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Beego/vendor/github.com/couchbase/gomemcached/client/upr_feed.go
2018-07-30 12:05:51 +08:00

801 lines
23 KiB
Go

// go implementation of upr client.
// See https://github.com/couchbaselabs/cbupr/blob/master/transport-spec.md
// TODO
// 1. Use a pool allocator to avoid garbage
package memcached
import (
"encoding/binary"
"errors"
"fmt"
"github.com/couchbase/gomemcached"
"github.com/couchbase/goutils/logging"
"strconv"
"sync"
)
const uprMutationExtraLen = 30
const uprDeletetionExtraLen = 18
const uprSnapshotExtraLen = 20
const bufferAckThreshold = 0.2
const opaqueOpen = 0xBEAF0001
const opaqueFailover = 0xDEADBEEF
const uprDefaultNoopInterval = 120
// UprEvent memcached events for UPR streams.
type UprEvent struct {
Opcode gomemcached.CommandCode // Type of event
Status gomemcached.Status // Response status
VBucket uint16 // VBucket this event applies to
DataType uint8 // data type
Opaque uint16 // 16 MSB of opaque
VBuuid uint64 // This field is set by downstream
Flags uint32 // Item flags
Expiry uint32 // Item expiration time
Key, Value []byte // Item key/value
OldValue []byte // TODO: TBD: old document value
Cas uint64 // CAS value of the item
Seqno uint64 // sequence number of the mutation
RevSeqno uint64 // rev sequence number : deletions
LockTime uint32 // Lock time
MetadataSize uint16 // Metadata size
SnapstartSeq uint64 // start sequence number of this snapshot
SnapendSeq uint64 // End sequence number of the snapshot
SnapshotType uint32 // 0: disk 1: memory
FailoverLog *FailoverLog // Failover log containing vvuid and sequnce number
Error error // Error value in case of a failure
ExtMeta []byte
AckSize uint32 // The number of bytes that can be Acked to DCP
}
// UprStream is per stream data structure over an UPR Connection.
type UprStream struct {
Vbucket uint16 // Vbucket id
Vbuuid uint64 // vbucket uuid
StartSeq uint64 // start sequence number
EndSeq uint64 // end sequence number
connected bool
}
// UprFeed represents an UPR feed. A feed contains a connection to a single
// host and multiple vBuckets
type UprFeed struct {
// lock for feed.vbstreams
muVbstreams sync.RWMutex
// lock for feed.closed
muClosed sync.RWMutex
C <-chan *UprEvent // Exported channel for receiving UPR events
vbstreams map[uint16]*UprStream // vb->stream mapping
closer chan bool // closer
conn *Client // connection to UPR producer
Error error // error
bytesRead uint64 // total bytes read on this connection
toAckBytes uint32 // bytes client has read
maxAckBytes uint32 // Max buffer control ack bytes
stats UprStats // Stats for upr client
transmitCh chan *gomemcached.MCRequest // transmit command channel
transmitCl chan bool // closer channel for transmit go-routine
closed bool // flag indicating whether the feed has been closed
// flag indicating whether client of upr feed will send ack to upr feed
// if flag is true, upr feed will use ack from client to determine whether/when to send ack to DCP
// if flag is false, upr feed will track how many bytes it has sent to client
// and use that to determine whether/when to send ack to DCP
ackByClient bool
}
// Exported interface - to allow for mocking
type UprFeedIface interface {
Close()
Closed() bool
CloseStream(vbno, opaqueMSB uint16) error
GetError() error
GetUprStats() *UprStats
IncrementAckBytes(bytes uint32) error
GetUprEventCh() <-chan *UprEvent
StartFeed() error
StartFeedWithConfig(datachan_len int) error
UprOpen(name string, sequence uint32, bufSize uint32) error
UprOpenWithXATTR(name string, sequence uint32, bufSize uint32) error
UprRequestStream(vbno, opaqueMSB uint16, flags uint32, vuuid, startSequence, endSequence, snapStart, snapEnd uint64) error
}
type UprStats struct {
TotalBytes uint64
TotalMutation uint64
TotalBufferAckSent uint64
TotalSnapShot uint64
}
// FailoverLog containing vvuid and sequnce number
type FailoverLog [][2]uint64
// error codes
var ErrorInvalidLog = errors.New("couchbase.errorInvalidLog")
func (flogp *FailoverLog) Latest() (vbuuid, seqno uint64, err error) {
if flogp != nil {
flog := *flogp
latest := flog[len(flog)-1]
return latest[0], latest[1], nil
}
return vbuuid, seqno, ErrorInvalidLog
}
func makeUprEvent(rq gomemcached.MCRequest, stream *UprStream) *UprEvent {
event := &UprEvent{
Opcode: rq.Opcode,
VBucket: stream.Vbucket,
VBuuid: stream.Vbuuid,
Key: rq.Key,
Value: rq.Body,
Cas: rq.Cas,
ExtMeta: rq.ExtMeta,
DataType: rq.DataType,
AckSize: uint32(rq.Size()),
}
// 16 LSBits are used by client library to encode vbucket number.
