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// Copyright 2016, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
syntax = "proto3";
package grpc.lb.v1;
message Duration {
// Signed seconds of the span of time. Must be from -315,576,000,000
// to +315,576,000,000 inclusive.
int64 seconds = 1;
// Signed fractions of a second at nanosecond resolution of the span
// of time. Durations less than one second are represented with a 0
// `seconds` field and a positive or negative `nanos` field. For durations
// of one second or more, a non-zero value for the `nanos` field must be
// of the same sign as the `seconds` field. Must be from -999,999,999
// to +999,999,999 inclusive.
int32 nanos = 2;
}
service LoadBalancer {
// Bidirectional rpc to get a list of servers.
rpc BalanceLoad(stream LoadBalanceRequest)
returns (stream LoadBalanceResponse);
}
message LoadBalanceRequest {
oneof load_balance_request_type {
// This message should be sent on the first request to the load balancer.
InitialLoadBalanceRequest initial_request = 1;
// The client stats should be periodically reported to the load balancer
// based on the duration defined in the InitialLoadBalanceResponse.
ClientStats client_stats = 2;
}
}
message InitialLoadBalanceRequest {
// Name of load balanced service (IE, service.grpc.gslb.google.com). Its
// length should be less than 256 bytes.
string name = 1;
}
// Contains client level statistics that are useful to load balancing. Each
// count should be reset to zero after reporting the stats.
message ClientStats {
// The total number of requests sent by the client since the last report.
int64 total_requests = 1;
// The number of client rpc errors since the last report.
int64 client_rpc_errors = 2;
// The number of dropped requests since the last report.
int64 dropped_requests = 3;
}
message LoadBalanceResponse {
oneof load_balance_response_type {
// This message should be sent on the first response to the client.
InitialLoadBalanceResponse initial_response = 1;
// Contains the list of servers selected by the load balancer. The client
// should send requests to these servers in the specified order.
ServerList server_list = 2;
}
}
message InitialLoadBalanceResponse {
// This is an application layer redirect that indicates the client should use
// the specified server for load balancing. When this field is non-empty in
// the response, the client should open a separate connection to the
// load_balancer_delegate and call the BalanceLoad method. Its length should
// be less than 64 bytes.
string load_balancer_delegate = 1;
// This interval defines how often the client should send the client stats
// to the load balancer. Stats should only be reported when the duration is
// positive.
Duration client_stats_report_interval = 2;
}
message ServerList {
// Contains a list of servers selected by the load balancer. The list will
// be updated when server resolutions change or as needed to balance load
// across more servers. The client should consume the server list in order
// unless instructed otherwise via the client_config.
repeated Server servers = 1;
// Indicates the amount of time that the client should consider this server
// list as valid. It may be considered stale after waiting this interval of
// time after receiving the list. If the interval is not positive, the
// client can assume the list is valid until the next list is received.
Duration expiration_interval = 3;
}
message Server {
// A resolved address for the server, serialized in network-byte-order. It may
// either be an IPv4 or IPv6 address.
bytes ip_address = 1;
// A resolved port number for the server.
int32 port = 2;
// An opaque but printable token given to the frontend for each pick. All
// frontend requests for that pick must include the token in its initial
// metadata. The token is used by the backend to verify the request and to
// allow the backend to report load to the gRPC LB system.
//
// Its length is variable but less than 50 bytes.
string load_balance_token = 3;
// Indicates whether this particular request should be dropped by the client
// when this server is chosen from the list.
bool drop_request = 4;
}
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