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client.go
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client.go
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/*
Copyright IBM Corp. All Rights Reserved.
SPDX-License-Identifier: Apache-2.0
*/
package deliverclient
import (
"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"
"golang.org/x/net/context"
"google.golang.org/grpc"
)
// broadcastSetup is a function that is called by the broadcastClient immediately after each
// successful connection to the ordering service
type broadcastSetup func(blocksprovider.BlocksDeliverer) error
// retryPolicy receives as parameters the number of times the attempt has failed
// and a duration that specifies the total elapsed time passed since the first attempt.
// If further attempts should be made, it returns:
// - a time duration after which the next attempt would be made, true
// Else, a zero duration, false
type retryPolicy func(attemptNum int, elapsedTime time.Duration) (time.Duration, bool)
// clientFactory creates a gRPC broadcast client out of a ClientConn
type clientFactory func(*grpc.ClientConn) orderer.AtomicBroadcastClient
type broadcastClient struct {
stopFlag int32
sync.Mutex
stopChan chan struct{}
createClient clientFactory
shouldRetry retryPolicy
onConnect broadcastSetup
prod comm.ConnectionProducer
blocksprovider.BlocksDeliverer
conn *connection
endpoint string
}
// NewBroadcastClient returns a broadcastClient with the given params
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 receives a message from the ordering service
func (bc *broadcastClient) Recv() (*orderer.DeliverResponse, error) {
o, err := bc.try(func() (interface{}, error) {
if bc.shouldStop() {
return nil, errors.New("closing")
}
return bc.BlocksDeliverer.Recv()
})
if err != nil {
return nil, err
}
return o.(*orderer.DeliverResponse), nil
}
// Send sends a message to the ordering service
func (bc *broadcastClient) Send(msg *common.Envelope) error {
_, err := bc.try(func() (interface{}, error) {
if bc.shouldStop() {
return nil, errors.New("closing")
}
return nil, bc.BlocksDeliverer.Send(msg)
})
return err
}
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) {
if bc.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.endpoint = ""
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()
return err
}
err = bc.afterConnect(conn, abc, cf, endpoint)
if err == nil {
return nil
}
logger.Warning("Failed running post-connection procedures:", err)
// If we reached here, lets make sure connection is closed
// and nullified before we return
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.Lock()
bc.endpoint = endpoint
bc.conn = &connection{ClientConn: conn, cancel: cf}
bc.BlocksDeliverer = abc
if bc.shouldStop() {
bc.Unlock()
return errors.New("closing")
}
bc.Unlock()
// If the client is closed at this point- before onConnect,
// any use of this object by onConnect would return an error.
err := bc.onConnect(bc)
// If the client is closed right after onConnect, but before
// the following lock- this method would return an error because
// the client has been closed.
bc.Lock()
defer bc.Unlock()
if bc.shouldStop() {
return errors.New("closing")
}
// If the client is closed right after this method exits,
// it's because this method returned nil and not an error.
// So- connect() would return nil also, and the flow of the goroutine
// is returned to doAction(), where action() is invoked - and is configured
// to check whether the client has closed or not.
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)
}
// Close makes the client close its connection and shut down
func (bc *broadcastClient) Close() {
logger.Debug("Entering")
defer logger.Debug("Exiting")
bc.Lock()
defer bc.Unlock()
if bc.shouldStop() {
return
}
atomic.StoreInt32(&bc.stopFlag, int32(1))
bc.stopChan <- struct{}{}
if bc.conn == nil {
return
}
bc.endpoint = ""
bc.conn.Close()
}
// Disconnect makes the client close the existing connection and makes current endpoint unavailable for time interval, if disableEndpoint set to true
func (bc *broadcastClient) Disconnect(disableEndpoint bool) {
logger.Debug("Entering")
defer logger.Debug("Exiting")
bc.Lock()
defer bc.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 update endpoints to new values
func (bc *broadcastClient) UpdateEndpoints(endpoints []string) {
bc.prod.UpdateEndpoints(endpoints)
}
// GetEndpoints returns ordering service endpoints
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
}