/
client.go
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/
client.go
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//此源码被清华学神尹成大魔王专业翻译分析并修改
//尹成QQ77025077
//尹成微信18510341407
//尹成所在QQ群721929980
//尹成邮箱 yinc13@mails.tsinghua.edu.cn
//尹成毕业于清华大学,微软区块链领域全球最有价值专家
//https://mvp.microsoft.com/zh-cn/PublicProfile/4033620
/*
版权所有IBM公司。保留所有权利。
SPDX许可证标识符:Apache-2.0
**/
package deliverclient
import (
"context"
"errors"
"fmt"
"sync"
"sync/atomic"
"time"
"github.com/hyperledger/fabric/core/comm"
"github.com/hyperledger/fabric/core/deliverservice/blocksprovider"
"github.com/hyperledger/fabric/protos/common"
"github.com/hyperledger/fabric/protos/orderer"
"google.golang.org/grpc"
)
//broadcastSetup is a function that is called by the broadcastClient immediately after each
//成功连接到订购服务
type broadcastSetup func(blocksprovider.BlocksDeliverer) error
//RetryPolicy作为参数接收尝试失败的次数
//以及指定自第一次尝试以来经过的总时间的持续时间。
//如果需要进一步尝试,它将返回:
//-下一次尝试的持续时间,真
//否则,持续时间为零,错误
type retryPolicy func(attemptNum int, elapsedTime time.Duration) (time.Duration, bool)
//clientFactory从clientconn创建GRPC广播客户端
type clientFactory func(*grpc.ClientConn) orderer.AtomicBroadcastClient
type broadcastClient struct {
stopFlag int32
stopChan chan struct{}
createClient clientFactory
shouldRetry retryPolicy
onConnect broadcastSetup
prod comm.ConnectionProducer
mutex sync.Mutex
blocksDeliverer blocksprovider.BlocksDeliverer
conn *connection
endpoint string
}
//newbroadcastclient返回具有给定参数的广播客户端
func NewBroadcastClient(prod comm.ConnectionProducer, clFactory clientFactory, onConnect broadcastSetup, bos retryPolicy) *broadcastClient {
return &broadcastClient{prod: prod, onConnect: onConnect, shouldRetry: bos, createClient: clFactory, stopChan: make(chan struct{}, 1)}
}
//recv从订购服务接收消息
func (bc *broadcastClient) Recv() (*orderer.DeliverResponse, error) {
o, err := bc.try(func() (interface{}, error) {
if bc.shouldStop() {
return nil, errors.New("closing")
}
return bc.tryReceive()
})
if err != nil {
return nil, err
}
return o.(*orderer.DeliverResponse), nil
}
//发送向订购服务发送消息
func (bc *broadcastClient) Send(msg *common.Envelope) error {
_, err := bc.try(func() (interface{}, error) {
if bc.shouldStop() {
return nil, errors.New("closing")
}
return bc.trySend(msg)
})
return err
}
func (bc *broadcastClient) trySend(msg *common.Envelope) (interface{}, error) {
bc.mutex.Lock()
stream := bc.blocksDeliverer
bc.mutex.Unlock()
if stream == nil {
return nil, errors.New("client stream has been closed")
}
return nil, stream.Send(msg)
}
func (bc *broadcastClient) tryReceive() (*orderer.DeliverResponse, error) {
bc.mutex.Lock()
stream := bc.blocksDeliverer
bc.mutex.Unlock()
if stream == nil {
return nil, errors.New("client stream has been closed")
}
return stream.Recv()
}
func (bc *broadcastClient) try(action func() (interface{}, error)) (interface{}, error) {
attempt := 0
var totalRetryTime time.Duration
var backoffDuration time.Duration
retry := true
resetAttemptCounter := func() {
attempt = 0
totalRetryTime = 0
}
for retry && !bc.shouldStop() {
resp, err := bc.doAction(action, resetAttemptCounter)
if err != nil {
attempt++
backoffDuration, retry = bc.shouldRetry(attempt, totalRetryTime)
if !retry {
logger.Warning("Got error:", err, "at", attempt, "attempt. Ceasing to retry")
break
}
logger.Warning("Got error:", err, ", at", attempt, "attempt. Retrying in", backoffDuration)
totalRetryTime += backoffDuration
bc.sleep(backoffDuration)
continue
}
return resp, nil
}
if bc.shouldStop() {
return nil, errors.New("client is closing")
}
return nil, fmt.Errorf("attempts (%d) or elapsed time (%v) exhausted", attempt, totalRetryTime)
}
func (bc *broadcastClient) doAction(action func() (interface{}, error), actionOnNewConnection func()) (interface{}, error) {
bc.mutex.Lock()
conn := bc.conn
bc.mutex.Unlock()
if conn == nil {
err := bc.connect()
if err != nil {
return nil, err
}
actionOnNewConnection()
}
resp, err := action()
if err != nil {
bc.Disconnect(false)
return nil, err
}
return resp, nil
}
func (bc *broadcastClient) sleep(duration time.Duration) {
select {
case <-time.After(duration):
case <-bc.stopChan:
}
}
func (bc *broadcastClient) connect() error {
bc.mutex.Lock()
bc.endpoint = ""
bc.mutex.Unlock()
conn, endpoint, err := bc.prod.NewConnection()
logger.Debug("Connected to", endpoint)
if err != nil {
logger.Error("Failed obtaining connection:", err)
return err
}
ctx, cf := context.WithCancel(context.Background())
logger.Debug("Establishing gRPC stream with", endpoint, "...")
