gRPC metrics record duration in nanoseconds instead of milliseconds

[Sovietaced]

Description

RPC metrics are recording float64 of nanoseconds instead of milliseconds as they are intended to.

Expected behavior

If a float is going to be used to record RPC durations (similar to what is done for HTTP durations) we should be recording milliseconds and not nanoseconds.

[Sovietaced]

I will file a pull request for this momentarily.

[ash2k]

Shouldn't all duration metrics be in seconds? I think I saw this requirement/recommendation somewhere in the spec. For histograms this would mean using custom buckets (which is now possible!) as the default ones would not be granular enough for "seconds" resolution.

[MrAlias]

Shouldn't all duration metrics be in seconds? I think I saw this requirement/recommendation somewhere in the spec. For histograms this would mean using custom buckets (which is now possible!) as the default ones would not be granular enough for "seconds" resolution.

@ash2k please open an issue to track this independently.

For what it's worth, the change from ms to s happened in later versions of the semantic conventions that we do not currently support. We should track this so we can make sure we include it when we do update.

[ash2k]

@MrAlias Opened #4590. Thank you.