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
+}

plugin/traffic/xds/client.go

@@ -22,7 +22,7 @@ package xds
 
 import (
 	"context"
-	"sync"
+	"net"
 	"time"
 
 	clog "github.com/coredns/coredns/plugin/pkg/log"
@@ -34,7 +34,7 @@ import (
 	"google.golang.org/grpc"
 )
 
-var log = clog.NewWithPlugin("traffic xds:")
+var log = clog.NewWithPlugin("traffic: xds")
 
 const (
 	cdsURL = "type.googleapis.com/envoy.api.v2.Cluster"
@@ -52,45 +52,6 @@ type Client struct {
 	stop        chan struct{}
 }
 
-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 {
-		a.cla[cluster] = cla
-		return
-	}
-	if cla == nil {
-		return
-	}
-	a.cla[cluster] = cla
-
-}
-
-func (a assignment) ClusterLoadAssignment(cluster string) *xdspb.ClusterLoadAssignment {
-	return nil
-}
-
-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
-}
-
 // New returns a new client that's dialed to addr using node as the local identifier.
 func New(addr, node string) (*Client, error) {
 	// todo credentials
@@ -144,7 +105,7 @@ func (c *Client) Receive(stream adsStream) error {
 		resp, err := stream.Recv()
 		if err != nil {
 			log.Warningf("Trouble receiving from the gRPC connection: %s", err)
-			time.Sleep(1 * time.Second) // better.
+			time.Sleep(10 * time.Second) // better.
 		}
 
 		switch resp.GetTypeUrl() {
@@ -160,8 +121,7 @@ func (c *Client) Receive(stream adsStream) error {
 				}
 				c.assignments.SetClusterLoadAssignment(cluster.GetName(), nil)
 			}
-			println("CDS", len(resp.GetResources()), "processed")
-			log.Debug("Cluster discovery processed with %d resources", len(resp.GetResources()))
+			log.Debugf("Cluster discovery processed with %d resources", len(resp.GetResources()))
 			// ack the CDS proto, with we we've got. (empty version would be NACK)
 			if err := c.ClusterDiscovery(stream, resp.GetVersionInfo(), resp.GetNonce(), c.assignments.Clusters()); err != nil {
 				log.Warningf("Failed to acknowledge cluster discovery: %s", err)
@@ -188,13 +148,14 @@ func (c *Client) Receive(stream adsStream) error {
 				c.assignments.SetClusterLoadAssignment(cla.GetClusterName(), cla)
 				// ack the bloody thing
 			}
-			println("EDS", len(resp.GetResources()), "processed")
-			log.Debug("Endpoint discovery processed with %d resources", len(resp.GetResources()))
+			log.Debugf("Endpoint discovery processed with %d resources", len(resp.GetResources()))
 
 		default:
 			log.Warningf("Unknown response URL for discovery: %q", resp.GetTypeUrl())
 			continue
 		}
 	}
-	return nil
 }
+
+// Select is a small wrapper. bla bla, keeps assigmens private.
+func (c *Client) Select(cluster string) net.IP { return c.assignments.Select(cluster) }