpanBuilder.StartActive resolves to NoopSpan.Instance, which does nothing. That's why nothing is sent to Zipkin. As a quick solution you might consider using AsyncLocalScopeManager implementation of IScopeManager that is built in OpenTracing package, like this: var tracer = new ZipkinTracer(new ZipkinTracerOptions(url, "ZipkinTest", debug: true) { ScopeManager = new AsyncLocalScopeManager() }); @Aaronontheweb This is not clear from README, but what do you think about using AsyncLocalScopeManager as a default scope manager instead of NoopScopeManager? This may help people have this StartActive method working out of the box. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or unsubscribe.

[Aaronontheweb]

So the reason why I never ran into this bug - Phobos sets up a scope manager by default in its configuration. This is definitely an issue on our end.