feat: Add a virtual_node_peer_attributes and virtual_node_extra_label arguments to otelcol.connector.servicegraph

docs/sources/reference/components/otelcol/otelcol.connector.servicegraph.md

@@ -68,6 +68,8 @@ You can use the following arguments with `otelcol.connector.servicegraph`:
 | `latency_histogram_buckets`      | `list(duration)` | Buckets for latency histogram metrics.                                                   | `["2ms", "4ms", "6ms", "8ms", "10ms", "50ms", "100ms", "200ms", "400ms", "800ms", "1s", "1400ms", "2s", "5s", "10s", "15s"]` | no       |
 | `metrics_flush_interval`         | `duration`       | The interval at which metrics are flushed to downstream components.                      | `"60s"`                                                                                                                      | no       |
 | `store_expiration_loop`          | `duration`       | The time to expire old entries from the store periodically.                              | `"2s"`                                                                                                                       | no       |
+| `virtual_node_extra_label`       | `bool`           | Adds an extra `virtual_node` label with an optional value of `client` or `server`, indicating which node is the uninstrumented one.                             | `false`                                                                                                                      | no       |
+| `virtual_node_peer_attributes`   | `list(string)`   | The list of attributes used to identify virtual node peer.                               | `["peer.service", "db.name", "db.system"]`                                                                                   | no       |
 
 Service graphs work by inspecting traces and looking for spans with parent-children relationship that represent a request.
 `otelcol.connector.servicegraph` uses OpenTelemetry semantic conventions to detect a myriad of requests.
@@ -114,6 +116,19 @@ When `metrics_flush_interval` is set to `0s`, metrics will be flushed on every r
 
 The attributes in `database_name_attributes` are tried in order, selecting the first match.
 
+`virtual_node_peer_attributes` is useful when an OTel-instrumented client sends a request to a service that isn't OTel-instrumented.
+Normally, `otelcol.connector.servicegraph` can't pair the client span with the server span.
+When an edge expires, `otelcol.connector.servicegraph` checks if it has peer attributes listed in `virtual_node_peer_attributes`.
+If it finds an attribute, `otelcol.connector.servicegraph` aggregates the metrics with a virtual node.
+
+If no client span is found and `virtual_node_peer_attributes` is not an empty list,
+then the service span will be paired with a virtual node called `client="user"`.
+This is useful when a client that isn't OTel-instrumented (like a web browser) sends a request to an OTel-instrumented service.
+Without a virtual node, the client span is missing, and the server span expires without being paired.
+
+Attributes configured in the `virtual_node_peer_attributes` argument are ordered by priority, with earlier attributes having higher priority.
+An empty list disables the creation of a virtual node.
+
 [Span Kind]: https://opentelemetry.io/docs/concepts/signals/traces/#span-kind
 
 ## Blocks

internal/component/otelcol/connector/servicegraph/servicegraph.go

@@ -13,6 +13,7 @@ import (
 	"github.com/open-telemetry/opentelemetry-collector-contrib/connector/servicegraphconnector"
 	otelcomponent "go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/pipeline"
+	semconv "go.opentelemetry.io/otel/semconv/v1.25.0"
 )
 
 func init() {
@@ -50,9 +51,9 @@ type Arguments struct {
 	// StoreExpirationLoop defines how often to expire old entries from the store.
 	StoreExpirationLoop time.Duration `alloy:"store_expiration_loop,attr,optional"`
 	// VirtualNodePeerAttributes the list of attributes need to match, the higher the front, the higher the priority.
-	//TODO: Add VirtualNodePeerAttributes when it's no longer controlled by
-	// the "processor.servicegraph.virtualNode" feature gate.
-	// VirtualNodePeerAttributes []string `alloy:"virtual_node_peer_attributes,attr,optional"`
+	VirtualNodePeerAttributes []string `alloy:"virtual_node_peer_attributes,attr,optional"`
+	// VirtualNodeExtraLabel enables the `virtual_node` label to be added to the spans.
+	VirtualNodeExtraLabel bool `alloy:"virtual_node_extra_label,attr,optional"`
 
