1// Copyright 2015 The gRPC Authors
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15// This file defines the GRPCLB LoadBalancing protocol.
16//
17// The canonical version of this proto can be found at
18// https://github.com/grpc/grpc-proto/blob/master/grpc/lb/v1/load_balancer.proto
19syntax = "proto3";
20
21package grpc.lb.v1;
22
23import "google/protobuf/duration.proto";
24import "google/protobuf/timestamp.proto";
25
26option go_package = "google.golang.org/grpc/balancer/grpclb/grpc_lb_v1";
27option java_multiple_files = true;
28option java_outer_classname = "LoadBalancerProto";
29option java_package = "io.grpc.grpclb";
30
31service LoadBalancer {
32  // Bidirectional rpc to get a list of servers.
33  rpc BalanceLoad(stream LoadBalanceRequest) returns (stream LoadBalanceResponse);
34}
35
36message LoadBalanceRequest {
37  oneof load_balance_request_type {
38    // This message should be sent on the first request to the load balancer.
39    InitialLoadBalanceRequest initial_request = 1;
40
41    // The client stats should be periodically reported to the load balancer
42    // based on the duration defined in the InitialLoadBalanceResponse.
43    ClientStats client_stats = 2;
44  }
45}
46
47message InitialLoadBalanceRequest {
48  // The name of the load balanced service (e.g., service.googleapis.com). Its
49  // length should be less than 256 bytes.
50  // The name might include a port number. How to handle the port number is up
51  // to the balancer.
52  string name = 1;
53}
54
55// Contains the number of calls finished for a particular load balance token.
56message ClientStatsPerToken {
57  // See Server.load_balance_token.
58  string load_balance_token = 1;
59
60  // The total number of RPCs that finished associated with the token.
61  int64 num_calls = 2;
62}
63
64// Contains client level statistics that are useful to load balancing. Each
65// count except the timestamp should be reset to zero after reporting the stats.
66message ClientStats {
67  // The timestamp of generating the report.
68  google.protobuf.Timestamp timestamp = 1;
69
70  // The total number of RPCs that started.
71  int64 num_calls_started = 2;
72
73  // The total number of RPCs that finished.
74  int64 num_calls_finished = 3;
75
76  // The total number of RPCs that failed to reach a server except dropped RPCs.
77  int64 num_calls_finished_with_client_failed_to_send = 6;
78
79  // The total number of RPCs that finished and are known to have been received
80  // by a server.
81  int64 num_calls_finished_known_received = 7;
82
83  // The list of dropped calls.
84  repeated ClientStatsPerToken calls_finished_with_drop = 8;
85
86  reserved 4, 5;
87}
88
89message LoadBalanceResponse {
90  oneof load_balance_response_type {
91    // This message should be sent on the first response to the client.
92    InitialLoadBalanceResponse initial_response = 1;
93
94    // Contains the list of servers selected by the load balancer. The client
95    // should send requests to these servers in the specified order.
96    ServerList server_list = 2;
97  }
98}
99
100message InitialLoadBalanceResponse {
101  // This is an application layer redirect that indicates the client should use
102  // the specified server for load balancing. When this field is non-empty in
103  // the response, the client should open a separate connection to the
104  // load_balancer_delegate and call the BalanceLoad method. Its length should
105  // be less than 64 bytes.
106  string load_balancer_delegate = 1;
107
108  // This interval defines how often the client should send the client stats
109  // to the load balancer. Stats should only be reported when the duration is
110  // positive.
111  google.protobuf.Duration client_stats_report_interval = 2;
112}
113
114message ServerList {
115  // Contains a list of servers selected by the load balancer. The list will
116  // be updated when server resolutions change or as needed to balance load
117  // across more servers. The client should consume the server list in order
118  // unless instructed otherwise via the client_config.
119  repeated Server servers = 1;
120
121  // Was google.protobuf.Duration expiration_interval.
122  reserved 3;
123}
124
125// Contains server information. When the drop field is not true, use the other
126// fields.
127message Server {
128  // A resolved address for the server, serialized in network-byte-order. It may
129  // either be an IPv4 or IPv6 address.
130  bytes ip_address = 1;
131
132  // A resolved port number for the server.
133  int32 port = 2;
134
135  // An opaque but printable token for load reporting. The client must include
136  // the token of the picked server into the initial metadata when it starts a
137  // call to that server. The token is used by the server to verify the request
138  // and to allow the server to report load to the gRPC LB system. The token is
139  // also used in client stats for reporting dropped calls.
140  //
141  // Its length can be variable but must be less than 50 bytes.
142  string load_balance_token = 3;
143
144  // Indicates whether this particular request should be dropped by the client.
145  // If the request is dropped, there will be a corresponding entry in
146  // ClientStats.calls_finished_with_drop.
147  bool drop = 4;
148
149  reserved 5;
150}
151