dex/vendor/google.golang.org/grpc/keepalive/keepalive.go

/*
 *
 * Copyright 2017, 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.
 *
 */

// Package keepalive defines configurable parameters for point-to-point healthcheck.
package keepalive

import (
	"time"
)

// ClientParameters is used to set keepalive parameters on the client-side.
// These configure how the client will actively probe to notice when a connection broken
// and to cause activity so intermediaries are aware the connection is still in use.
// Make sure these parameters are set in coordination with the keepalive policy on the server,
// as incompatible settings can result in closing of connection.
type ClientParameters struct {
	// After a duration of this time if the client doesn't see any activity it pings the server to see if the transport is still alive.
	Time time.Duration // The current default value is infinity.
	// After having pinged for keepalive check, the client waits for a duration of Timeout and if no activity is seen even after that
	// the connection is closed.
	Timeout time.Duration // The current default value is 20 seconds.
	// If true, client runs keepalive checks even with no active RPCs.
	PermitWithoutStream bool // false by default.
}

// ServerParameters is used to set keepalive and max-age parameters on the server-side.
type ServerParameters struct {
	// MaxConnectionIdle is a duration for the amount of time after which an idle connection would be closed by sending a GoAway.
	// Idleness duration is defined since the most recent time the number of outstanding RPCs became zero or the connection establishment.
	MaxConnectionIdle time.Duration // The current default value is infinity.
	// MaxConnectionAge is a duration for the maximum amount of time a connection may exist before it will be closed by sending a GoAway.
	// A random jitter of +/-10% will be added to MaxConnectionAge to spread out connection storms.
	MaxConnectionAge time.Duration // The current default value is infinity.
	// MaxConnectinoAgeGrace is an additive period after MaxConnectionAge after which the connection will be forcibly closed.
	MaxConnectionAgeGrace time.Duration // The current default value is infinity.
	// After a duration of this time if the server doesn't see any activity it pings the client to see if the transport is still alive.
	Time time.Duration // The current default value is 2 hours.
	// After having pinged for keepalive check, the server waits for a duration of Timeout and if no activity is seen even after that
	// the connection is closed.
	Timeout time.Duration // The current default value is 20 seconds.
}

// EnforcementPolicy is used to set keepalive enforcement policy on the server-side.
// Server will close connection with a client that violates this policy.
type EnforcementPolicy struct {
	// MinTime is the minimum amount of time a client should wait before sending a keepalive ping.
	MinTime time.Duration // The current default value is 5 minutes.
	// If true, server expects keepalive pings even when there are no active streams(RPCs).
	PermitWithoutStream bool // false by default.
}