 	// MetricsFlushInterval is the interval at which metrics are flushed to the exporter.
 	// If set to 0, metrics are flushed on every received batch of traces.
@@ -115,20 +116,11 @@ func (args *Arguments) SetToDefault() {
 		Dimensions:             []string{},
 		CacheLoop:              1 * time.Minute,
 		StoreExpirationLoop:    2 * time.Second,
-		DatabaseNameAttributes: []string{"db.name"},
-		MetricsFlushInterval:   60 * time.Second,
-		//TODO: Add VirtualNodePeerAttributes when it's no longer controlled by
-		// the "processor.servicegraph.virtualNode" feature gate.
-		// VirtualNodePeerAttributes: []string{
-		// 	semconv.AttributeDBName,
-		// 	semconv.AttributeNetSockPeerAddr,
-		// 	semconv.AttributeNetPeerName,
-		// 	semconv.AttributeRPCService,
-		// 	semconv.AttributeNetSockPeerName,
-		// 	semconv.AttributeNetPeerName,
-		// 	semconv.AttributeHTTPURL,
-		// 	semconv.AttributeHTTPTarget,
-		// },
+		DatabaseNameAttributes: []string{string(semconv.DBNameKey)},
+		VirtualNodePeerAttributes: []string{
+			string(semconv.PeerServiceKey), string(semconv.DBNameKey), string(semconv.DBSystemKey),
+		},
+		MetricsFlushInterval: 60 * time.Second,
 	}
 	args.Store.SetToDefault()
 	args.DebugMetrics.SetToDefault()
@@ -170,12 +162,11 @@ func (args Arguments) Convert() (otelcomponent.Config, error) {
 		},
 		CacheLoop:                   args.CacheLoop,
 		StoreExpirationLoop:         args.StoreExpirationLoop,
+		VirtualNodePeerAttributes:   args.VirtualNodePeerAttributes,
+		VirtualNodeExtraLabel:       args.VirtualNodeExtraLabel,
 		MetricsFlushInterval:        &args.MetricsFlushInterval,
 		DatabaseNameAttributes:      args.DatabaseNameAttributes,
 		ExponentialHistogramMaxSize: args.ExponentialHistogramMaxSize,
-		//TODO: Add VirtualNodePeerAttributes when it's no longer controlled by
-		// the "processor.servicegraph.virtualNode" feature gate.
-		// VirtualNodePeerAttributes: args.VirtualNodePeerAttributes,
 	}, nil
 }
 

internal/component/otelcol/connector/servicegraph/servicegraph_test.go

@@ -50,22 +50,12 @@ func TestArguments_UnmarshalAlloy(t *testing.T) {
 					MaxItems: 1000,
 					TTL:      2 * time.Second,
 				},
-				CacheLoop:              1 * time.Minute,
-				StoreExpirationLoop:    2 * time.Second,
-				DatabaseNameAttributes: []string{"db.name"},
-				MetricsFlushInterval:   ptr(60 * time.Second),
-				//TODO: Add VirtualNodePeerAttributes when it's no longer controlled by
-				// the "processor.servicegraph.virtualNode" feature gate.
-				// VirtualNodePeerAttributes: []string{
-				// 				"db.name",
-				// 				"net.sock.peer.addr",
-				// 				"net.peer.name",
-				// 				"rpc.service",
-				// 				"net.sock.peer.name",
-				// 				"net.peer.name",
-				// 				"http.url",
-				// 				"http.target",
-				// 			},
+				CacheLoop:                 1 * time.Minute,
+				StoreExpirationLoop:       2 * time.Second,
+				VirtualNodePeerAttributes: []string{"peer.service", "db.name", "db.system"},
+				VirtualNodeExtraLabel:     false,
+				DatabaseNameAttributes:    []string{"db.name"},
+				MetricsFlushInterval:      ptr(60 * time.Second),
 			},
 		},
 		{
@@ -79,6 +69,8 @@ func TestArguments_UnmarshalAlloy(t *testing.T) {
 					}
 					cache_loop = "55m"
 					store_expiration_loop = "77s"
+					virtual_node_peer_attributes = ["attr1", "attr2"]
+					virtual_node_extra_label = true
 					metrics_flush_interval = "5s"
 					exponential_histogram_max_size = 160
 					output {}
@@ -96,12 +88,11 @@ func TestArguments_UnmarshalAlloy(t *testing.T) {
 				},
 				CacheLoop:                   55 * time.Minute,
 				StoreExpirationLoop:         77 * time.Second,
+				VirtualNodePeerAttributes:   []string{"attr1", "attr2"},
+				VirtualNodeExtraLabel:       true,
 				DatabaseNameAttributes:      []string{"db.name"},
 				MetricsFlushInterval:        ptr(5 * time.Second),
 				ExponentialHistogramMaxSize: 160,
-				//TODO: Ad VirtualNodePeerAttributes when it's no longer controlled by
-				// the "processor.servicegraph.virtualNode" feature gate.
-				// VirtualNodePeerAttributes: []string{"attr1", "attr2"},
 			},
 		},
 		{

