Golang codec.NewDecoder函數代碼示例

// readTCP is used to read the start of a TCP stream.
// it decrypts and decompresses the stream if necessary
func (m *Memberlist) readTCP(conn net.Conn) (messageType, io.Reader, *codec.Decoder, error) {
	// Created a buffered reader
	var bufConn io.Reader = bufio.NewReader(conn)

	// Read the message type
	buf := [1]byte{0}
	if _, err := bufConn.Read(buf[:]); err != nil {
		return 0, nil, nil, err
	}
	msgType := messageType(buf[0])

	// Check if the message is encrypted
	if msgType == encryptMsg {
		if !m.config.EncryptionEnabled() {
			return 0, nil, nil,
				fmt.Errorf("Remote state is encrypted and encryption is not configured")
		}

		plain, err := m.decryptRemoteState(bufConn)
		if err != nil {
			return 0, nil, nil, err
		}

		// Reset message type and bufConn
		msgType = messageType(plain[0])
		bufConn = bytes.NewReader(plain[1:])
	} else if m.config.EncryptionEnabled() {
		return 0, nil, nil,
			fmt.Errorf("Encryption is configured but remote state is not encrypted")
	}

	// Get the msgPack decoders
	hd := codec.MsgpackHandle{}
	dec := codec.NewDecoder(bufConn, &hd)

	// Check if we have a compressed message
	if msgType == compressMsg {
		var c compress
		if err := dec.Decode(&c); err != nil {
			return 0, nil, nil, err
		}
		decomp, err := decompressBuffer(&c)
		if err != nil {
			return 0, nil, nil, err
		}

		// Reset the message type
		msgType = messageType(decomp[0])

		// Create a new bufConn
		bufConn = bytes.NewReader(decomp[1:])

		// Create a new decoder
		dec = codec.NewDecoder(bufConn, &hd)
	}

	return msgType, bufConn, dec, nil
}

func decodePeerMsg(buf []byte) []string {
	var data []string
	if err := codec.NewDecoder(bytes.NewReader(buf), &mh).Decode(&data); err != nil {
		kingpin.Errorf("Error while decoding (generic msgpack) message: %s\n", err.Error())
	}
	return data
}

func printMsgPackData(log raft.Log, msgtype string, buf []byte) {
	var data interface{}
	if err := codec.NewDecoder(bytes.NewReader(buf), &mh).Decode(&data); err != nil {
		kingpin.Errorf("Error while decoding (generic msgpack) message: %s\n", err.Error())
	}
	printJson(log, msgtype, data)
}

// joins the raft leader and sets up infrastructure for
// processing commands
// can return ErrNotLeader
func newConnToLeader(conn net.Conn, advertiseAddr string, lg *log.Logger) (*connToLeader, error) {
	// send join command
	h := &codec.MsgpackHandle{}
	ret := &connToLeader{
		c:       conn,
		e:       codec.NewEncoder(conn, h),
		d:       codec.NewDecoder(conn, h),
		l:       new(sync.Mutex),
		lg:      lg,
		pending: make(chan *commandCallback, 64),
	}
	join := &joinReq{
		PeerAddr: advertiseAddr,
	}
	err := ret.e.Encode(join)
	if err != nil {
		ret.c.Close()
		return nil, err
	}
	joinResp := &joinResp{}
	err = ret.d.Decode(joinResp)
	if err != nil {
		ret.lg.Printf("Error connecting to leader at %s : %s", conn.RemoteAddr().String(), err)
		ret.c.Close()
		return nil, err
	}
	go ret.readResponses()
	return ret, nil
}

// handleSnapshotRequest reads the request from the conn and dispatches it. This
// will be called from a goroutine after an incoming stream is determined to be
// a snapshot request.
func (s *Server) handleSnapshotRequest(conn net.Conn) error {
	var args structs.SnapshotRequest
	dec := codec.NewDecoder(conn, &codec.MsgpackHandle{})
	if err := dec.Decode(&args); err != nil {
		return fmt.Errorf("failed to decode request: %v", err)
	}

	var reply structs.SnapshotResponse
	snap, err := s.dispatchSnapshotRequest(&args, conn, &reply)
	if err != nil {
		reply.Error = err.Error()
		goto RESPOND
	}
	defer func() {
		if err := snap.Close(); err != nil {
			s.logger.Printf("[ERR] consul: Failed to close snapshot: %v", err)
		}
	}()