abc, err := bc.createClient(conn).Deliver(ctx)
if err != nil {
logger.Error("Connection to ", endpoint, "established but was unable to create gRPC stream:", err)
conn.Close()
cf()
return err
}
err = bc.afterConnect(conn, abc, cf, endpoint)
if err == nil {
return nil
}
logger.Warning("Failed running post-connection procedures:", err)
//如果我们到达这里,请确保连接已关闭
//在我们回来之前就取消了
bc.Disconnect(false)
return err
}
func (bc *broadcastClient) afterConnect(conn *grpc.ClientConn, abc orderer.AtomicBroadcast_DeliverClient, cf context.CancelFunc, endpoint string) error {
logger.Debug("Entering")
defer logger.Debug("Exiting")
bc.mutex.Lock()
bc.endpoint = endpoint
bc.conn = &connection{ClientConn: conn, cancel: cf}
bc.blocksDeliverer = abc
if bc.shouldStop() {
bc.mutex.Unlock()
return errors.New("closing")
}
bc.mutex.Unlock()
//如果客户机在此点关闭-在OnConnect之前,
//OnConnect对该对象的任何使用都将返回一个错误。
err := bc.onConnect(bc)
//如果客户机在OnConnect之后,但在
//the following lock- this method would return an error because
//客户端已关闭。
bc.mutex.Lock()
defer bc.mutex.Unlock()
if bc.shouldStop() {
return errors.New("closing")
}
//如果在该方法退出后立即关闭客户端,
//这是因为此方法返回了零而不是错误。
//所以-connect()也将返回nil,以及goroutine的流
//返回到doaction(),在这里调用action()-并配置
//检查客户端是否已关闭。
if err == nil {
return nil
}
logger.Error("Failed setting up broadcast:", err)
return err
}
func (bc *broadcastClient) shouldStop() bool {
return atomic.LoadInt32(&bc.stopFlag) == int32(1)
}
//关闭使客户端关闭其连接并关闭
func (bc *broadcastClient) Close() {
logger.Debug("Entering")
defer logger.Debug("Exiting")
bc.mutex.Lock()
defer bc.mutex.Unlock()
if bc.shouldStop() {
return
}
atomic.StoreInt32(&bc.stopFlag, int32(1))
bc.stopChan <- struct{}{}
if bc.conn == nil {
return
}
bc.endpoint = ""
bc.conn.Close()
}
//如果disableendpoint设置为true,则disconnect将使客户端关闭现有连接,并使当前终结点在时间间隔内不可用。
func (bc *broadcastClient) Disconnect(disableEndpoint bool) {
logger.Debug("Entering")
defer logger.Debug("Exiting")
bc.mutex.Lock()
defer bc.mutex.Unlock()
if disableEndpoint && bc.endpoint != "" {
bc.prod.DisableEndpoint(bc.endpoint)
}
bc.endpoint = ""
if bc.conn == nil {
return
}
bc.conn.Close()
bc.conn = nil
bc.blocksDeliverer = nil
}
//updateEndpoints将端点更新为新值
func (bc *broadcastClient) UpdateEndpoints(endpoints []string) {
bc.prod.UpdateEndpoints(endpoints)
}
//GetEndpoints返回对服务终结点的排序
func (bc *broadcastClient) GetEndpoints() []string {
return bc.prod.GetEndpoints()
}
type connection struct {
sync.Once
*grpc.ClientConn
cancel context.CancelFunc
}
func (c *connection) Close() error {
var err error
c.Once.Do(func() {
c.cancel()
err = c.ClientConn.Close()
})
return err
}