* Require that names and namespaces are one global space across all semantic convention areas
We have semantic conventions for Resources, Spans and Metrics (in the future also Logs are expected).
It was not clear if the attribute names across all convention areas should be globally unique.
This commit asserts that conventions are one space, they are not independent spaces with
their own namespaces each.
We prohibit using the same Span or Resource attribute name or metric label name but give them
slightly different meanings or value sets.
Resolves: https://github.com/open-telemetry/opentelemetry-specification/issues/815
* Address PR comments
Co-authored-by: Bogdan Drutu <bogdandrutu@gmail.com>
* Extend attribute naming rules to metric labels
We earlier defined naming rules for attributes, however we do not have
similar rules for metric labels. This commit extends the exact same
set of rules to metric labels.
This was brought up in this comment https://github.com/open-telemetry/opentelemetry-specification/pull/807#discussion_r471550053
* Address PR comments
Tigran Najaryan