RESPOND:
	enc := codec.NewEncoder(conn, &codec.MsgpackHandle{})
	if err := enc.Encode(&reply); err != nil {
		return fmt.Errorf("failed to encode response: %v", err)
	}
	if snap != nil {
		if _, err := io.Copy(conn, snap); err != nil {
			return fmt.Errorf("failed to stream snapshot: %v", err)
		}
	}

	return nil
}

// getConn is used to get a connection from the pool.
func (n *NetworkTransport) getConn(target string) (*netConn, error) {
	// Check for a pooled conn
	if conn := n.getPooledConn(target); conn != nil {
		return conn, nil
	}

	// Dial a new connection
	conn, err := n.stream.Dial(target, n.timeout)
	if err != nil {
		return nil, err
	}

	// Wrap the conn
	netConn := &netConn{
		target: target,
		conn:   conn,
		r:      bufio.NewReader(conn),
		w:      bufio.NewWriter(conn),
	}

	// Setup encoder/decoders
	netConn.dec = codec.NewDecoder(netConn.r, &codec.MsgpackHandle{})
	netConn.enc = codec.NewEncoder(netConn.w, &codec.MsgpackHandle{})

	// Done
	return netConn, nil
}

// listen is a long running routine that listens for new clients
func (i *AgentRPC) listen() {
	for {
		conn, err := i.listener.Accept()
		if err != nil {
			if i.stop {
				return
			}
			i.logger.Printf("[ERR] agent.rpc: Failed to accept client: %v", err)
			continue
		}
		i.logger.Printf("[INFO] agent.rpc: Accepted client: %v", conn.RemoteAddr())

		// Wrap the connection in a client
		client := &rpcClient{
			name:   conn.RemoteAddr().String(),
			conn:   conn,
			reader: bufio.NewReader(conn),
			writer: bufio.NewWriter(conn),
		}
		client.dec = codec.NewDecoder(client.reader, msgpackHandle)
		client.enc = codec.NewEncoder(client.writer, msgpackHandle)

		// Register the client
		i.Lock()
		if !i.stop {
			i.clients[client.name] = client
			go i.handleClient(client)
		} else {
			conn.Close()
		}
		i.Unlock()
	}
}

func MockDecoder(buf []byte) interface{} {
	out := new(MockData)
	err := codec.NewDecoder(bytes.NewReader(buf), msgpackHandle).Decode(out)
	if err != nil {
		panic(err)
	}
	return out
}

// NewCodec returns a MsgpackCodec that can be used as either
// a Client or Server rpc Codec. It also provides controls for
// enabling and disabling buffering for both reads and writes.
func NewCodec(bufReads, bufWrites bool, conn io.ReadWriteCloser) *MsgpackCodec {
	cc := &MsgpackCodec{
		conn: conn,
	}
	if bufReads {
		cc.bufR = bufio.NewReader(conn)
		cc.dec = codec.NewDecoder(cc.bufR, msgpackHandle)
	} else {
		cc.dec = codec.NewDecoder(cc.conn, msgpackHandle)
	}
	if bufWrites {
		cc.bufW = bufio.NewWriter(conn)
		cc.enc = codec.NewEncoder(cc.bufW, msgpackHandle)
	} else {
		cc.enc = codec.NewEncoder(cc.conn, msgpackHandle)
	}
	return cc
}

// SnapshotRPC is a streaming client function for performing a snapshot RPC
// request to a remote server. It will create a fresh connection for each
// request, send the request header, and then stream in any data from the
// reader (for a restore). It will then parse the received response header, and
// if there's no error will return an io.ReadCloser (that you must close) with
// the streaming output (for a snapshot). If the reply contains an error, this
// will always return an error as well, so you don't need to check the error
// inside the filled-in reply.
func SnapshotRPC(pool *ConnPool, dc string, addr net.Addr,
	args *structs.SnapshotRequest, in io.Reader, reply *structs.SnapshotResponse) (io.ReadCloser, error) {

	conn, hc, err := pool.Dial(dc, addr)
	if err != nil {
		return nil, err
	}

	// keep will disarm the defer on success if we are returning the caller
	// our connection to stream the output.
	var keep bool
	defer func() {
		if !keep {
			conn.Close()
		}
	}()

	// Write the snapshot RPC byte to set the mode, then perform the
	// request.
	if _, err := conn.Write([]byte{byte(rpcSnapshot)}); err != nil {
		return nil, fmt.Errorf("failed to write stream type: %v", err)
	}

