[receiver/hostmetrics] add udp connections

receiver/hostmetricsreceiver/README.md

@@ -179,8 +179,7 @@ The following feature gates control the transition process:
 - **receiver.hostmetricsreceiver.emitMetricsWithoutDirectionAttribute**: controls if the new metrics without
   `direction` attribute are emitted by the receiver.
 - **receiver.hostmetricsreceiver.emitMetricsWithDirectionAttribute**: controls if the deprecated metrics with 
-  `direction`
-  attribute are emitted by the receiver.
+  `direction` attribute are emitted by the receiver.
 
 ##### Transition schedule:
 
@@ -242,6 +241,64 @@ receivers:
 - https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/11815
 - https://github.com/open-telemetry/opentelemetry-specification/pull/2617
 
+#### Transition from metrics with "protocol" attribute
+
+Some host metrics reported are transitioning from being reported with a `protocol` attribute to being reported with the
+protocol included in the metric name to adhere to the OpenTelemetry specification
+(https://github.com/open-telemetry/opentelemetry-specification/pull/2675):
+
+- `network` scraper metrics:
+  - `system.network.connections` will become:
+    - `system.network.tcp.connections`
+    - `system.network.udp.connections`
+
+The following feature gates control the transition process:
+
+- **receiver.hostmetricsreceiver.emitMetricsWithoutProtocolAttribute**: controls if the new metrics without
+  `protocol` attribute are emitted by the receiver.
+- **receiver.hostmetricsreceiver.emitMetricsWithProtocolAttribute**: controls if the deprecated metrics with 
+  `protocol` attribute are emitted by the receiver.
+
+##### Transition schedule:
+
+1. v0.58.0, August 2022:
+
+- The new metrics are available for network scraper, but disabled by default, they can be enabled with the feature gates.
+- The old metrics with `protocol` attribute are deprecated with a warning.
+- `receiver.hostmetricsreceiver.emitMetricsWithProtocolAttribute` is enabled by default.
+- `receiver.hostmetricsreceiver.emitMetricsWithoutProtocolAttribute` is disabled by default.
+
+2. v0.60.0, September 2022:
+
+- The new metrics are enabled by default, deprecated metrics disabled, they can be enabled with the feature gates.
+- `receiver.hostmetricsreceiver.emitMetricsWithProtocolAttribute` is disabled by default.
+- `receiver.hostmetricsreceiver.emitMetricsWithoutProtocolAttribute` is enabled by default.
+
+3. v0.62.0, October 2022:
+
+- The feature gates are removed.
+- The new metrics without `protocol` attribute are always emitted.
+- The deprecated metrics with `protocol` attribute are no longer available.
+
+##### Usage:
+
+To enable the new metrics without `protocol` attribute and disable the deprecated metrics, run OTel Collector with the 
+following arguments:
+
+```sh
+otelcol --feature-gates=-receiver.hostmetricsreceiver.emitMetricsWithProtocolAttribute,+receiver.hostmetricsreceiver.emitMetricsWithoutProtocolAttribute
+```
+
+It's also possible to emit both the deprecated and the new metrics:
+
+```sh
+otelcol --feature-gates=+receiver.hostmetricsreceiver.emitMetricsWithProtocolAttribute,+receiver.hostmetricsreceiver.emitMetricsWithoutProtocolAttribute
+```
+
+##### More information:
+
+- https://github.com/open-telemetry/opentelemetry-specification/pull/2675
+
 [beta]: https://github.com/open-telemetry/opentelemetry-collector#beta
 [contrib]: https://github.com/open-telemetry/opentelemetry-collector-releases/tree/main/distributions/otelcol-contrib
 [core]: https://github.com/open-telemetry/opentelemetry-collector-releases/tree/main/distributions/otelcol

