HTTP/JSON Encoded for OTLP

[tensorchen]

Protobuf is a relatively big dependency, which some clients are not willing to take. For example, webjs, iOS/Android (in some scenarios, the size of the installation package is limited, do not want to introduce protobuf dependencies). Plain JSON is a smaller dependency and is built in the standard libraries of many programming languages.

This OTEP will be consistent with the OTEP0099(OTLP/HTTP) specification except that the payload will use JSON instead of protobuf.

[tensorchen]

@open-telemetry/specs-approvers please review.

[tigrannajaryan]

Mostly LGTM, left a couple comments.

The protocol details are a copy of OTEP0099 with appropriate replacements to use JSON instead of ProtoBuf. I believe it is the right approach to make this full copy of the text and amend the text instead of posting just the amendments in this OTEP. The full copy is more readable.

[carlosalberto]

Hey @tensorchen

The (brand new, still undocumented) flow for OTEPS is to first create an issue in https://github.com/open-telemetry/opentelemetry-specification, discuss whether it's a breaking/polemical change, and

a) If it's a relatively straightforward change, work directly in the Specification repo to reflect the proposed changes.
b) If it is indeed deemed as change that needs an OTEP, discuss it here (as you did).

Would you mind creating an issue for this in https://github.com/open-telemetry/opentelemetry-specification so we discuss it there (and we possibly later re-take this OTEP)? Since you already wrote this proposal, you can mention it in such issue ;)

Thanks in advance!

[bogdandrutu]

@open-telemetry/specs-approvers please make sure you review this :)