// 16 MSBits are left for application to multiplex on opaque value.
event.Opaque = appOpaque(rq.Opaque)
if len(rq.Extras) >= uprMutationExtraLen &&
event.Opcode == gomemcached.UPR_MUTATION {
event.Seqno = binary.BigEndian.Uint64(rq.Extras[:8])
event.RevSeqno = binary.BigEndian.Uint64(rq.Extras[8:16])
event.Flags = binary.BigEndian.Uint32(rq.Extras[16:20])
event.Expiry = binary.BigEndian.Uint32(rq.Extras[20:24])
event.LockTime = binary.BigEndian.Uint32(rq.Extras[24:28])
event.MetadataSize = binary.BigEndian.Uint16(rq.Extras[28:30])
} else if len(rq.Extras) >= uprDeletetionExtraLen &&
event.Opcode == gomemcached.UPR_DELETION ||
event.Opcode == gomemcached.UPR_EXPIRATION {
event.Seqno = binary.BigEndian.Uint64(rq.Extras[:8])
event.RevSeqno = binary.BigEndian.Uint64(rq.Extras[8:16])
event.MetadataSize = binary.BigEndian.Uint16(rq.Extras[16:18])
} else if len(rq.Extras) >= uprSnapshotExtraLen &&
event.Opcode == gomemcached.UPR_SNAPSHOT {
event.SnapstartSeq = binary.BigEndian.Uint64(rq.Extras[:8])
event.SnapendSeq = binary.BigEndian.Uint64(rq.Extras[8:16])
event.SnapshotType = binary.BigEndian.Uint32(rq.Extras[16:20])
}
return event
}
func (event *UprEvent) String() string {
name := gomemcached.CommandNames[event.Opcode]
if name == "" {
name = fmt.Sprintf("#%d", event.Opcode)
}
return name
}
func (feed *UprFeed) sendCommands(mc *Client) {
transmitCh := feed.transmitCh
transmitCl := feed.transmitCl
loop:
for {
select {
case command := <-transmitCh:
if err := mc.Transmit(command); err != nil {
logging.Errorf("Failed to transmit command %s. Error %s", command.Opcode.String(), err.Error())
// get feed to close and runFeed routine to exit
feed.Close()
break loop
}
case <-transmitCl:
break loop
}
}
// After sendCommands exits, write to transmitCh will block forever
// when we write to transmitCh, e.g., at CloseStream(), we need to check feed closure to have an exit route
logging.Infof("sendCommands exiting")
}
// NewUprFeed creates a new UPR Feed.
// TODO: Describe side-effects on bucket instance and its connection pool.
func (mc *Client) NewUprFeed() (*UprFeed, error) {
return mc.NewUprFeedWithConfig(false /*ackByClient*/)
}
func (mc *Client) NewUprFeedWithConfig(ackByClient bool) (*UprFeed, error) {
feed := &UprFeed{
conn: mc,
closer: make(chan bool, 1),
vbstreams: make(map[uint16]*UprStream),
transmitCh: make(chan *gomemcached.MCRequest),
transmitCl: make(chan bool),
ackByClient: ackByClient,
}
go feed.sendCommands(mc)
return feed, nil
}
func (mc *Client) NewUprFeedIface() (UprFeedIface, error) {
return mc.NewUprFeed()
}
func (mc *Client) NewUprFeedWithConfigIface(ackByClient bool) (UprFeedIface, error) {
return mc.NewUprFeedWithConfig(ackByClient)
}
func doUprOpen(mc *Client, name string, sequence uint32, enableXATTR bool) error {
rq := &gomemcached.MCRequest{
Opcode: gomemcached.UPR_OPEN,
Key: []byte(name),
Opaque: opaqueOpen,
}
rq.Extras = make([]byte, 8)
binary.BigEndian.PutUint32(rq.Extras[:4], sequence)
// opens a producer type connection
flags := gomemcached.DCP_PRODUCER
if enableXATTR {
// set DCP_OPEN_INCLUDE_XATTRS bit in flags
flags = flags | gomemcached.DCP_OPEN_INCLUDE_XATTRS
}
binary.BigEndian.PutUint32(rq.Extras[4:], flags)
if err := mc.Transmit(rq); err != nil {
return err
}
if res, err := mc.Receive(); err != nil {
return err
} else if res.Opcode != gomemcached.UPR_OPEN {
return fmt.Errorf("unexpected #opcode %v", res.Opcode)
} else if rq.Opaque != res.Opaque {
return fmt.Errorf("opaque mismatch, %v over %v", res.Opaque, res.Opaque)
} else if res.Status != gomemcached.SUCCESS {
return fmt.Errorf("error %v", res.Status)
}
return nil
}
// UprOpen to connect with a UPR producer.