internal/converter/internal/otelcolconvert/converter_servicegraphconnector.go

@@ -61,17 +61,26 @@ func toServicegraphConnector(state *State, id componentstatus.InstanceID, cfg *s
 		metricsFlushIntervalValue = *metricsFlushInterval
 	}
 
+	// TODO: Some default values upstream are not picked up correctly - fix this.
+	// Change the upstream code to set the default values in createDefaultConfig() in factory.go.
+	// Currently, some defaults are set in newConnector() in connector.go.
+	// For example, Alloy thinks the default for virtual_node_peer_attributes should be an empty list because that's what's in factory.go.
+	// For now the servicegraph converter tests are configured to explicitly set some values so that we don't see the wrong default value.
+
 	return &servicegraph.Arguments{
 		LatencyHistogramBuckets: cfg.LatencyHistogramBuckets,
 		Dimensions:              cfg.Dimensions,
 		Store: servicegraph.StoreConfig{
 			MaxItems: cfg.Store.MaxItems,
 			TTL:      cfg.Store.TTL,
 		},
-		CacheLoop:              cfg.CacheLoop,
-		StoreExpirationLoop:    cfg.StoreExpirationLoop,
-		MetricsFlushInterval:   metricsFlushIntervalValue,
-		DatabaseNameAttributes: cfg.DatabaseNameAttributes,
+		CacheLoop:                   cfg.CacheLoop,
+		StoreExpirationLoop:         cfg.StoreExpirationLoop,
+		MetricsFlushInterval:        metricsFlushIntervalValue,
+		DatabaseNameAttributes:      cfg.DatabaseNameAttributes,
+		VirtualNodeExtraLabel:       cfg.VirtualNodeExtraLabel,
+		VirtualNodePeerAttributes:   cfg.VirtualNodePeerAttributes,
+		ExponentialHistogramMaxSize: cfg.ExponentialHistogramMaxSize,
 		Output: &otelcol.ConsumerArguments{
 			Metrics: ToTokenizedConsumers(nextMetrics),
 		},

internal/converter/internal/otelcolconvert/testdata/servicegraph.alloy

@@ -30,10 +30,11 @@ otelcol.connector.servicegraph "default" {
 		max_items = 10
 		ttl       = "1s"
 	}
-	cache_loop               = "2m0s"
-	store_expiration_loop    = "5s"
-	metrics_flush_interval   = "3m0s"
-	database_name_attributes = ["db_name3", "db_name4"]
+	cache_loop                   = "2m0s"
+	store_expiration_loop        = "5s"
+	virtual_node_peer_attributes = ["example_attribute"]
+	metrics_flush_interval       = "3m0s"
+	database_name_attributes     = ["db_name3", "db_name4"]
 
 	output {
 		metrics = [otelcol.exporter.otlp.default.input]

internal/converter/internal/otelcolconvert/testdata/servicegraph.yaml

@@ -17,6 +17,7 @@ connectors:
     store_expiration_loop: 5s
     database_name_attributes: [db_name3, db_name4]
     metrics_flush_interval: 3m
+    virtual_node_peer_attributes: [example_attribute]
 
 exporters:
   otlp: