forked from couchbase/gocbcore
/
memdclient.go
389 lines (330 loc) · 9.5 KB
/
memdclient.go
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package gocbcore
import (
"encoding/binary"
"sync"
"sync/atomic"
"time"
"unsafe"
"github.com/golang/snappy"
)
func isCompressibleOp(command commandCode) bool {
switch command {
case cmdSet:
fallthrough
case cmdAdd:
fallthrough
case cmdReplace:
fallthrough
case cmdAppend:
fallthrough
case cmdPrepend:
return true
}
return false
}
type memdClient struct {
lastActivity int64
dcpAckSize int
dcpFlowRecv int
closeNotify chan bool
connId string
closed bool
parent *Agent
conn memdConn
opList memdOpMap
errorMap *kvErrorMap
features []HelloFeature
lock sync.Mutex
streamEndNotSupported bool
}
func newMemdClient(parent *Agent, conn memdConn) *memdClient {
client := memdClient{
parent: parent,
conn: conn,
closeNotify: make(chan bool),
connId: parent.clientId + "/" + formatCbUid(randomCbUid()),
}
client.run()
return &client
}
func (client *memdClient) SupportsFeature(feature HelloFeature) bool {
return checkSupportsFeature(client.features, feature)
}
func (client *memdClient) EnableDcpBufferAck(bufferAckSize int) {
client.dcpAckSize = bufferAckSize
}
func (client *memdClient) maybeSendDcpBufferAck(packet *memdPacket) {
packetLen := 24 + len(packet.Extras) + len(packet.Key) + len(packet.Value)
client.dcpFlowRecv += packetLen
if client.dcpFlowRecv < client.dcpAckSize {
return
}
ackAmt := client.dcpFlowRecv
extrasBuf := make([]byte, 4)
binary.BigEndian.PutUint32(extrasBuf, uint32(ackAmt))
err := client.conn.WritePacket(&memdPacket{
Magic: reqMagic,
Opcode: cmdDcpBufferAck,
Extras: extrasBuf,
})
if err != nil {
logWarnf("Failed to dispatch DCP buffer ack: %s", err)
}
client.dcpFlowRecv -= ackAmt
}
func (client *memdClient) SetErrorMap(errorMap *kvErrorMap) {
client.errorMap = errorMap
}
func (client *memdClient) Address() string {
return client.conn.RemoteAddr()
}
func (client *memdClient) CloseNotify() chan bool {
return client.closeNotify
}
func (client *memdClient) takeRequestOwnership(req *memdQRequest) bool {
client.lock.Lock()
defer client.lock.Unlock()
if client.closed {
logDebugf("Attempted to put dispatched op in drained opmap")
return false
}
if !atomic.CompareAndSwapPointer(&req.waitingIn, nil, unsafe.Pointer(client)) {
logDebugf("Attempted to put dispatched op in new opmap")
return false
}
if req.isCancelled() {
atomic.CompareAndSwapPointer(&req.waitingIn, unsafe.Pointer(client), nil)
return false
}
client.opList.Add(req)
return true
}
func (client *memdClient) CancelRequest(req *memdQRequest) bool {
client.lock.Lock()
defer client.lock.Unlock()
if client.closed {
logDebugf("Attempted to remove op from drained opmap")
return false
}
removed := client.opList.Remove(req)
if removed {
atomic.CompareAndSwapPointer(&req.waitingIn, unsafe.Pointer(client), nil)
}
return removed
}
func (client *memdClient) SendRequest(req *memdQRequest) error {
addSuccess := client.takeRequestOwnership(req)
if !addSuccess {
return ErrCancelled
}
packet := &req.memdPacket
if client.SupportsFeature(FeatureSnappy) {
isCompressed := (packet.Datatype & uint8(DatatypeFlagCompressed)) != 0
packetSize := len(packet.Value)
if !isCompressed && packetSize > client.parent.compressionMinSize && isCompressibleOp(packet.Opcode) {
compressedValue := snappy.Encode(nil, packet.Value)
if float64(len(compressedValue))/float64(packetSize) <= client.parent.compressionMinRatio {
newPacket := *packet
newPacket.Value = compressedValue
newPacket.Datatype = newPacket.Datatype | uint8(DatatypeFlagCompressed)
packet = &newPacket
}
}
}
logSchedf("Writing request. %s to %s OP=0x%x. Opaque=%d", client.conn.LocalAddr(), client.Address(), req.Opcode, req.Opaque)
client.parent.startNetTrace(req)
err := client.conn.WritePacket(packet)
if err != nil {
logDebugf("memdClient write failure: %v", err)
client.CancelRequest(req)
return err
}
return nil
}
func (client *memdClient) resolveRequest(resp *memdQResponse) {
opIndex := resp.Opaque
client.lock.Lock()
// Find the request that goes with this response, don't check if the client is
// closed so that we can handle orphaned responses.
req := client.opList.FindAndMaybeRemove(opIndex, resp.Status != StatusSuccess)
client.lock.Unlock()
if req == nil {
// There is no known request that goes with this response. Ignore it.
logDebugf("Received response with no corresponding request.")
