// readUserMsg is used to decode a userMsg from a TCP stream
func (m *Memberlist) readUserMsg(bufConn io.Reader, dec *codec.Decoder) error {
// Read the user message header
var header userMsgHeader
if err := dec.Decode(&header); err != nil {
return err
}
// Read the user message into a buffer
var userBuf []byte
if header.UserMsgLen > 0 {
userBuf = make([]byte, header.UserMsgLen)
bytes, err := io.ReadAtLeast(bufConn, userBuf, header.UserMsgLen)
if err == nil && bytes != header.UserMsgLen {
err = fmt.Errorf(
"Failed to read full user message (%d / %d)",
bytes, header.UserMsgLen)
}
if err != nil {
return err
}
d := m.config.Delegate
if d != nil {
d.NotifyMsg(userBuf)
}
}
return nil
}
// Deserialize is used to deserialize the time table
// and restore the state
func (t *TimeTable) Deserialize(dec *codec.Decoder) error {
// Decode the table
var table []TimeTableEntry
if err := dec.Decode(&table); err != nil {
return err
}
// Witness from oldest to newest
n := len(table)
for i := n - 1; i >= 0; i-- {
t.Witness(table[i].Index, table[i].Time)
}
return nil
}
// readRemoteState is used to read the remote state from a connection
func (m *Memberlist) readRemoteState(bufConn io.Reader, dec *codec.Decoder) (bool, []pushNodeState, []byte, error) {
// Read the push/pull header
var header pushPullHeader
if err := dec.Decode(&header); err != nil {
return false, nil, nil, err
}
// Allocate space for the transfer
remoteNodes := make([]pushNodeState, header.Nodes)
// Try to decode all the states
for i := 0; i < header.Nodes; i++ {
if err := dec.Decode(&remoteNodes[i]); err != nil {
return false, nil, nil, err
}
}
// Read the remote user state into a buffer
var userBuf []byte
if header.UserStateLen > 0 {
userBuf = make([]byte, header.UserStateLen)
bytes, err := io.ReadAtLeast(bufConn, userBuf, header.UserStateLen)
if err == nil && bytes != header.UserStateLen {
err = fmt.Errorf(
"Failed to read full user state (%d / %d)",
bytes, header.UserStateLen)
}
if err != nil {
return false, nil, nil, err
}
}
// For proto versions < 2, there is no port provided. Mask old
// behavior by using the configured port
for idx := range remoteNodes {
if m.ProtocolVersion() < 2 || remoteNodes[idx].Port == 0 {
remoteNodes[idx].Port = uint16(m.config.BindPort)
}
}
return header.Join, remoteNodes, userBuf, nil
}
// handleCommand is used to decode and dispatch a single command.
func (n *NetworkTransport) handleCommand(r *bufio.Reader, dec *codec.Decoder, enc *codec.Encoder) error {
// Get the rpc type
rpcType, err := r.ReadByte()
if err != nil {
return err
}
// Create the RPC object
respCh := make(chan RPCResponse, 1)
rpc := RPC{
RespChan: respCh,
}
// Decode the command
isHeartbeat := false
switch rpcType {
case rpcAppendEntries:
var req AppendEntriesRequest
if err := dec.Decode(&req); err != nil {
return err
}
rpc.Command = &req
// Check if this is a heartbeat
if req.Term != 0 && req.Leader != nil &&
req.PrevLogEntry == 0 && req.PrevLogTerm == 0 &&
len(req.Entries) == 0 && req.LeaderCommitIndex == 0 {
isHeartbeat = true
}
case rpcRequestVote:
var req RequestVoteRequest
if err := dec.Decode(&req); err != nil {
return err
}
rpc.Command = &req
case rpcInstallSnapshot:
var req InstallSnapshotRequest
if err := dec.Decode(&req); err != nil {
return err
}
rpc.Command = &req
rpc.Reader = io.LimitReader(r, req.Size)
default:
return fmt.Errorf("unknown rpc type %d", rpcType)
}
// Check for heartbeat fast-path
if isHeartbeat {
n.heartbeatFnLock.Lock()
fn := n.heartbeatFn
n.heartbeatFnLock.Unlock()
if fn != nil {
fn(rpc)
goto RESP
}
}
// Dispatch the RPC
select {
case n.consumeCh <- rpc:
case <-n.shutdownCh:
return ErrTransportShutdown
}
// Wait for response
RESP:
select {
case resp := <-respCh:
// Send the error first
respErr := ""
if resp.Error != nil {
respErr = resp.Error.Error()
}
if err := enc.Encode(respErr); err != nil {
return err
}
// Send the response
if err := enc.Encode(resp.Response); err != nil {
return err
}
case <-n.shutdownCh:
return ErrTransportShutdown
}
return nil
}