Empty Span in Java Application

[Taragos]

Hello,

I am currently trying to integrate the Auto Instrumentation Javaagent into an existing application and ran into some problems.
The application is a Karaf-based application in which a gRPC-Service runs. When I add the auto instrumentation agent, it correctly generates telemetry data and I can view it in my jaeger backend.

I now tried to access current span from within a method of the grpc Service (that method is definetly instrumented as I can see it in the Jaeger UI) but all I get is an empty span.
I did add the Opentelemetry API as a dependency and I can start my application without any error being thrown.

Javaagent Version: 1.9.1
Opentelemetry API Version: 1.9.1
io.grpc Version: 1.43

How I try to access it:

        Span span = Span.current();
        LOG.info(span.toString());

What I get:

PropagatedSpan{ImmutableSpanContext{traceId=00000000000000000000000000000000, spanId=0000000000000000, traceFlags=00, traceState=ArrayBasedTraceState{entries=[]}, remote=false, valid=false}}

Is there something obvious I am missing here?

[laurit]

A small sample app that reproduces the issue would be helpful. If you have disabled instrumentations with -Dotel.instrumentation.common.default-enabled=false or in some other way then I'd suggest you try again with all instrumentations enabled and see whether it changes anything. If creating a sample app is too much effort then I'd suggest you start by examining io.grpc.Context.current() in debugger does it have otel-context in keyValueEntries field?

[Taragos]

Replicating it would take me a bit longer, so I would only do that if there is no other way.

I did not set any flags to disable certain instrumentations, so I guess they are all activated.

Debugging the application I can definetly see the otel-context variable right before I call Span.current().
It does have a key opentelemetry-trace-span-key which is filled with a valid traceId and spanId.

The parentSpanContext is the default with an id of 0000..., but it is the first call in the chain so I guess that is normal.

Additionally when I inspect: io.opentelemetry.javaagent.shaded.io.opentelemetry.context.Context.current() I can also see the filled span.

But the io.opentelemetry.context.current()-call within the Span.current() call defaults to root() which in turn only returns { }

[laurit]

Instead of Span.current() try evaluating io.opentelemetry.context.Context.current(). The returned object should be of type AgentContextWrapper. Check whether agentContext in the returned context contains opentelemetry-trace-span-key.

[Taragos]

This command results in a ClassNotFoundException...

[Taragos]

Thanks to that Exception I found the problem.
As I was running the application in a Karaf-container, I had to prepare the opentelemetry-packages as bundles.
I accidentaly split the api and context packages into two different bundles.

After providing both packages via one bundle I can now acces the current Span.
Thank you for your help!

[xsmrcek]

@Taragos I had the same problem, after some investigation I found out, that I used different version of opentelemetry-api and agent :D
This version have to match agent:
<dependency> <groupId>io.opentelemetry</groupId> <artifactId>opentelemetry-api</artifactId> <version>0.16.0</version> </dependency> <dependency> <groupId>io.opentelemetry</groupId> <artifactId>opentelemetry-extension-annotations</artifactId> <version>0.16.0</version> </dependency>
Any change you did the same mistake? :)

[Taragos]

I have for both the same dependency: 1.9.1
(Both pulled via Maven)

[laurit]

Using an old api jar would explain this. You can verify this by evaluating Span.class.getProtectionDomain().getCodeSource(), see if it is loaded from where you'd expect it to be loaded.

[Taragos]

Executing that leaves me with a string in the format of jar://bundle://<id>, properly because of Karaf.
Taking a look at the Karaf container I can see the bundles that are loaded and the api and context bundles are both in version 1.9.1, which is the same as the one the opentelemtry-javaagent prints at the startup.