if atomic.LoadUint32(&client.parent.useZombieLogger) == 1 {
client.parent.recordZombieResponse(resp, client)
}
return
}
if !req.Persistent {
atomic.CompareAndSwapPointer(&req.waitingIn, unsafe.Pointer(client), nil)
}
req.processingLock.Lock()
if !req.Persistent {
client.parent.stopNetTrace(req, resp, client)
}
isCompressed := (resp.Datatype & uint8(DatatypeFlagCompressed)) != 0
if isCompressed && !client.parent.disableDecompression {
newValue, err := snappy.Decode(nil, resp.Value)
if err != nil {
req.processingLock.Unlock()
logDebugf("Failed to decompress value from the server for key `%s`.", req.Key)
return
}
resp.Value = newValue
resp.Datatype = resp.Datatype & ^uint8(DatatypeFlagCompressed)
}
// Give the agent an opportunity to intercept the response first
var err error
if resp.Magic == resMagic {
if resp.Status != StatusSuccess {
if ok, foundErr := findMemdError(resp.Status); ok {
err = foundErr
} else {
err = newSimpleError(resp.Status)
}
}
}
if client.parent == nil {
req.processingLock.Unlock()
} else {
if !req.Persistent {
client.parent.stopCmdTrace(req)
}
req.processingLock.Unlock()
if err != ErrCancelled {
shortCircuited, routeErr := client.parent.handleOpRoutingResp(resp, req, err)
if shortCircuited {
logSchedf("Routing callback intercepted response")
return
}
err = routeErr
}
}
// Call the requests callback handler...
logSchedf("Dispatching response callback. OP=0x%x. Opaque=%d", resp.Opcode, resp.Opaque)
req.tryCallback(resp, err)
}
func (client *memdClient) run() {
dcpBufferQ := make(chan *memdQResponse, client.parent.dcpQueueSize)
dcpKillSwitch := make(chan bool)
dcpKillNotify := make(chan bool)
go func() {
for {
select {
case resp, more := <-dcpBufferQ:
if !more {
dcpKillNotify <- true
return
}
logSchedf("Resolving response OP=0x%x. Opaque=%d", resp.Opcode, resp.Opaque)
client.resolveRequest(resp)
// See below for information on why this is here.
if !resp.isInternal {
if client.dcpAckSize > 0 {
client.maybeSendDcpBufferAck(&resp.memdPacket)
}
}
case <-dcpKillSwitch:
close(dcpBufferQ)
}
}
}()
go func() {
for {
resp := &memdQResponse{
sourceAddr: client.conn.RemoteAddr(),
sourceConnId: client.connId,
}
err := client.conn.ReadPacket(&resp.memdPacket)
if err != nil {
if !client.closed {
logErrorf("memdClient read failure: %v", err)
}
break
}
atomic.StoreInt64(&client.lastActivity, time.Now().UnixNano())
// We handle DCP no-op's directly here so we can reply immediately.
if resp.memdPacket.Opcode == cmdDcpNoop {
err := client.conn.WritePacket(&memdPacket{
Magic: resMagic,
Opcode: cmdDcpNoop,
Opaque: resp.Opaque,
})
if err != nil {
logWarnf("Failed to dispatch DCP noop reply: %s", err)
}
continue
}
// This is a fix for a bug in the server DCP implementation (MB-26363). This
// bug causes the server to fail to send a stream-end notification. The server
// does however synchronously stop the stream, and thus we can assume no more
// packets will be received following the close response.
if resp.Magic == resMagic && resp.Opcode == cmdDcpCloseStream && client.streamEndNotSupported {
closeReq := client.opList.Find(resp.Opaque)
if closeReq != nil {
vbId := closeReq.Vbucket
streamReq := client.opList.FindOpenStream(vbId)
if streamReq != nil {
endExtras := make([]byte, 4)
binary.BigEndian.PutUint32(endExtras, uint32(streamEndClosed))
endResp := &memdQResponse{
memdPacket: memdPacket{
Magic: reqMagic,
Opcode: cmdDcpStreamEnd,
Vbucket: vbId,
Opaque: streamReq.Opaque,
Extras: endExtras,
},
isInternal: true,
}
dcpBufferQ <- endResp
}
}
}
switch resp.memdPacket.Opcode {
case cmdDcpDeletion:
fallthrough
case cmdDcpExpiration:
fallthrough
case cmdDcpMutation:
fallthrough
case cmdDcpSnapshotMarker:
fallthrough
case cmdDcpStreamEnd:
dcpBufferQ <- resp
continue
default:
logSchedf("Resolving response OP=0x%x. Opaque=%d", resp.Opcode, resp.Opaque)
client.resolveRequest(resp)
}
}
client.lock.Lock()
if client.closed {
client.lock.Unlock()
} else {
client.closed = true
client.lock.Unlock()
err := client.conn.Close()
if err != nil {
// Lets log an error, as this is non-fatal
logErrorf("Failed to shut down client connection (%s)", err)
}
}
dcpKillSwitch <- true
<-dcpKillNotify
client.opList.Drain(func(req *memdQRequest) {
if !atomic.CompareAndSwapPointer(&req.waitingIn, unsafe.Pointer(client), nil) {
logWarnf("Encountered an unowned request in a client opMap")
}
req.tryCallback(nil, ErrNetwork)
})
close(client.closeNotify)
}()
}
func (client *memdClient) Close() error {
client.lock.Lock()
client.closed = true
client.lock.Unlock()
return client.conn.Close()
}