Add chain ID attribute

[lameiraatt]

This OTEP proposes the addition of a chain ID attribute to spans and logs that supports data processing/analysis and can be implemented as part of an extension to the default OTel SDK.

Feedback welcome and appreciated! 😊

[linux-foundation-easycla[bot]]

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• :white_check_mark: login: lameiraatt / name: Ana Lameira (a110a8420fa9c91617b8d84330521978ff947fb6, 6502ea627eaa21d6817e6a9fd7d9bf0c1fb7ba3b, 74364d9d0ce2ba34b07c49bb2b4a7810059d7d8d)

[bputt-e]

Does this proposal help with linked spans? Let's say I have 500 traces that get 'merged' into a new trace....What would that new trace look like, would it have any 'historical' knowledge to add any chain info or would it be considered a new trace and have nothing starting out.

[joe-elliott]

fwiw, Tempo achieves similar functionality by computing the nested set model for the tree upon storage. if this were adopted by OTEL it would make calculating the nested set quite a bit easier.

the UUID passed seems to be used to track the root process instance. imo it would be better to make this separate from the concept of the hierarchy. perhaps two different attributes that could be independently controlled:

Perhaps something like: chain.hierarchy chain.root

i'm also a bit concerned about traces with extreme depth creating enormous chain ids. perhaps a configuration option for max depth recorded would be worthwhile?

[tedsuo]

@lameiraatt we are cleaning up stale OTEP PRs. If there is no further action at this time, we will close this PR in one week. Feel free to open it again when it is time to pick it back up.