// Name: name of te UPR connection
// sequence: sequence number for the connection
// bufsize: max size of the application
func (feed *UprFeed) UprOpen(name string, sequence uint32, bufSize uint32) error {
return feed.uprOpen(name, sequence, bufSize, false /*enableXATTR*/)
}
// UprOpen with XATTR enabled.
func (feed *UprFeed) UprOpenWithXATTR(name string, sequence uint32, bufSize uint32) error {
return feed.uprOpen(name, sequence, bufSize, true /*enableXATTR*/)
}
func (feed *UprFeed) uprOpen(name string, sequence uint32, bufSize uint32, enableXATTR bool) error {
mc := feed.conn
var err error
if err = doUprOpen(mc, name, sequence, enableXATTR); err != nil {
return err
}
// send a UPR control message to set the window size for the this connection
if bufSize > 0 {
rq := &gomemcached.MCRequest{
Opcode: gomemcached.UPR_CONTROL,
Key: []byte("connection_buffer_size"),
Body: []byte(strconv.Itoa(int(bufSize))),
}
err = feed.writeToTransmitCh(rq)
if err != nil {
return err
}
feed.maxAckBytes = uint32(bufferAckThreshold * float32(bufSize))
}
// enable noop and set noop interval
rq := &gomemcached.MCRequest{
Opcode: gomemcached.UPR_CONTROL,
Key: []byte("enable_noop"),
Body: []byte("true"),
}
err = feed.writeToTransmitCh(rq)
if err != nil {
return err
}
rq = &gomemcached.MCRequest{
Opcode: gomemcached.UPR_CONTROL,
Key: []byte("set_noop_interval"),
Body: []byte(strconv.Itoa(int(uprDefaultNoopInterval))),
}
err = feed.writeToTransmitCh(rq)
if err != nil {
return err
}
return nil
}
// UprGetFailoverLog for given list of vbuckets.
func (mc *Client) UprGetFailoverLog(
vb []uint16) (map[uint16]*FailoverLog, error) {
rq := &gomemcached.MCRequest{
Opcode: gomemcached.UPR_FAILOVERLOG,
Opaque: opaqueFailover,
}
if err := doUprOpen(mc, "FailoverLog", 0, false); err != nil {
return nil, fmt.Errorf("UPR_OPEN Failed %s", err.Error())
}
failoverLogs := make(map[uint16]*FailoverLog)
for _, vBucket := range vb {
rq.VBucket = vBucket
if err := mc.Transmit(rq); err != nil {
return nil, err
}
res, err := mc.Receive()
if err != nil {
return nil, fmt.Errorf("failed to receive %s", err.Error())
} else if res.Opcode != gomemcached.UPR_FAILOVERLOG || res.Status != gomemcached.SUCCESS {
return nil, fmt.Errorf("unexpected #opcode %v", res.Opcode)
}
flog, err := parseFailoverLog(res.Body)
if err != nil {
return nil, fmt.Errorf("unable to parse failover logs for vb %d", vb)
}
failoverLogs[vBucket] = flog
}
return failoverLogs, nil
}
// UprRequestStream for a single vbucket.
