# Semantic conventions for SignalR server metrics **Status**: [Stable][DocumentStatus] This article defines semantic conventions for SignalR metrics emitted by .NET components and runtime. - [Metric: `signalr.server.connection.duration`](#metric-signalrserverconnectionduration) - [Metric: `signalr.server.active_connections`](#metric-signalrserveractive_connections) ## Metric: `signalr.server.connection.duration` this metric SHOULD be specified with [`ExplicitBucketBoundaries`](https://github.com/open-telemetry/opentelemetry-specification/tree/v1.43.0/specification/metrics/api.md#instrument-advisory-parameters) 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](https://opentelemetry.io/docs/specs/semconv/general/attribute-requirement-level/) | Stability | |---|---|---|---|---|---| | [`signalr.connection.status`](/docs/attributes-registry/signalr.md) | string | SignalR HTTP connection closure status. | `app_shutdown`; `timeout` | `Recommended` |  | | [`signalr.transport`](/docs/attributes-registry/signalr.md) | string | [SignalR transport type](https://github.com/dotnet/aspnetcore/blob/main/src/SignalR/docs/specs/TransportProtocols.md) | `web_sockets`; `long_polling` | `Recommended` |  | --- `signalr.connection.status` 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 | |---|---|---| | `app_shutdown` | The connection was closed because the app is shutting down. |  | | `normal_closure` | The connection was closed normally. |  | | `timeout` | The connection was closed due to a timeout. |  | --- `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 | |---|---|---| | `long_polling` | LongPolling protocol |  | | `server_sent_events` | ServerSentEvents 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] |  | **[1]:** Meter name: `Microsoft.AspNetCore.Http.Connections`; Added in: ASP.NET Core 8.0 | Attribute | Type | Description | Examples | [Requirement Level](https://opentelemetry.io/docs/specs/semconv/general/attribute-requirement-level/) | Stability | |---|---|---|---|---|---| | [`signalr.connection.status`](/docs/attributes-registry/signalr.md) | string | SignalR HTTP connection closure status. | `app_shutdown`; `timeout` | `Recommended` |  | | [`signalr.transport`](/docs/attributes-registry/signalr.md) | string | [SignalR transport type](https://github.com/dotnet/aspnetcore/blob/main/src/SignalR/docs/specs/TransportProtocols.md) | `web_sockets`; `long_polling` | `Recommended` |  | --- `signalr.connection.status` 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 | |---|---|---| | `app_shutdown` | The connection was closed because the app is shutting down. |  | | `normal_closure` | The connection was closed normally. |  | | `timeout` | The connection was closed due to a timeout. |  | --- `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 | |---|---|---| | `long_polling` | LongPolling protocol |  | | `server_sent_events` | ServerSentEvents protocol |  | | `web_sockets` | WebSockets protocol |  | [DocumentStatus]: https://opentelemetry.io/docs/specs/otel/document-status