Semantic Conventions for SignalR server metrics

Status: Stable

This article defines semantic conventions for SignalR metrics emitted by .NET components and runtime.

Metric: `signalr.server.connection.duration`

this metric SHOULD be specified with ExplicitBucketBoundaries of [ 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 1, 2, 5, 10, 30, 60, 120, 300 ].

Name	Instrument Type	Unit (UCUM)	Description	Stability
`signalr.server.connection.duration`	Histogram	`s`	The duration of connections on the server. [1]

[1]: Meter name: Microsoft.AspNetCore.Http.Connections; Added in: ASP.NET Core 8.0

Attribute	Type	Description	Examples	Requirement Level	Stability
`signalr.connection.status`	string	SignalR HTTP connection closure status.	`app_shutdown`; `timeout`	`Recommended`
`signalr.transport`	string	SignalR transport type	`web_sockets`; `long_polling`	`Recommended`

signalr.connection.status MUST be one of the following:

Value	Description	Stability
`normal_closure`	The connection was closed normally.
`timeout`	The connection was closed due to a timeout.
`app_shutdown`	The connection was closed because the app is shutting down.

signalr.transport has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
`server_sent_events`	ServerSentEvents protocol
`long_polling`	LongPolling protocol
`web_sockets`	WebSockets protocol

Metric: `signalr.server.active_connections`

Name	Instrument Type	Unit (UCUM)	Description	Stability
`signalr.server.active_connections`	UpDownCounter	`{connection}`	Number of connections that are currently active on the server. [1]