Rename metrics counter names

[JamesNK]

Background and Motivation

See #48309 (comment)

Proposed API

Microsoft.AspNetCore.Hosting:

• current-requests -> http-server-current-requests
• request-duration -> http-server-request-duration

Microsoft.AspNetCore.Http.Connections:

• current-connections -> http-server-current-connections
• connection-duration -> http-server-connection-duration
• current-transports -> http-server-current-transports

http-server is probably the wrong name here. Maybe connection-handler?

Microsoft.AspNetCore.Server.Kestrel:

• current-connections -> kestrel-current-connections
• connection-duration -> kestrel-connection-duration
• rejected-connections -> kestrel-rejected-connections
• queued-connections -> kestrel-queued-connections
• queued-requests -> kestrel-queued-requests
• current-upgraded-connections -> kestrel-current-upgraded-connections
• tls-handshake-duration -> kestrel-tls-handshake-duration
• current-tls-handshakes -> kestrel-current-tls-handshakes

Microsoft.AspNetCore.RateLimiting:

• current-leased-requests -> rate-limiting-current-leased-requests
• leased-request-duration -> rate-limiting-leased-request-duration
• current-queued-requests -> rate-limiting-current-queued-requests
• queued-request-duration -> rate-limiting-queued-request-duration
• lease-failed-requests -> rate-limiting-lease-failed-requests

Usage Examples

Alternative Designs

Risks

Thank you for submitting this for API review. This will be reviewed by @dotnet/aspnet-api-review at the next meeting of the ASP.NET Core API Review group. Please ensure you take a look at the API review process documentation and ensure that:

• The PR contains changes to the reference-assembly that describe the API change. Or, you have included a snippet of reference-assembly-style code that illustrates the API change.
• The PR describes the impact to users, both positive (useful new APIs) and negative (breaking changes).
• Someone is assigned to "champion" this change in the meeting, and they understand the impact and design of the change.

[halter73]

API Review Notes:

• We like the kestrel- and rate-limiting- prefixes.
  • limiting seems better than limiter because it aligns with the namespace and assembly.
• As for http-server-, we like those for the hosting metrics since it's server agnostic. We don't like it for the definitely-not-signalr ;) counters.
  • How about signalr-http-transport- or http-connection-handler-?
  • "Http Connection Handler" seems too broad. One might think that Kestrel connection handlers are counted.
  • We will have a counter called signalr-http-transport-current-transports this way.
    • Can we get rid of -current-transports and add -pending-connections or -negotiating-connections?
    • Could we not have -negotiating-connections at all and only start -current-connections until a transport starts.
      • Yes. For now. We can add it later if needed

API Approved!

Microsoft.AspNetCore.Hosting:

• current-requests -> http-server-current-requests
• request-duration -> http-server-request-duration

Microsoft.AspNetCore.Http.Connections:

• current-connections ->
• connection-duration -> signalr-http-transport-connection-duration
• current-transports -> signalr-http-transport-current-connections

Microsoft.AspNetCore.Server.Kestrel:

• current-connections -> kestrel-current-connections
• connection-duration -> kestrel-connection-duration
• rejected-connections -> kestrel-rejected-connections
• queued-connections -> kestrel-queued-connections
• queued-requests -> kestrel-queued-requests
• current-upgraded-connections -> kestrel-current-upgraded-connections
• tls-handshake-duration -> kestrel-tls-handshake-duration
• current-tls-handshakes -> kestrel-current-tls-handshakes

Microsoft.AspNetCore.RateLimiting:

• current-leased-requests -> rate-limiting-current-leased-requests
• leased-request-duration -> rate-limiting-leased-request-duration
• current-queued-requests -> rate-limiting-current-queued-requests
• queued-request-duration -> rate-limiting-queued-request-duration
• lease-failed-requests -> rate-limiting-lease-failed-requests