| /* |
| * |
| * Copyright 2021 gRPC authors. |
| * |
| * 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 xds |
| |
| import ( |
| "net" |
| |
| "google.golang.org/grpc" |
| iserver "google.golang.org/grpc/xds/internal/server" |
| ) |
| |
| // ServingModeCallback returns a grpc.ServerOption which allows users to |
| // register a callback to get notified about serving mode changes. |
| func ServingModeCallback(cb ServingModeCallbackFunc) grpc.ServerOption { |
| return &smcOption{cb: cb} |
| } |
| |
| type serverOption interface { |
| applyServerOption(*serverOptions) |
| } |
| |
| // smcOption is a server option containing a callback to be invoked when the |
| // serving mode changes. |
| type smcOption struct { |
| // Embedding the empty server option makes it safe to pass it to |
| // grpc.NewServer(). |
| grpc.EmptyServerOption |
| cb ServingModeCallbackFunc |
| } |
| |
| func (s *smcOption) applyServerOption(o *serverOptions) { |
| o.modeCallback = s.cb |
| } |
| |
| type serverOptions struct { |
| modeCallback ServingModeCallbackFunc |
| } |
| |
| // ServingMode indicates the current mode of operation of the server. |
| type ServingMode = iserver.ServingMode |
| |
| const ( |
| // ServingModeServing indicates the the server contains all required xDS |
| // configuration is serving RPCs. |
| ServingModeServing = iserver.ServingModeServing |
| // ServingModeNotServing indicates that the server is not accepting new |
| // connections. Existing connections will be closed gracefully, allowing |
| // in-progress RPCs to complete. A server enters this mode when it does not |
| // contain the required xDS configuration to serve RPCs. |
| ServingModeNotServing = iserver.ServingModeNotServing |
| ) |
| |
| // ServingModeCallbackFunc is the callback that users can register to get |
| // notified about the server's serving mode changes. The callback is invoked |
| // with the address of the listener and its new mode. |
| // |
| // Users must not perform any blocking operations in this callback. |
| type ServingModeCallbackFunc func(addr net.Addr, args ServingModeChangeArgs) |
| |
| // ServingModeChangeArgs wraps the arguments passed to the serving mode callback |
| // function. |
| type ServingModeChangeArgs struct { |
| // Mode is the new serving mode of the server listener. |
| Mode ServingMode |
| // Err is set to a non-nil error if the server has transitioned into |
| // not-serving mode. |
| Err error |
| } |