1 files changed, 75 insertions, 0 deletions
diff --git a/src/go/collectors/go.d.plugin/modules/consul/collect_net_rtt.go b/src/go/collectors/go.d.plugin/modules/consul/collect_net_rtt.go
new file mode 100644
index 000000000..1b1853719
--- /dev/null
+++ b/src/go/collectors/go.d.plugin/modules/consul/collect_net_rtt.go
@@ -0,0 +1,75 @@
+package consul
+
+import (
+	"math"
+	"time"
+
+	"github.com/netdata/netdata/go/go.d.plugin/pkg/metrics"
+)
+
+const (
+	// https://developer.hashicorp.com/consul/api-docs/coordinate#read-lan-coordinates-for-all-nodes
+	urlPathCoordinateNodes = "/v1/coordinate/nodes"
+)
+
+type nodeCoordinates struct {
+	Node  string
+	Coord struct {
+		Vec        []float64
+		Error      float64
+		Adjustment float64
+		Height     float64
+	}
+}
+
+func (c *Consul) collectNetworkRTT(mx map[string]int64) error {
+	var coords []nodeCoordinates
+
+	if err := c.doOKDecode(urlPathCoordinateNodes, &coords); err != nil {
+		return err
+	}
+
+	var thisNode nodeCoordinates
+	var ok bool
+
+	coords, thisNode, ok = removeNodeCoordinates(coords, c.cfg.Config.NodeName)
+	if !ok || len(coords) == 0 {
+		return nil
+	}
+
+	sum := metrics.NewSummary()
+	for _, v := range coords {
+		d := calcDistance(thisNode, v)
+		sum.Observe(d.Seconds())
+	}
+	sum.WriteTo(mx, "network_lan_rtt", 1e9, 1)
+
+	return nil
+}
+
+func calcDistance(a, b nodeCoordinates) time.Duration {
+	// https://developer.hashicorp.com/consul/docs/architecture/coordinates#working-with-coordinates
+	sum := 0.0
+	for i := 0; i < len(a.Coord.Vec); i++ {
+		diff := a.Coord.Vec[i] - b.Coord.Vec[i]
+		sum += diff * diff
+	}
+
+	rtt := math.Sqrt(sum) + a.Coord.Height + b.Coord.Height
+
+	adjusted := rtt + a.Coord.Adjustment + b.Coord.Adjustment
+	if adjusted > 0.0 {
+		rtt = adjusted
+	}
+
+	return time.Duration(rtt * 1e9) // nanoseconds
+}
+
+func removeNodeCoordinates(coords []nodeCoordinates, node string) ([]nodeCoordinates, nodeCoordinates, bool) {
+	for i, v := range coords {
+		if v.Node == node {
+			return append(coords[:i], coords[i+1:]...), v, true
+		}
+	}
+	return coords, nodeCoordinates{}, false
+}