feat: ignore existing trace

[greut]

Using Kong as our API Gateway, we'd like to prevent external actor to pollute the traces. It's currently done using the request-transformer plugin (Kong/kong-plugin-request-transformer#32) but implies lowering the PRIORITY of this zipkin.

By setting header_type to ignore, it won't read any tracing headers from the incoming request and start a new one using the default_header_type value (or falling back to b3)

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[kikito]

Hello @greut , thank you for this PR.

Do you think you could add some tests for it? See how other options are tested in the spec/ folder.

[greut]

Do you think you could add some tests for it? See how other options are tested in the spec/ folder.

the handler is not tested so far; I can take a look into it but it requires some work.

[jcchavezs]

Not sure about this change, I would implement this as a request sampler instead which is an abstraction that always unsample traces https://github.com/openzipkin/zipkin-php/blob/master/src/Zipkin/Instrumentation/Http/Server/HttpServerTracing.php#L49. This opens he possibility to a broader abstraction for different sampling strategies based on the request. Current implementation looks like mixing different concepts. José Carlos Chávez tir. 9. feb. 2021 kl. 18:54 skrev Yoan Blanc <[email protected]>:

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Do you think you could add some tests for it? See how other options are tested in the spec/ folder. the handler is not tested so far; I can take a look into it but it requires some work. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#99 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAXOYATDBJ4NDAGZGNNYQ3DS6FZG3ANCNFSM4VYSCO6A> .

[greut]

which is an abstraction that always unsample traces

@jcchavezs Thanks, however I dont' quite understand how it works from the link you've provided. The goal is not to act on the sampling strategy but on the trace capture one. Kong being exposed to the internet, we don't want it to accept incoming traces.

https://www.w3.org/TR/trace-context/#denial-of-service

[kikito]

Thanks for this PR. I merged it with small modifications (including a test) in #125

I would implement this as a request sampler

That could be an option at the Zipkin level, but not at the Kong plugin level - that would require us to include source code as part of the plugin configuration, which is something we are not prepared to support for now. There are considerations about security and permissions to be had, and that would drag this discussion for even longer. For now, the presented feature is good enough.