receiver/hostmetricsreceiver/internal/scraper.go

@@ -25,6 +25,8 @@ import (
 const (
 	EmitMetricsWithDirectionAttributeFeatureGateID    = "receiver.hostmetricsreceiver.emitMetricsWithDirectionAttribute"
 	EmitMetricsWithoutDirectionAttributeFeatureGateID = "receiver.hostmetricsreceiver.emitMetricsWithoutDirectionAttribute"
+	EmitMetricsWithProtocolAttributeFeatureGateID     = "receiver.hostmetricsreceiver.emitMetricsWithProtocolAttribute"
+	EmitMetricsWithoutProtocolAttributeFeatureGateID  = "receiver.hostmetricsreceiver.emitMetricsWithoutProtocolAttribute"
 )
 
 var (
@@ -47,11 +49,32 @@ var (
 			"attribute. For more details, see: " +
 			"https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/receiver/hostmetricsreceiver/README.md#feature-gate-configurations",
 	}
+	emitMetricsWithProtocolAttributeFeatureGate = featuregate.Gate{
+		ID:      EmitMetricsWithProtocolAttributeFeatureGateID,
+		Enabled: true,
+		Description: "Some process host metrics reported are transitioning from being reported with a protocol " +
+			"attribute to being reported with the protocol included in the metric name to adhere to the " +
+			"OpenTelemetry specification. This feature gate controls emitting the old metrics with the protocol " +
+			"attribute. For more details, see: " +
+			"https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/receiver/hostmetricsreceiver/README.md#feature-gate-configurations",
+	}
+
+	emitMetricsWithoutProtocolAttributeFeatureGate = featuregate.Gate{
+		ID:      EmitMetricsWithoutProtocolAttributeFeatureGateID,
+		Enabled: false,
+		Description: "Some process host metrics reported are transitioning from being reported with a protcol " +
+			"attribute to being reported with the protocol included in the metric name to adhere to the " +
+			"OpenTelemetry specification. This feature gate controls emitting the new metrics without the protocol " +
+			"attribute. For more details, see: " +
+			"https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/receiver/hostmetricsreceiver/README.md#feature-gate-configurations",
+	}
 )
 
 func init() {
 	featuregate.GetRegistry().MustRegister(emitMetricsWithDirectionAttributeFeatureGate)
 	featuregate.GetRegistry().MustRegister(emitMetricsWithoutDirectionAttributeFeatureGate)
+	featuregate.GetRegistry().MustRegister(emitMetricsWithProtocolAttributeFeatureGate)
+	featuregate.GetRegistry().MustRegister(emitMetricsWithoutProtocolAttributeFeatureGate)
 }
 
 // ScraperFactory can create a MetricScraper.

receiver/hostmetricsreceiver/internal/scraper/networkscraper/documentation.md

@@ -23,6 +23,8 @@ These are the metrics available for this scraper.
 | **system.network.packets** | The number of packets transferred. (Deprecated) | {packets} | Sum(Int) | <ul> <li>device</li> <li>direction</li> </ul> |
 | **system.network.packets.receive** | The number of packets received. | {packets} | Sum(Int) | <ul> <li>device</li> </ul> |
 | **system.network.packets.transmit** | The number of packets transmitted. | {packets} | Sum(Int) | <ul> <li>device</li> </ul> |
+| **system.network.tcp.connections** | The number of TCP connections. | {connections} | Sum(Int) | <ul> <li>state</li> </ul> |
+| **system.network.udp.connections** | The number of UDP connections. | {connections} | Sum(Int) | <ul> </ul> |
 
 **Highlighted metrics** are emitted by default. Other metrics are optional and not emitted by default.
 Any metric can be enabled or disabled with the following scraper configuration:

receiver/hostmetricsreceiver/internal/scraper/networkscraper/metadata.yaml

@@ -150,6 +150,7 @@ metrics:
       monotonic: true
     attributes: [device]
 
+  # produced when receiver.hostmetricsreceiver.emitMetricsWithProtocolAttribute feature gate is enabled
   system.network.connections:
     enabled: true
     description: The number of connections.
@@ -160,6 +161,27 @@ metrics:
       monotonic: false
     attributes: [protocol, state]
 