	// Push the header encoded as msgpack, then stream the input.
	enc := codec.NewEncoder(conn, &codec.MsgpackHandle{})
	if err := enc.Encode(&args); err != nil {
		return nil, fmt.Errorf("failed to encode request: %v", err)
	}
	if _, err := io.Copy(conn, in); err != nil {
		return nil, fmt.Errorf("failed to copy snapshot in: %v", err)
	}

	// Our RPC protocol requires support for a half-close in order to signal
	// the other side that they are done reading the stream, since we don't
	// know the size in advance. This saves us from having to buffer just to
	// calculate the size.
	if hc != nil {
		if err := hc.CloseWrite(); err != nil {
			return nil, fmt.Errorf("failed to half close snapshot connection: %v", err)
		}
	} else {
		return nil, fmt.Errorf("snapshot connection requires half-close support")
	}

	// Pull the header decoded as msgpack. The caller can continue to read
	// the conn to stream the remaining data.
	dec := codec.NewDecoder(conn, &codec.MsgpackHandle{})
	if err := dec.Decode(reply); err != nil {
		return nil, fmt.Errorf("failed to decode response: %v", err)
	}
	if reply.Error != "" {
		return nil, errors.New(reply.Error)
	}

	keep = true
	return conn, nil
}

func decodeQueryEventRecord(buf []byte) (EventRecord, error) {
	var qr QueryEventRecord
	handle := codec.MsgpackHandle{RawToString: true, WriteExt: true}
	if err := codec.NewDecoder(bytes.NewReader(buf), &handle).Decode(&qr); err != nil {
		log.Printf("decoding failed")
		return nil, err
	}
	return EventRecord(qr), nil
}

// See raft.FSM.
func (m *MockFSM) Restore(in io.ReadCloser) error {
	m.Lock()
	defer m.Unlock()
	defer in.Close()
	hd := codec.MsgpackHandle{}
	dec := codec.NewDecoder(in, &hd)

	m.logs = nil
	return dec.Decode(&m.logs)
}

// decodeTags is used to decode a tag map
func (t *tribe) decodeTags(buf []byte) map[string]string {
	tags := make(map[string]string)
	r := bytes.NewReader(buf)
	dec := codec.NewDecoder(r, &codec.MsgpackHandle{})
	if err := dec.Decode(&tags); err != nil {
		t.logger.WithFields(log.Fields{
			"_block": "decode-tags",
			"error":  err,
		}).Error("Failed to decode tags")
	}
	return tags
}

// decodeTags is used to decode a tag map
func (s *Serf) decodeTags(buf []byte) map[string]string {
	tags := make(map[string]string)

	// Backwards compatibility mode
	if len(buf) == 0 || buf[0] != tagMagicByte {
		tags["role"] = string(buf)
		return tags
	}

	// Decode the tags
	r := bytes.NewReader(buf[1:])
	dec := codec.NewDecoder(r, &codec.MsgpackHandle{})
	if err := dec.Decode(&tags); err != nil {
		s.logger.Printf("[ERR] serf: Failed to decode tags: %v", err)
	}
	return tags
}

// ClientFromConfig is used to create a new RPC client given the
// configuration object. This will return a client, or an error if
// the connection could not be established.
func ClientFromConfig(c *Config) (*RPCClient, error) {
	// Setup the defaults
	if c.Timeout == 0 {
		c.Timeout = DefaultTimeout
	}

	// Try to dial to serf
	conn, err := net.DialTimeout("tcp", c.Addr, c.Timeout)
	if err != nil {
		return nil, err
	}

	// Create the client
	client := &RPCClient{
		seq:        0,
		timeout:    c.Timeout,
		conn:       conn.(*net.TCPConn),
		reader:     bufio.NewReader(conn),
		writer:     bufio.NewWriter(conn),
		dispatch:   make(map[uint64]seqHandler),
		shutdownCh: make(chan struct{}),
	}
	client.dec = codec.NewDecoder(client.reader,
		&codec.MsgpackHandle{RawToString: true, WriteExt: true})
	client.enc = codec.NewEncoder(client.writer,
		&codec.MsgpackHandle{RawToString: true, WriteExt: true})
	go client.listen()

	// Do the initial handshake
	if err := client.handshake(); err != nil {
		client.Close()
		return nil, err
	}

	// Do the initial authentication if needed
	if c.AuthKey != "" {
		if err := client.auth(c.AuthKey); err != nil {
			client.Close()
			return nil, err
		}
	}

	return client, err
}