VOL-1967 move api-server to separate repository

Current with voltha-go acf0adaf2d91ae72b55192cc8a939e0485918d16

Change-Id: I000ea6be0789e20c922bd671562b58a7120892ae
diff --git a/internal/pkg/afrouter/router.go b/internal/pkg/afrouter/router.go
new file mode 100644
index 0000000..7abbceb
--- /dev/null
+++ b/internal/pkg/afrouter/router.go
@@ -0,0 +1,80 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+
+ * http://www.apache.org/licenses/LICENSE-2.0
+
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package afrouter
+
+import (
+	"errors"
+	"fmt"
+	"google.golang.org/grpc"
+)
+
+var allRouters = make(map[string]Router)
+
+// The router interface
+type Router interface {
+	Name() string
+
+	// Route() returns a backend and a connection. The connection is optional and if unspecified, then any
+	// connection on the backend may be used.
+	Route(interface{}) (*backend, *connection)
+
+	Service() string
+	IsStreaming(string) (bool, bool)
+	BackendCluster(string, string) (*cluster, error)
+	FindBackendCluster(string) *cluster
+	ReplyHandler(interface{}) error
+	GetMetaKeyVal(serverStream grpc.ServerStream) (string, string, error)
+}
+
+func newRouter(config *RouterConfig) (Router, error) {
+	r, err := newMethodRouter(config)
+	if err == nil {
+		allRouters[r.Name()] = r
+	}
+	return r, err
+}
+
+func newSubRouter(rconf *RouterConfig, config *RouteConfig) (Router, error) {
+	switch config.Type {
+	case RouteTypeRpcAffinityMessage:
+		r, err := newAffinityRouter(rconf, config)
+		if err == nil {
+			allRouters[rconf.Name+config.Name] = r
+		}
+		return r, err
+	case RouteTypeBinding:
+		r, err := newBindingRouter(rconf, config)
+		if err == nil {
+			allRouters[rconf.Name+config.Name] = r
+		}
+		return r, err
+	case RouteTypeRoundRobin:
+		r, err := newRoundRobinRouter(rconf, config)
+		if err == nil {
+			allRouters[rconf.Name+config.Name] = r
+		}
+		return r, err
+	case RouteTypeSource:
+		r, err := newSourceRouter(rconf, config)
+		if err == nil {
+			allRouters[rconf.Name+config.Name] = r
+		}
+		return r, err
+	default:
+		return nil, errors.New(fmt.Sprintf("Internal error, undefined router type: %s", config.Type))
+	}
+}