func (feed *UprFeed) UprRequestStream(vbno, opaqueMSB uint16, flags uint32,
vuuid, startSequence, endSequence, snapStart, snapEnd uint64) error {
rq := &gomemcached.MCRequest{
Opcode: gomemcached.UPR_STREAMREQ,
VBucket: vbno,
Opaque: composeOpaque(vbno, opaqueMSB),
}
rq.Extras = make([]byte, 48) // #Extras
binary.BigEndian.PutUint32(rq.Extras[:4], flags)
binary.BigEndian.PutUint32(rq.Extras[4:8], uint32(0))
binary.BigEndian.PutUint64(rq.Extras[8:16], startSequence)
binary.BigEndian.PutUint64(rq.Extras[16:24], endSequence)
binary.BigEndian.PutUint64(rq.Extras[24:32], vuuid)
binary.BigEndian.PutUint64(rq.Extras[32:40], snapStart)
binary.BigEndian.PutUint64(rq.Extras[40:48], snapEnd)
stream := &UprStream{
Vbucket: vbno,
Vbuuid: vuuid,
StartSeq: startSequence,
EndSeq: endSequence,
}
feed.muVbstreams.Lock()
// Any client that has ever called this method, regardless of return code,
// should expect a potential UPR_CLOSESTREAM message due to this new map entry prior to Transmit.
feed.vbstreams[vbno] = stream
feed.muVbstreams.Unlock()
if err := feed.conn.Transmit(rq); err != nil {
logging.Errorf("Error in StreamRequest %s", err.Error())
// If an error occurs during transmit, then the UPRFeed will keep the stream
// in the vbstreams map. This is to prevent nil lookup from any previously
// sent stream requests.
return err
}
return nil
}
// CloseStream for specified vbucket.
func (feed *UprFeed) CloseStream(vbno, opaqueMSB uint16) error {
err := feed.validateCloseStream(vbno)
if err != nil {
logging.Infof("CloseStream for %v has been skipped because of error %v", vbno, err)
return err
}
closeStream := &gomemcached.MCRequest{
Opcode: gomemcached.UPR_CLOSESTREAM,
VBucket: vbno,
Opaque: composeOpaque(vbno, opaqueMSB),
}
feed.writeToTransmitCh(closeStream)
return nil
}
func (feed *UprFeed) GetUprEventCh() <-chan *UprEvent {
return feed.C
}
func (feed *UprFeed) GetError() error {
return feed.Error
}
func (feed *UprFeed) validateCloseStream(vbno uint16) error {
feed.muVbstreams.RLock()
defer feed.muVbstreams.RUnlock()
if feed.vbstreams[vbno] == nil {
return fmt.Errorf("Stream for vb %d has not been requested", vbno)
}
return nil
}
func (feed *UprFeed) writeToTransmitCh(rq *gomemcached.MCRequest) error {
// write to transmitCh may block forever if sendCommands has exited
// check for feed closure to have an exit route in this case
select {
case <-feed.closer:
errMsg := fmt.Sprintf("Abort sending request to transmitCh because feed has been closed. request=%v", rq)
logging.Infof(errMsg)
return errors.New(errMsg)
case feed.transmitCh <- rq:
}
return nil
}
// StartFeed to start the upper feed.
func (feed *UprFeed) StartFeed() error {
return feed.StartFeedWithConfig(10)
}
func (feed *UprFeed) StartFeedWithConfig(datachan_len int) error {
ch := make(chan *UprEvent, datachan_len)
feed.C = ch
go feed.runFeed(ch)
return nil
}
func parseFailoverLog(body []byte) (*FailoverLog, error) {
if len(body)%16 != 0 {
err := fmt.Errorf("invalid body length %v, in failover-log", len(body))
return nil, err
}
log := make(FailoverLog, len(body)/16)
for i, j := 0, 0; i < len(body); i += 16 {
vuuid := binary.BigEndian.Uint64(body[i : i+8])
seqno := binary.BigEndian.Uint64(body[i+8 : i+16])
log[j] = [2]uint64{vuuid, seqno}
j++
}
return &log, nil
}
func handleStreamRequest(
res *gomemcached.MCResponse,
headerBuf []byte,
) (gomemcached.Status, uint64, *FailoverLog, error) {
var rollback uint64
var err error
switch {
case res.Status == gomemcached.ROLLBACK:
logging.Infof("Rollback response. body=%v, headerBuf=%v\n", res.Body, headerBuf)
rollback = binary.BigEndian.Uint64(res.Body)
logging.Infof("Rollback %v for vb %v\n", rollback, res.Opaque)
return res.Status, rollback, nil, nil
case res.Status != gomemcached.SUCCESS:
err = fmt.Errorf("unexpected status %v, for %v", res.Status, res.Opaque)
return res.Status, 0, nil, err
}
flog, err := parseFailoverLog(res.Body[:])
return res.Status, rollback, flog, err
}
// generate stream end responses for all active vb streams
func (feed *UprFeed) doStreamClose(ch chan *UprEvent) {
feed.muVbstreams.RLock()
uprEvents := make([]*UprEvent, len(feed.vbstreams))
index := 0
for vbno, stream := range feed.vbstreams {
uprEvent := &UprEvent{
VBucket: vbno,
VBuuid: stream.Vbuuid,
Opcode: gomemcached.UPR_STREAMEND,
}
uprEvents[index] = uprEvent
index++
}
// release the lock before sending uprEvents to ch, which may block
feed.muVbstreams.RUnlock()
loop:
for _, uprEvent := range uprEvents {
select {
case ch <- uprEvent:
case <-feed.closer:
logging.Infof("Feed has been closed. Aborting doStreamClose.")
