Add SocketExpireTime to avoid long live sockets

Author: bozaro

session.go

@@ -593,6 +593,9 @@ type DialInfo struct {
 	// before being removed and closed.
 	MaxIdleTimeMS int
 
+	// Socket expire time to avoid long live connections
+	SocketExpireTime time.Duration
+
 	// DialServer optionally specifies the dial function for establishing
 	// connections with the MongoDB servers.
 	DialServer func(addr *ServerAddr) (net.Conn, error)
@@ -613,28 +616,29 @@ func (i *DialInfo) Copy() *DialInfo {
 	}
 
 	info := &DialInfo{
-		Timeout:        i.Timeout,
-		Database:       i.Database,
-		ReplicaSetName: i.ReplicaSetName,
-		Source:         i.Source,
-		Service:        i.Service,
-		ServiceHost:    i.ServiceHost,
-		Mechanism:      i.Mechanism,
-		Credentials:    i.Credentials,
-		Username:       i.Username,
-		Password:       i.Password,
-		PoolLimit:      i.PoolLimit,
-		PoolTimeout:    i.PoolTimeout,
-		ReadTimeout:    i.ReadTimeout,
-		WriteTimeout:   i.WriteTimeout,
-		AppName:        i.AppName,
-		ReadPreference: readPreference,
-		FailFast:       i.FailFast,
-		Direct:         i.Direct,
-		MinPoolSize:    i.MinPoolSize,
-		MaxIdleTimeMS:  i.MaxIdleTimeMS,
-		DialServer:     i.DialServer,
-		Dial:           i.Dial,
+		Timeout:          i.Timeout,
+		Database:         i.Database,
+		ReplicaSetName:   i.ReplicaSetName,
+		Source:           i.Source,
+		Service:          i.Service,
+		ServiceHost:      i.ServiceHost,
+		Mechanism:        i.Mechanism,
+		Credentials:      i.Credentials,
+		Username:         i.Username,
+		Password:         i.Password,
+		PoolLimit:        i.PoolLimit,
+		PoolTimeout:      i.PoolTimeout,
+		ReadTimeout:      i.ReadTimeout,
+		WriteTimeout:     i.WriteTimeout,
+		AppName:          i.AppName,
+		ReadPreference:   readPreference,
+		FailFast:         i.FailFast,
+		Direct:           i.Direct,
+		MinPoolSize:      i.MinPoolSize,
+		MaxIdleTimeMS:    i.MaxIdleTimeMS,
+		SocketExpireTime: i.SocketExpireTime,
+		DialServer:       i.DialServer,
+		Dial:             i.Dial,
 	}
 
 	info.Addrs = make([]string, len(i.Addrs))

socket.go

@@ -29,6 +29,7 @@ package mgo
 import (
 	"errors"
 	"fmt"
+	"math/rand"
 	"net"
 	"strings"
 	"sync"
@@ -59,6 +60,7 @@ type mongoSocket struct {
 	serverInfo     *mongoServerInfo
 	closeAfterIdle bool
 	lastTimeUsed   time.Time // for time based idle socket release
+	expireTime     time.Time // for avoid long lived sockets
 	sendMeta       sync.Once
 
 	dialInfo *DialInfo
@@ -197,6 +199,12 @@ func newSocket(server *mongoServer, conn net.Conn, info *DialInfo) *mongoSocket
 		replyFuncs: make(map[uint32]replyFunc),
 		dialInfo:   info,
 	}
+	if info.SocketExpireTime > 0 {
+		expireTime := info.SocketExpireTime
+		expireTime += time.Duration(rand.Uint64() % (uint64(expireTime) / 4))
+		socket.expireTime = coarseTime.Now().Add(expireTime)
+	}
+
 	socket.gotNonce.L = &socket.Mutex
 	if err := socket.InitialAcquire(server.Info(), info); err != nil {
 		panic("newSocket: InitialAcquire returned error: " + err.Error())
@@ -286,6 +294,9 @@ func (socket *mongoSocket) Release() {
 		stats.socketsInUse(-1)
 		server := socket.server
 		closeAfterIdle := socket.closeAfterIdle
+		if !closeAfterIdle && !socket.expireTime.IsZero() && coarseTime.Now().After(socket.expireTime) {
+			closeAfterIdle = true
+		}
 		socket.Unlock()
 		socket.LogoutAll()
 		if closeAfterIdle {