selector: add filters to replace depricated client/selector filters (#1785)

selector/options.go

@@ -0,0 +1,41 @@
+package selector
+
+import "github.com/micro/go-micro/v2/router"
+
+// Options used to configure a selector
+type Options struct{}
+
+// Option updates the options
+type Option func(*Options)
+
+// Filter the routes
+type Filter func([]router.Route) []router.Route
+
+// SelectOptions used to configure selection
+type SelectOptions struct {
+	Filters []Filter
+}
+
+// SelectOption updates the select options
+type SelectOption func(*SelectOptions)
+
+// WithFilter adds a filter to the options
+func WithFilter(f Filter) SelectOption {
+	return func(o *SelectOptions) {
+		o.Filters = append(o.Filters, f)
+	}
+}
+
+// NewSelectOptions parses select options
+func NewSelectOptions(opts ...SelectOption) SelectOptions {
+	var options SelectOptions
+	for _, o := range opts {
+		o(&options)
+	}
+
+	if options.Filters == nil {
+		options.Filters = make([]Filter, 0)
+	}
+
+	return options
+}