Hook support for adding custom dynamic metric attributes/ dimensions

[alexa-gt]

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Is your feature request related to a problem? Please describe

I am currently looking at implementing the following but running into an issue of not being able to add custom attributes/dimension, namely peer.service to the http.server.duration/ http.server.request.duration metric.

Describe the solution you'd like to see

The ability to add custom attributes and dimensions as a hook to the http.server.duration/ http.server.request.duration metric emitted by @opentelemetry/instrumentation-http, with something of the following signature:

export interface HttpRequestCustomMetricAttributeFunction {
    (request: ClientRequest, response: ServerResponse, incomingMessage: IncomingMessage): Attributes;
}

Describe alternatives you've considered

• Stick strictly to the semconv metric
  • allows no deviation or possibility of deviation without completely ditching the autoinstrumentation library, or writing a custom middleware.
• spanmetrics connector in the OTEL connector with the selected dimension
  • this is not possible for my use case as I am unable to deploy otel-col in my architecture in the near term. It has to be an app-solution.
• this hack that embeds additional info in http.route.
  • seems very strange to build an app's routing system around a workaround

Additional context

None.