Its working

Signed-off-by: Miek Gieben <miek@miek.nl>

plugin/traffic/xds/assignment.go

@@ -0,0 +1,112 @@
+package xds
+
+import (
+	"fmt"
+	"math/rand"
+	"net"
+	"sync"
+
+	xdspb "github.com/envoyproxy/go-control-plane/envoy/api/v2"
+)
+
+type assignment struct {
+	mu      sync.RWMutex
+	cla     map[string]*xdspb.ClusterLoadAssignment
+	version int // not sure what do with and if we should discard all clusters.
+}
+
+func (a assignment) SetClusterLoadAssignment(cluster string, cla *xdspb.ClusterLoadAssignment) {
+	// If cla is nil we just found a cluster, check if we already know about it, or if we need to make a new entry.
+	a.mu.Lock()
+	defer a.mu.Unlock()
+	_, ok := a.cla[cluster]
+	if !ok {
+		log.Debugf("Adding cluster %q", cluster)
+		a.cla[cluster] = cla
+		return
+	}
+	if cla == nil {
+		return
+	}
+	fmt.Printf("%+v\n", cla)
+	log.Debugf("Updating cluster %q", cluster)
+	a.cla[cluster] = cla
+
+}
+
+// ClusterLoadAssignment returns the healthy endpoints and their weight.
+func (a assignment) ClusterLoadAssignment(cluster string) *xdspb.ClusterLoadAssignment {
+	a.mu.RLock()
+	cla, ok := a.cla[cluster]
+	a.mu.RUnlock()
+	if !ok {
+		return nil
+	}
+	return cla
+}
+
+func (a assignment) Clusters() []string {
+	a.mu.RLock()
+	defer a.mu.RUnlock()
+	clusters := make([]string, len(a.cla))
+	i := 0
+	for k := range a.cla {
+		clusters[i] = k
+		i++
+	}
+	return clusters
+}
+
+// Select selects a backend from cla, using weighted random selection. It only selects
+// backends that are reporting healthy.
+func (a assignment) Select(cluster string) net.IP {
+	cla := a.ClusterLoadAssignment(cluster)
+	if cla == nil {
+		return nil
+	}
+
+	total := 0
+	i := 0
+	for _, ep := range cla.Endpoints {
+		for _, lb := range ep.GetLbEndpoints() {
+			//			if lb.GetHealthStatus() != corepb.HealthStatus_HEALTHY {
+			//				continue
+			//			}
+			total += int(lb.GetLoadBalancingWeight().GetValue())
+			i++
+		}
+	}
+	if total == 0 {
+		// all weights are 0, randomly select one of the endpoints.
+		r := rand.Intn(i)
+		i := 0
+		for _, ep := range cla.Endpoints {
+			for _, lb := range ep.GetLbEndpoints() {
+				//				if lb.GetHealthStatus() != corepb.HealthStatus_HEALTHY {
+				//					continue
+				//				}
+				if r == i {
+					return net.ParseIP(lb.GetEndpoint().GetAddress().GetSocketAddress().GetAddress())
+				}
+				i++
+			}
+		}
+		return nil
+	}
+
+	r := rand.Intn(total) + 1
+
+	for _, ep := range cla.Endpoints {
+		for _, lb := range ep.GetLbEndpoints() {
+			//			if lb.GetHealthStatus() != corepb.HealthStatus_HEALTHY {
+			//				continue
+			//			}
+			r -= int(lb.GetLoadBalancingWeight().GetValue())
+			if r <= 0 {
+				return net.ParseIP(lb.GetEndpoint().GetAddress().GetSocketAddress().GetAddress())
+			}
+		}
+	}
+
+	return nil
+}