Best way to add a custom span processor on top of auto-configuration

[codeforaliving]

I would like to rename a child span after performing some logic. I understand this can be accomplished with a custom SpanProcessor. What is the preferred way to add a custom SpanProcessor while still utilizing auto-config? I have seen mixed solutions and some seem deprecated. Is using an AutoConfigurationCustomizerProvider implementation the preferred way? Does this require an extension or can it be handled in application code? I am using Spring Boot. Thanks in advance!

[mateuszrzeszutek]

Hey @codeforaliving ,
The AutoConfigurationCustomizerProvider is the preferred way of registering a custom SpanProcessor.
Are you using the javaagent? If so, you'll have to build an extension jar. If you're autoinitializing the OpenTelemetry SDK directly in your application code, then it is enough to just put your custom AutoConfigurationCustomizerProvider in the application code (also keep in mind the META-INF/services file).

[mateuszrzeszutek]

Correctly redacting/sanitizing the URL path requires some knowledge about how your application works, what kind of endpoints it calls, what pieces are the variables etc - and for that reason we're not doing this universally in the instrumentation.

[codeforaliving]

Ok, thanks for the reply. Is creating a custom SpanProcessor experimental? I would have to create a separate extension JAR correct? In terms of stability, is it better to implement a custom processor in the collector contrib library or take the custom SpanProcessor route with an extension?

[codeforaliving]

Is there a way to initialize Open Telemetry in the application using auto-config (otel yaml config, env and props) but still add a custom SpanProcessor without an extension/external JAR? I ask because we are trying to accomplish this logic in a common library that is shared by multiple services and it would be great if we didn't need to add a separate JAR.

[mateuszrzeszutek]

Ok, thanks for the reply. Is creating a custom SpanProcessor experimental? ... In terms of stability, is it better to implement a custom processor in the collector contrib library or take the custom SpanProcessor route with an extension?

The AutoConfigurationCustomizerProvider is stable, SpanProcessor has been stable for a really long time too; the extension functionality in the javaagent is also stable.
I'm not sure what kind of stability guarantees the collector makes about its custom processor, but you don't need to worry about the javaagent extension mechanism.

I would have to create a separate extension JAR correct?

Yes, that is correct.

[shadow0wolf]

can we use environment variables to set specific processors , in instrumented application ?