set top level attribute(s) for the entire trace

[mayurkale22]

Proposed by @bputt

Feature request:
It'd be beneficial to set a default set of attributes for the entire trace that would get applied when the spans are built in the exporters.

Let's say the receiving system interacts with an attribute X and each system that sends the trace has to send X with some value. Each system can utilize a default (configured upfront) and or specify a value for X within any span where applicable.

/cc @bogdandrutu

[bogdandrutu]

Should this be at the library level or Exporter level? I think this can be added in the exporter properties.

[basvanbeek]

I agree with @bogdandrutu that can better live in the exporter properties.

Where I expect default attributes to be of use is in the scope of specific instrumentation (ex. http transport middleware, sql middleware, etc.) where the attributes would describe things like http client version, sql driver, etc.)

[mayurkale22]

@bogdandrutu
Implementation should provide a way to set global attributes during any exporter register process and provide a way to override/skip default attributes per-span (something like skipGlobalAttributes(true):java)

[kazegusuri]

+1 for this feature
I want to populate system/runtime information into Span. I think it's not exporter specific attributes.