implement "b3 single" header format

[codefromthecrypt]

Title: implement "b3 single" header format

Description:
We should permit at least parsing the more compressed "b3" header format, if not making it possible to propagate it downstream.

ex. b3: 4bf92f3577b34da6a3ce929d0e0e4736-00f067aa0ba902b7-1

This is the same format as will be used in the w3c tracestate

Details are here: openzipkin/b3-propagation#21
Example implementation is here: https://github.com/openzipkin/brave/blob/master/brave/src/main/java/brave/propagation/B3SingleFormat.java https://github.com/openzipkin/brave/blob/master/brave/src/test/java/brave/propagation/B3SingleFormatTest.java

[zyfjeff]

Is this issue still open and no one is working? If yes then i can start this one

[htuch]

@zyfjeff I've sent you an invite to join Envoy org, I can assign the issue to you when you accept.

[zyfjeff]

@adriancole Need to make it configurable, or automatic identification using "b3 single" header format or b3, if is the automatic identification, then b3 single header and b3 which higher priority?

[codefromthecrypt]

single header wins https://github.com/openzipkin/b3-propagation/blob/master/README.md#http-encodings

…

On Thu, 27 Sep 2018, 10:11 tianqian.zyf, ***@***.***> wrote: @adriancole <https://github.com/adriancole> Need to make it configurable, or automatic identification using "b3 single" header format or b3, if is the automatic identification, then b3 single header and b3 which higher priority? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#4289 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAD612dJZ8iiaunKJAHeVRllnbjbG1vbks5ufNx_gaJpZM4WQ9R-> .

[zyfjeff]

@htuch please assign to me, i will take some time to implement the recently