Move selector to client/selector

client/selector/default.go

@@ -0,0 +1,106 @@
+package selector
+
+import (
+	"time"
+
+	"github.com/micro/go-micro/registry"
+	"github.com/micro/go-micro/registry/cache"
+)
+
+type registrySelector struct {
+	so Options
+	rc cache.Cache
+}
+
+func (c *registrySelector) newCache() cache.Cache {
+	ropts := []cache.Option{}
+	if c.so.Context != nil {
+		if t, ok := c.so.Context.Value("selector_ttl").(time.Duration); ok {
+			ropts = append(ropts, cache.WithTTL(t))
+		}
+	}
+	return cache.New(c.so.Registry, ropts...)
+}
+
+func (c *registrySelector) Init(opts ...Option) error {
+	for _, o := range opts {
+		o(&c.so)
+	}
+
+	c.rc.Stop()
+	c.rc = c.newCache()
+
+	return nil
+}
+
+func (c *registrySelector) Options() Options {
+	return c.so
+}
+
+func (c *registrySelector) Select(service string, opts ...SelectOption) (Next, error) {
+	sopts := SelectOptions{
+		Strategy: c.so.Strategy,
+	}
+
+	for _, opt := range opts {
+		opt(&sopts)
+	}
+
+	// get the service
+	// try the cache first
+	// if that fails go directly to the registry
+	services, err := c.rc.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, ErrNoneAvailable
+	}
+
+	return sopts.Strategy(services), nil
+}
+
+func (c *registrySelector) Mark(service string, node *registry.Node, err error) {
+}
+
+func (c *registrySelector) Reset(service string) {
+}
+
+// Close stops the watcher and destroys the cache
+func (c *registrySelector) Close() error {
+	c.rc.Stop()
+
+	return nil
+}
+
+func (c *registrySelector) String() string {
+	return "registry"
+}
+
+func NewSelector(opts ...Option) Selector {
+	sopts := Options{
+		Strategy: Random,
+	}
+
+	for _, opt := range opts {
+		opt(&sopts)
+	}
+
+	if sopts.Registry == nil {
+		sopts.Registry = registry.DefaultRegistry
+	}
+
+	s := &registrySelector{
+		so: sopts,
+	}
+	s.rc = s.newCache()
+
+	return s
+}