Fix Serving Metric Queue Names + add HTTP Metrics (#6533)

* Fix Serving Metric Queue Names

* include otel http metrics

Author: dprotaso

docs/versioned/serving/observability/metrics/serving-metrics.md

@@ -13,27 +13,63 @@ Administrators can monitor Serving control plane based on the metrics exposed by
 
     These metrics may change as we flush out our migration from OpenCensus to OpenTelemetry
 
-## Queue Proxy
+## Workload Metrics
 
-The queue proxy is the per-pod sidecar that enforces container concurrency and provides metrics to the autoscaler. The following metrics provide you insights into queued
+Each workload pod has a sidecar that enforces container concurrency and provides metrics to the autoscaler. The following OTel metrics provide you insights into queued
 requests and user-container behavior.
 
-###  `kn.queueproxy.depth`
+The following attributes are included with workload metrics
+
+Name | Type | Description
+-|-|-
+`container.name` | string | Name of the container emit metrics. This is hardcoded to `queue-proxy`.
+`k8s.namespace.name` | string | Namespace of the workload
+`k8s.pod.name` | string | Name of the workload pod
+`service.version` | string | Version of the sidecar emitting metrics
+`service.name` | string | Either the name of the Knative Service, Configuration or Revision.
+`service.instance.id` | string | Identifier of the instance which is the same as the `k8s.pod.name`
+`kn.service.name` | string | Knative Service name associated with this Revision
+`kn.configuration.name` | string | Knative Configuration name associated with this Revision
+`kn.revision.name` | string | The name of the Revision
+
+###  `kn.serving.queue.depth`
 
 **Instrument Type:** Int64Gauge
 
 **Unit ([UCUM](https://ucum.org)):** {request}
 
 **Description:** Number of current items in the queue proxy queue
 
-### `kn.queueproxy.app.duration`
+### `kn.serving.invocation.duration`
 
 **Instrument Type:** Float64Histogram
 
 **Unit ([UCUM](https://ucum.org)):** s
 
 **Description:** The duration of the task execution
 
+The following attributes are included with the metric
+
+Name | Type | Description
+-|-|-
+`http.response.status_code` | int | Status code of the duration
+
+### HTTP metrics
+
+Since the sidecar receives and forwards requests to the user container it has both HTTP server and client metrics.
+
+#### HTTP Server Metrics
+
+Knative implements the [semantic conventions for HTTP Servers](https://opentelemetry.io/docs/specs/semconv/http/http-metrics/#http-server) using the OpenTelemetry [otel-go/otelhttp](https://pkg.go.dev/go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp) package.
+
+Please refer to the [OpenTelemetry docs](https://pkg.go.dev/go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp) for details about the HTTP Server metrics it exports.
+
+#### HTTP Client Metrics
+
+Knative implements the [semantic conventions for HTTP Clients](https://opentelemetry.io/docs/specs/semconv/http/http-metrics/#http-client) using the OpenTelemetry [otel-go/otelhttp](https://pkg.go.dev/go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp) package.
+
+Please refer to the [OpenTelemetry docs](https://pkg.go.dev/go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp) for details about the HTTP Client metrics it exports.
+
 ## Activator
 
 The following metrics can help you to understand how an application responds when traffic passes through the activator. For example, when scaling from zero, high request latency might mean that requests are taking too much time to be fulfilled.
@@ -51,10 +87,35 @@ The following attributes are included with the metric
 
 Name | Type | Description
 -|-|-
-`k8s.namespace.name` | string | Namespace of the Revision
+`k8s.namespace.name` | string | Namespace of the resource
+`kn.service.name` | string | Knative Service name associated with this Revision
+`kn.configuration.name` | string | Knative Configuration name associated with this Revision
+`kn.revision.name` | string | The name of the Revision
+
+### HTTP metrics
+
+Since the activator receives and forwards requests to the user workload it has both HTTP server and client metrics.
+
+#### HTTP Server Metrics
+
+Knative implements the [semantic conventions for HTTP Servers](https://opentelemetry.io/docs/specs/semconv/http/http-metrics/#http-server) using the OpenTelemetry [otel-go/otelhttp](https://pkg.go.dev/go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp) package.
+
+Please refer to the [OpenTelemetry docs](https://pkg.go.dev/go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp) for details about the HTTP Server metrics it exports.
+
+The following attributes are included in the server metrics
+
+Name | Type | Description
+-|-|-
 `kn.service.name` | string | Knative Service name associated with this Revision
 `kn.configuration.name` | string | Knative Configuration name associated with this Revision
 `kn.revision.name` | string | The name of the Revision
+`k8s.namespace.name` | string | Namespace of the resource
+
+#### HTTP Client Metrics
+
+Knative implements the [semantic conventions for HTTP Clients](https://opentelemetry.io/docs/specs/semconv/http/http-metrics/#http-client) using the OpenTelemetry [otel-go/otelhttp](https://pkg.go.dev/go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp) package.
+
+Please refer to the [OpenTelemetry docs](https://pkg.go.dev/go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp) for details about the HTTP Client metrics it exports.
 
 ## Autoscaler