func (self *log) appendRequest(request *protocol.Request, shardId uint32) error {
bytes, err := request.Encode()
if err != nil {
return err
}
// every request is preceded with the length, shard id and the request number
hdr := &entryHeader{
shardId: shardId,
requestNumber: request.GetRequestNumber(),
length: uint32(len(bytes)),
}
writtenHdrBytes, err := hdr.Write(self.file)
if err != nil {
logger.Error("Error while writing header: %s", err)
return err
}
written, err := self.file.Write(bytes)
if err != nil {
logger.Error("Error while writing request: %s", err)
return err
}
if written < len(bytes) {
err = fmt.Errorf("Couldn't write entire request")
logger.Error("Error while writing request: %s", err)
return err
}
self.fileSize += uint64(writtenHdrBytes + written)
return nil
}
// Makes a request to the server. If the responseStream chan is not nil it will expect a response from the server
// with a matching request.Id. The REQUEST_RETRY_ATTEMPTS constant of 3 and the RECONNECT_RETRY_WAIT of 100ms means
// that an attempt to make a request to a downed server will take 300ms to time out.
func (self *ProtobufClient) MakeRequest(request *protocol.Request, r cluster.ResponseChannel) error {
if request.Id == nil {
id := atomic.AddUint32(&self.lastRequestId, uint32(1))
request.Id = &id
}
if r != nil {
self.requestBufferLock.Lock()
// this should actually never happen. The sweeper should clear out dead requests
// before the uint32 ids roll over.
if oldReq, alreadyHasRequestById := self.requestBuffer[*request.Id]; alreadyHasRequestById {
message := "already has a request with this id, must have timed out"
log.Error(message)
oldReq.r.Yield(&protocol.Response{
Type: protocol.Response_ERROR.Enum(),
ErrorMessage: &message,
})
}
self.requestBuffer[*request.Id] = &runningRequest{timeMade: time.Now(), r: r, request: request}
self.requestBufferLock.Unlock()
}
data, err := request.Encode()
if err != nil {
return err
}
conn := self.getConnection()
if conn == nil {
conn = self.reconnect()
if conn == nil {
return fmt.Errorf("Failed to connect to server %s", self.hostAndPort)
}
}
if self.writeTimeout > 0 {
conn.SetWriteDeadline(time.Now().Add(self.writeTimeout))
}
buff := bytes.NewBuffer(make([]byte, 0, len(data)+8))
binary.Write(buff, binary.LittleEndian, uint32(len(data)))
buff.Write(data)
_, err = conn.Write(buff.Bytes())
if err == nil {
return nil
}
// if we got here it errored out, clear out the request
self.requestBufferLock.Lock()
delete(self.requestBuffer, *request.Id)
self.requestBufferLock.Unlock()
self.reconnect()
return err
}