First commit in strategy rework

selector/default.go

@@ -0,0 +1,87 @@
+package selector
+
+import (
+	"math/rand"
+	"time"
+
+	"github.com/micro/go-micro/registry"
+)
+
+type defaultSelector struct {
+	so Options
+}
+
+func init() {
+	rand.Seed(time.Now().Unix())
+}
+
+func (r *defaultSelector) Init(opts ...Option) error {
+	for _, o := range opts {
+		o(&r.so)
+	}
+	return nil
+}
+
+func (r *defaultSelector) Options() Options {
+	return r.so
+}
+
+func (r *defaultSelector) Select(service string, opts ...SelectOption) (Next, error) {
+	sopts := SelectOptions{
+		Strategy: r.so.Strategy,
+	}
+
+	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
+	}
+
+	return sopts.Strategy(services), nil
+}
+
+func (r *defaultSelector) Mark(service string, node *registry.Node, err error) {
+	return
+}
+
+func (r *defaultSelector) Reset(service string) {
+	return
+}
+
+func (r *defaultSelector) Close() error {
+	return nil
+}
+
+func (r *defaultSelector) String() string {
+	return "default"
+}
+
+func newDefaultSelector(opts ...Option) Selector {
+	sopts := Options{
+		Strategy: Random,
+	}
+
+	for _, opt := range opts {
+		opt(&sopts)
+	}
+
+	if sopts.Registry == nil {
+		sopts.Registry = registry.DefaultRegistry
+	}
+
+	return &defaultSelector{sopts}
+}