Move to a selector package

selector/roundrobin/round_robin_selector.go

@@ -0,0 +1,83 @@
+package roundrobin
+
+import (
+	"sync"
+
+	"github.com/micro/go-micro/registry"
+	"github.com/micro/go-micro/selector"
+)
+
+type roundRobinSelector struct {
+	so selector.Options
+}
+
+func (r *roundRobinSelector) Select(service string, opts ...selector.SelectOption) (selector.Next, error) {
+	var sopts selector.SelectOptions
+	for _, opt := range opts {
+		opt(&sopts)
+	}
+
+	// get the service
+	services, err := r.so.Registry.GetService(service)
+	if err != nil {
+		return nil, err
+	}
+
+	// apply the filters
+	for _, filter := range sopts.Filters {
+		services = filter(services)
+	}
+
+	// if there's nothing left, return
+	if len(services) == 0 {
+		return nil, selector.ErrNotFound
+	}
+
+	var nodes []*registry.Node
+
+	for _, service := range services {
+		for _, node := range service.Nodes {
+			nodes = append(nodes, node)
+		}
+	}
+
+	if len(nodes) == 0 {
+		return nil, selector.ErrNotFound
+	}
+
+	var i int
+	var mtx sync.Mutex
+
+	return func() (*registry.Node, error) {
+		mtx.Lock()
+		defer mtx.Unlock()
+		i++
+		return nodes[i%len(nodes)], nil
+	}, nil
+}
+
+func (r *roundRobinSelector) Mark(service string, node *registry.Node, err error) {
+	return
+}
+
+func (r *roundRobinSelector) Reset(service string) {
+	return
+}
+
+func (r *roundRobinSelector) Close() error {
+	return nil
+}
+
+func NewRoundRobinSelector(opts ...selector.Option) selector.Selector {
+	var sopts selector.Options
+
+	for _, opt := range opts {
+		opt(&sopts)
+	}
+
+	if sopts.Registry == nil {
+		sopts.Registry = registry.DefaultRegistry
+	}
+
+	return &roundRobinSelector{sopts}
+}

selector/roundrobin/round_robin_selector_test.go

@@ -0,0 +1,33 @@
+package roundrobin
+
+import (
+	"testing"
+
+	"github.com/micro/go-micro/registry/mock"
+	"github.com/micro/go-micro/selector"
+)
+
+func TestRoundRobinSelector(t *testing.T) {
+	counts := map[string]int{}
+
+	rr := &roundRobinSelector{
+		so: selector.Options{
+			Registry: mock.NewRegistry(),
+		},
+	}
+
+	next, err := rr.Select("foo")
+	if err != nil {
+		t.Errorf("Unexpected error calling rr select: %v", err)
+	}
+
+	for i := 0; i < 100; i++ {
+		node, err := next()
+		if err != nil {
+			t.Errorf("Expected node err, got err: %v", err)
+		}
+		counts[node.Id]++
+	}
+
+	t.Logf("Round Robin Counts %v", counts)
+}