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redcon.go
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redcon.go
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// Package redcon implements a Redis compatible server framework
package redis
import (
"bufio"
"crypto/tls"
"errors"
"io"
"net"
"sync"
)
var (
errUnbalancedQuotes = &errProtocol{"unbalanced quotes in request"}
errInvalidBulkLength = &errProtocol{"invalid bulk length"}
errInvalidMultiBulkLength = &errProtocol{"invalid multibulk length"}
errDetached = errors.New("detached")
errIncompleteCommand = errors.New("incomplete command")
errTooMuchData = errors.New("too much data")
)
type errProtocol struct {
msg string
}
func (err *errProtocol) Error() string {
return "Protocol error: " + err.msg
}
// Conn represents a client connection
type RedisConn interface {
// RemoteAddr returns the remote address of the client connection.
RemoteAddr() string
// Close closes the connection.
Close() error
// WriteError writes an error to the client.
WriteError(msg string)
// WriteString writes a string to the client.
WriteString(str string)
// WriteBulk writes bulk bytes to the client.
WriteBulk(bulk []byte)
// WriteBulkString writes a bulk string to the client.
WriteBulkString(bulk string)
// WriteInt writes an integer to the client.
WriteInt(num int)
// WriteInt64 writes a 64-but signed integer to the client.
WriteInt64(num int64)
// WriteArray writes an array header. You must then write additional
// sub-responses to the client to complete the response.
// For example to write two strings:
//
// c.WriteArray(2)
// c.WriteBulk("item 1")
// c.WriteBulk("item 2")
WriteArray(count int)
// WriteNull writes a null to the client
WriteNull()
// WriteRaw writes raw data to the client.
WriteRaw(data []byte)
// Context returns a user-defined context
Context() interface{}
// SetContext sets a user-defined context
SetContext(v interface{})
// SetReadBuffer updates the buffer read size for the connection
SetReadBuffer(bytes int)
// Detach return a connection that is detached from the server.
// Useful for operations like PubSub.
//
// dconn := conn.Detach()
// go func(){
// defer dconn.Close()
// cmd, err := dconn.ReadCommand()
// if err != nil{
// fmt.Printf("read failed: %v\n", err)
// return
// }
// fmt.Printf("received command: %v", cmd)
// hconn.WriteString("OK")
// if err := dconn.Flush(); err != nil{
// fmt.Printf("write failed: %v\n", err)
// return
// }
// }()
Detach() DetachedConn
// ReadPipeline returns all commands in current pipeline, if any
// The commands are removed from the pipeline.
ReadPipeline() []Command
// PeekPipeline returns all commands in current pipeline, if any.
// The commands remain in the pipeline.
PeekPipeline() []Command
// NetConn returns the base net.Conn connection
NetConn() net.Conn
}
// NewServer returns a new Redcon server configured on "tcp" network net.
func NewServer(addr string,
handler func(conn RedisConn, cmd Command),
accept func(conn RedisConn) bool,
closed func(conn RedisConn, err error),
) *Server {
return NewServerNetwork("tcp", addr, handler, accept, closed)
}
// NewServerTLS returns a new Redcon TLS server configured on "tcp" network net.
func NewServerTLS(addr string,
handler func(conn RedisConn, cmd Command),
accept func(conn RedisConn) bool,
closed func(conn RedisConn, err error),
config *tls.Config,
) *TLSServer {
return NewServerNetworkTLS("tcp", addr, handler, accept, closed, config)
}
// NewServerNetwork returns a new Redcon server. The network net must be
// a stream-oriented network: "tcp", "tcp4", "tcp6", "unix" or "unixpacket"
func NewServerNetwork(
net, laddr string,
handler func(conn RedisConn, cmd Command),
accept func(conn RedisConn) bool,
closed func(conn RedisConn, err error),
) *Server {
if handler == nil {
panic("handler is nil")
}
s := &Server{
net: net,
laddr: laddr,
handler: handler,
accept: accept,
closed: closed,
conns: make(map[*conn]bool),
}
return s
}
// NewServerNetworkTLS returns a new TLS Redcon server. The network net must be
// a stream-oriented network: "tcp", "tcp4", "tcp6", "unix" or "unixpacket"
func NewServerNetworkTLS(
net, laddr string,
handler func(conn RedisConn, cmd Command),
accept func(conn RedisConn) bool,
closed func(conn RedisConn, err error),
config *tls.Config,
) *TLSServer {
if handler == nil {
panic("handler is nil")
}
s := Server{
net: net,
laddr: laddr,
handler: handler,
accept: accept,
closed: closed,
conns: make(map[*conn]bool),
}
tls := &TLSServer{
config: config,
Server: &s,
}
return tls
}
// Close stops listening on the TCP address.