break loop
}
}
}
func (feed *UprFeed) runFeed(ch chan *UprEvent) {
defer close(ch)
var headerBuf [gomemcached.HDR_LEN]byte
var pkt gomemcached.MCRequest
var event *UprEvent
mc := feed.conn.Hijack()
uprStats := &feed.stats
loop:
for {
select {
case <-feed.closer:
logging.Infof("Feed has been closed. Exiting.")
break loop
default:
sendAck := false
bytes, err := pkt.Receive(mc, headerBuf[:])
if err != nil {
logging.Errorf("Error in receive %s", err.Error())
feed.Error = err
// send all the stream close messages to the client
feed.doStreamClose(ch)
break loop
} else {
event = nil
res := &gomemcached.MCResponse{
Opcode: pkt.Opcode,
Cas: pkt.Cas,
Opaque: pkt.Opaque,
Status: gomemcached.Status(pkt.VBucket),
Extras: pkt.Extras,
Key: pkt.Key,
Body: pkt.Body,
}
vb := vbOpaque(pkt.Opaque)
uprStats.TotalBytes = uint64(bytes)
feed.muVbstreams.RLock()
stream := feed.vbstreams[vb]
feed.muVbstreams.RUnlock()
switch pkt.Opcode {
case gomemcached.UPR_STREAMREQ:
if stream == nil {
logging.Infof("Stream not found for vb %d: %#v", vb, pkt)
break loop
}
status, rb, flog, err := handleStreamRequest(res, headerBuf[:])
if status == gomemcached.ROLLBACK {
event = makeUprEvent(pkt, stream)
event.Status = status
// rollback stream
logging.Infof("UPR_STREAMREQ with rollback %d for vb %d Failed: %v", rb, vb, err)
// delete the stream from the vbmap for the feed
feed.muVbstreams.Lock()
delete(feed.vbstreams, vb)
feed.muVbstreams.Unlock()
} else if status == gomemcached.SUCCESS {
event = makeUprEvent(pkt, stream)
event.Seqno = stream.StartSeq
event.FailoverLog = flog
event.Status = status
stream.connected = true
logging.Infof("UPR_STREAMREQ for vb %d successful", vb)
} else if err != nil {
logging.Errorf("UPR_STREAMREQ for vbucket %d erro %s", vb, err.Error())
event = &UprEvent{
Opcode: gomemcached.UPR_STREAMREQ,
Status: status,
VBucket: vb,
Error: err,
}
// delete the stream
feed.muVbstreams.Lock()
delete(feed.vbstreams, vb)
feed.muVbstreams.Unlock()
}
case gomemcached.UPR_MUTATION,
gomemcached.UPR_DELETION,
gomemcached.UPR_EXPIRATION:
if stream == nil {
logging.Infof("Stream not found for vb %d: %#v", vb, pkt)
break loop
}
event = makeUprEvent(pkt, stream)
uprStats.TotalMutation++
sendAck = true
case gomemcached.UPR_STREAMEND:
if stream == nil {
logging.Infof("Stream not found for vb %d: %#v", vb, pkt)
break loop
}
//stream has ended
event = makeUprEvent(pkt, stream)
logging.Infof("Stream Ended for vb %d", vb)
sendAck = true
feed.muVbstreams.Lock()
delete(feed.vbstreams, vb)
feed.muVbstreams.Unlock()
case gomemcached.UPR_SNAPSHOT:
if stream == nil {
logging.Infof("Stream not found for vb %d: %#v", vb, pkt)
break loop
}
// snapshot marker
event = makeUprEvent(pkt, stream)
uprStats.TotalSnapShot++
sendAck = true
case gomemcached.UPR_FLUSH:
if stream == nil {
logging.Infof("Stream not found for vb %d: %#v", vb, pkt)
break loop
}
// special processing for flush ?