+  # produced when receiver.hostmetricsreceiver.emitMetricsWithoutProtocolAttribute feature gate is enabled
+  system.network.tcp.connections:
+    enabled: true
+    description: The number of TCP connections.
+    unit: "{connections}"
+    sum:
+      value_type: int
+      aggregation: cumulative
+      monotonic: false
+    attributes: [state]
+
+  # produced when receiver.hostmetricsreceiver.emitMetricsWithoutProtocolAttribute feature gate is enabled
+  system.network.udp.connections:
+    enabled: true
+    description: The number of UDP connections.
+    unit: "{connections}"
+    sum:
+      value_type: int
+      aggregation: cumulative
+      monotonic: false
+
   system.network.conntrack.count:
     enabled: false
     description: The count of entries in conntrack table.

receiver/hostmetricsreceiver/internal/scraper/networkscraper/network_scraper.go

@@ -53,6 +53,8 @@ type scraper struct {
 	conntrack                            func() ([]net.FilterStat, error)
 	emitMetricsWithDirectionAttribute    bool
 	emitMetricsWithoutDirectionAttribute bool
+	emitMetricsWithProtocolAttribute     bool
+	emitMetricsWithoutProtocolAttribute  bool
 }
 
 // newNetworkScraper creates a set of Network related metrics
@@ -66,6 +68,8 @@ func newNetworkScraper(_ context.Context, settings component.ReceiverCreateSetti
 		conntrack:                            net.FilterCounters,
 		emitMetricsWithDirectionAttribute:    featuregate.GetRegistry().IsEnabled(internal.EmitMetricsWithDirectionAttributeFeatureGateID),
 		emitMetricsWithoutDirectionAttribute: featuregate.GetRegistry().IsEnabled(internal.EmitMetricsWithoutDirectionAttributeFeatureGateID),
+		emitMetricsWithProtocolAttribute:     featuregate.GetRegistry().IsEnabled(internal.EmitMetricsWithProtocolAttributeFeatureGateID),
+		emitMetricsWithoutProtocolAttribute:  featuregate.GetRegistry().IsEnabled(internal.EmitMetricsWithoutProtocolAttributeFeatureGateID),
 	}
 
 	var err error
@@ -202,8 +206,16 @@ func (s *scraper) recordNetworkConnectionsMetrics() error {
 	}
 
 	tcpConnectionStatusCounts := getTCPConnectionStatusCounts(connections)
+	s.recordNetworkTCPConnectionsMetric(now, tcpConnectionStatusCounts)
 
-	s.recordNetworkConnectionsMetric(now, tcpConnectionStatusCounts)
+	if s.emitMetricsWithoutProtocolAttribute {
+		connections, err = s.connections("udp")
+		if err != nil {
+			return fmt.Errorf("failed to read UDP connections: %w", err)
+		}
+
+		s.mb.RecordSystemNetworkUDPConnectionsDataPoint(now, int64(len(connections)))
+	}
 	return nil
 }
 
@@ -219,9 +231,14 @@ func getTCPConnectionStatusCounts(connections []net.ConnectionStat) map[string]i
 	return tcpStatuses
 }
 
-func (s *scraper) recordNetworkConnectionsMetric(now pcommon.Timestamp, connectionStateCounts map[string]int64) {
+func (s *scraper) recordNetworkTCPConnectionsMetric(now pcommon.Timestamp, connectionStateCounts map[string]int64) {
 	for connectionState, count := range connectionStateCounts {
-		s.mb.RecordSystemNetworkConnectionsDataPoint(now, count, metadata.AttributeProtocolTcp, connectionState)
+		if s.emitMetricsWithProtocolAttribute {
+			s.mb.RecordSystemNetworkConnectionsDataPoint(now, count, metadata.AttributeProtocolTcp, connectionState)
+		}
+		if s.emitMetricsWithoutProtocolAttribute {
+			s.mb.RecordSystemNetworkTCPConnectionsDataPoint(now, count, connectionState)
+		}
 	}
 }