Fixes #688: Change service.instance.id serialization to string

[Annosha]

Fixes #688

This PR aims to update Serialization Logic by:

Converting service.instance.id to a string before it is sent in protobuf messages. Any occurrence of service.instance.id in \otel_resource_detector.erl being assigned an integer value was modified to convert it to a binary string format, ensuring compliance with the expected data type.

Note: As a new contributor, I encountered difficulties in running tests due to a lack of documentation regarding the testing tools in the OpenTelemetry Erlang repository. Consequently, I am relying on CI/CD tests for my initial pull request. I would greatly appreciate any guidance on setting up the testing environment.

For your reference, I am using Windows with the following Erlang version: Erlang (SMP, ASYNC_THREADS) (BEAM) emulator version 15.1.2. I am currently facing challenges in setting up Rebar3.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.15%. Comparing base (3a8cbe1) to head (c4b26ce).
⚠️ Report is 179 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #793      +/-   ##
==========================================
- Coverage   73.20%   73.15%   -0.06%     
==========================================
  Files          64       64              
  Lines        1941     1941              
==========================================
- Hits         1421     1420       -1     
- Misses        520      521       +1     

Flag	Coverage Δ
api	69.90% <ø> (ø)
elixir	17.32% <ø> (ø)
erlang	74.47% <100.00%> (-0.06%)	⬇️
exporter	73.17% <ø> (ø)
sdk	77.19% <100.00%> (-0.11%)	⬇️
zipkin	54.16% <ø> (ø)

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[tsloughter]

Sorry about the lack of docs on testing. You mention not being able to setup rebar3, can you give some more details? Running tests should just require running docker compose up followed by rebar3 ct.

[tsloughter]

Actually we have service id all wrong. I don't know when this changed but the spec for it is different from when we implemented this and so our implementation needs to change to match https://github.com/open-telemetry/semantic-conventions/blob/d9d1e21a5bbb37fe8facea323491d59342a5f810/docs/attributes-registry/service.md#service-instance-id

Would you like to continue the work? Otherwise I can hop on this right away as its a bug and major difference to the spec.

Thanks for bringing it to our attention!

[Annosha]

@tsloughter I am not highly experienced in Erlang and am focusing on beginner-friendly issues for my contributions. Please feel free to proceed with the work. I would greatly appreciate any assistance in ensuring this PR is accurate and ready for merging.

[Annosha]

@tsloughter I have set up Rebar3; a system restart was required to update the environment variables. I’ve implemented the fixes in the latest commit, but I'm encountering errors when running rebar3 ct on my machine. I’m attaching the error log—could you please review it and advise if the issues are related to the changes I made?
Uploading error-log.txt…

[tsloughter]

@Annosha hey, sorry, that link to uploaded error log doesn't work. Could you just push the changes so we can see if they pass in github CI?

[Annosha]

@tsloughter sorry about the file, here is the error log. And I have pushed changes here in this PR tho.
error-log.txt

[tsloughter]

@Annosha oh, sorry for not getting back to you! To run the full test suite you need to have a collector running. You can do that with docker compose in the project. If you run that do things pass?

I haven't gotten around to fixing up service.id to match the spec but am looking at it again now. I may accept this first to at least make it a string if it'll take me a while to implement.

Sorry again for dropping the ball, and thanks!