event = makeUprEvent(pkt, stream)
case gomemcached.UPR_CLOSESTREAM:
if stream == nil {
logging.Infof("Stream not found for vb %d: %#v", vb, pkt)
break loop
}
event = makeUprEvent(pkt, stream)
event.Opcode = gomemcached.UPR_STREAMEND // opcode re-write !!
logging.Infof("Stream Closed for vb %d StreamEnd simulated", vb)
sendAck = true
feed.muVbstreams.Lock()
delete(feed.vbstreams, vb)
feed.muVbstreams.Unlock()
case gomemcached.UPR_ADDSTREAM:
logging.Infof("Opcode %v not implemented", pkt.Opcode)
case gomemcached.UPR_CONTROL, gomemcached.UPR_BUFFERACK:
if res.Status != gomemcached.SUCCESS {
logging.Infof("Opcode %v received status %d", pkt.Opcode.String(), res.Status)
}
case gomemcached.UPR_NOOP:
// send a NOOP back
noop := &gomemcached.MCResponse{
Opcode: gomemcached.UPR_NOOP,
Opaque: pkt.Opaque,
}
if err := feed.conn.TransmitResponse(noop); err != nil {
logging.Warnf("failed to transmit command %s. Error %s", noop.Opcode.String(), err.Error())
}
default:
logging.Infof("Recived an unknown response for vbucket %d", vb)
}
}
if event != nil {
select {
case ch <- event:
case <-feed.closer:
logging.Infof("Feed has been closed. Skip sending events. Exiting.")
break loop
}
feed.muVbstreams.RLock()
l := len(feed.vbstreams)
feed.muVbstreams.RUnlock()
if event.Opcode == gomemcached.UPR_CLOSESTREAM && l == 0 {
logging.Infof("No more streams")
}
}
if !feed.ackByClient {
// if client does not ack, use the size of data sent to client to determine if ack to dcp is needed
feed.sendBufferAckIfNeeded(sendAck, uint32(bytes))
}
}
}
// make sure that feed is closed before we signal transmitCl and exit runFeed
feed.Close()
close(feed.transmitCl)
logging.Infof("runFeed exiting")
}
// Client, after setting ackByClient flag to true in NewUprFeedWithConfig() call,
// can call this API to notify gomemcached that the client has completed processing
// of a number of bytes
// This API is not thread safe. Caller should NOT have more than one go rountine calling this API
func (feed *UprFeed) IncrementAckBytes(bytes uint32) error {
if !feed.ackByClient {
return errors.New("Upr feed does not have ackByclient flag set")
}
feed.sendBufferAckIfNeeded(true, bytes)
return nil
}
// send buffer ack if enough ack bytes have been accumulated
func (feed *UprFeed) sendBufferAckIfNeeded(sendAck bool, bytes uint32) {
if sendAck {
totalBytes := feed.toAckBytes + bytes
if totalBytes > feed.maxAckBytes {
feed.toAckBytes = 0
feed.sendBufferAck(totalBytes)
} else {
feed.toAckBytes = totalBytes
}
}
}
// send buffer ack to dcp
func (feed *UprFeed) sendBufferAck(sendSize uint32) {
bufferAck := &gomemcached.MCRequest{
Opcode: gomemcached.UPR_BUFFERACK,
}
bufferAck.Extras = make([]byte, 4)
binary.BigEndian.PutUint32(bufferAck.Extras[:4], uint32(sendSize))
feed.writeToTransmitCh(bufferAck)
feed.stats.TotalBufferAckSent++
}
func (feed *UprFeed) GetUprStats() *UprStats {
return &feed.stats
}
func composeOpaque(vbno, opaqueMSB uint16) uint32 {
return (uint32(opaqueMSB) << 16) | uint32(vbno)
}
func appOpaque(opq32 uint32) uint16 {
return uint16((opq32 & 0xFFFF0000) >> 16)
}
func vbOpaque(opq32 uint32) uint16 {
return uint16(opq32 & 0xFFFF)
}
// Close this UprFeed.
func (feed *UprFeed) Close() {
feed.muClosed.Lock()
defer feed.muClosed.Unlock()
if !feed.closed {
close(feed.closer)
feed.closed = true
}
}
// check if the UprFeed has been closed
func (feed *UprFeed) Closed() bool {
feed.muClosed.RLock()
defer feed.muClosed.RUnlock()
return feed.closed
}