Move the network resolver out (#1944)

resolver/registry/registry.go

@@ -0,0 +1,39 @@
+// Package registry resolves names using the go-micro registry
+package registry
+
+import (
+	"github.com/micro/go-micro/v3/resolver"
+	"github.com/micro/go-micro/v3/registry"
+	"github.com/micro/go-micro/v3/registry/mdns"
+)
+
+// Resolver is a registry network resolver
+type Resolver struct {
+	// Registry is the registry to use otherwise we use the defaul
+	Registry registry.Registry
+}
+
+// Resolve assumes ID is a domain name e.g micro.mu
+func (r *Resolver) Resolve(name string) ([]*resolver.Record, error) {
+	reg := r.Registry
+	if reg == nil {
+		reg = mdns.NewRegistry()
+	}
+
+	services, err := reg.GetService(name)
+	if err != nil {
+		return nil, err
+	}
+
+	var records []*resolver.Record
+
+	for _, service := range services {
+		for _, node := range service.Nodes {
+			records = append(records, &resolver.Record{
+				Address: node.Address,
+			})
+		}
+	}
+
+	return records, nil
+}