Move to a selector package

selector/random_selector.go

@@ -0,0 +1,89 @@
+package selector
+
+import (
+	"math/rand"
+	"time"
+
+	"github.com/micro/go-micro/registry"
+)
+
+type randomSelector struct {
+	so Options
+}
+
+func init() {
+	rand.Seed(time.Now().Unix())
+}
+
+func (r *randomSelector) Select(service string, opts ...SelectOption) (Next, error) {
+	var sopts 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, ErrNotFound
+	}
+
+	var nodes []*registry.Node
+
+	for _, service := range services {
+		for _, node := range service.Nodes {
+			nodes = append(nodes, node)
+		}
+	}
+
+	if len(nodes) == 0 {
+		return nil, ErrNotFound
+	}
+
+	return func() (*registry.Node, error) {
+		i := rand.Int()
+		j := i % len(services)
+
+		if len(services[j].Nodes) == 0 {
+			return nil, ErrNotFound
+		}
+
+		k := i % len(services[j].Nodes)
+		return services[j].Nodes[k], nil
+	}, nil
+}
+
+func (r *randomSelector) Mark(service string, node *registry.Node, err error) {
+	return
+}
+
+func (r *randomSelector) Reset(service string) {
+	return
+}
+
+func (r *randomSelector) Close() error {
+	return nil
+}
+
+func newRandomSelector(opts ...Option) Selector {
+	var sopts Options
+
+	for _, opt := range opts {
+		opt(&sopts)
+	}
+
+	if sopts.Registry == nil {
+		sopts.Registry = registry.DefaultRegistry
+	}
+
+	return &randomSelector{sopts}
+}