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From: Adrian Cole <adrian.f.cole@gmail.com>
Date: Tue, 7 Mar 2017 12:51:31 +0800
Message-ID: <CAHzwyDtVwg2gEnHWDXgeWMScZ00C8OHNCWAWDVkvoR__NzjN-A@mail.gmail.com>
Subject: Re: [DISCUSS] OpenTracing API implementation
To: dev@htrace.incubator.apache.org
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archived-at: Tue, 07 Mar 2017 04:51:36 -0000

> If nobody steps up to implement it before me or working on it yet, I'll try
> to get my hands into it. Unfortunately I'm not sure when I'd have spare
> time for it.

There will be some work needed in htrace as the OT interface is wider
in most places, but not precise in others. It should be easier than
zipkin, since htrace has a single span per tracer model. That said
there are some key concerns which may or may not play out well,
particularly htrace's lack of a trace ID.

For example, you'll have choices to make on how to handle nested data
structures that are sent via its "log" api. Also, if or how to map
"special" properties defined in opentracing such as "span.kind". How
to deal with the required propagation apis (for example, how to encode
and decode a trace context in binary and text form). Sadly, there's no
compatibility kit or interop tests of any kind, so figuring out if
things work will largely be up to testers.

Anyway, in case it helps, here are a couple bridge projects:

https://github.com/openzipkin/brave-opentracing
https://github.com/DealerDotCom/sleuth-opentracing

> I had two things in mind starting this discussion:
> - check that nobody is working on it yet (to avoid wasting time if someone
> is);
pretty confident you are it.

> - check that such work would be useful for someone else.
this is an important step! There's certainly work to do, and best to
not go at it without at least a user to help q/a. I'd ping their
gitter and/or use twitter to recruit others interested if I were you.

> I haven't checked with IPMC and legal but opentracing seems to be under
> Apache License v2.0 and has no externtal deps, so it should be ok as
> external dependency.
agreed, though bear in mind OT java at least is <1.0, so you'd need to
plan for how to manage version updates (since htrace is more coarse
grained at >1.0.

Good luck on your journey!