// Already Accepted connections will be closed.
func (s *Server) Close() error {
s.mu.Lock()
defer s.mu.Unlock()
if s.ln == nil {
return errors.New("not serving")
}
s.done = true
return s.ln.Close()
}
// ListenAndServe serves incoming connections.
func (s *Server) ListenAndServe() error {
return s.ListenServeAndSignal(nil)
}
// Addr returns server's listen address
func (s *Server) Addr() net.Addr {
return s.ln.Addr()
}
// Close stops listening on the TCP address.
// Already Accepted connections will be closed.
func (s *TLSServer) Close() error {
s.mu.Lock()
defer s.mu.Unlock()
if s.ln == nil {
return errors.New("not serving")
}
s.done = true
return s.ln.Close()
}
// ListenAndServe serves incoming connections.
func (s *TLSServer) ListenAndServe() error {
return s.ListenServeAndSignal(nil)
}
// ListenAndServe creates a new server and binds to addr configured on "tcp" network net.
func ListenAndServe(addr string,
handler func(conn RedisConn, cmd Command),
accept func(conn RedisConn) bool,
closed func(conn RedisConn, err error),
) error {
return ListenAndServeNetwork("tcp", addr, handler, accept, closed)
}
// ListenAndServeTLS creates a new TLS server and binds to addr configured on "tcp" network net.
func ListenAndServeTLS(addr string,
handler func(conn RedisConn, cmd Command),
accept func(conn RedisConn) bool,
closed func(conn RedisConn, err error),
config *tls.Config,
) error {
return ListenAndServeNetworkTLS("tcp", addr, handler, accept, closed, config)
}
// ListenAndServeNetwork creates a new server and binds to addr. The network net must be
// a stream-oriented network: "tcp", "tcp4", "tcp6", "unix" or "unixpacket"
func ListenAndServeNetwork(
net, laddr string,
handler func(conn RedisConn, cmd Command),
accept func(conn RedisConn) bool,
closed func(conn RedisConn, err error),
) error {
return NewServerNetwork(net, laddr, handler, accept, closed).ListenAndServe()
}
// ListenAndServeNetworkTLS creates a new TLS server and binds to addr. The network net must be
// a stream-oriented network: "tcp", "tcp4", "tcp6", "unix" or "unixpacket"
func ListenAndServeNetworkTLS(
net, laddr string,
handler func(conn RedisConn, cmd Command),
accept func(conn RedisConn) bool,
closed func(conn RedisConn, err error),
config *tls.Config,
) error {
return NewServerNetworkTLS(net, laddr, handler, accept, closed, config).ListenAndServe()
}
// ListenServeAndSignal serves incoming connections and passes nil or error
// when listening. signal can be nil.
func (s *Server) ListenServeAndSignal(signal chan error) error {
ln, err := net.Listen(s.net, s.laddr)
if err != nil {
if signal != nil {
signal <- err
}
return err
}
s.ln = ln
if signal != nil {
signal <- nil
}
return serve(s)
}
// ListenServeAndSignal serves incoming connections and passes nil or error
// when listening. signal can be nil.
func (s *TLSServer) ListenServeAndSignal(signal chan error) error {
ln, err := tls.Listen(s.net, s.laddr, s.config)
if err != nil {
if signal != nil {
signal <- err
}
return err
}
s.ln = ln
if signal != nil {
signal <- nil
}
return serve(s.Server)
}
func serve(s *Server) error {
defer func() {
s.ln.Close()
func() {
s.mu.Lock()
defer s.mu.Unlock()
for c := range s.conns {
c.Close()
}
s.conns = nil
}()
}()
for {
lnconn, err := s.ln.Accept()
if err != nil {
s.mu.Lock()
done := s.done
s.mu.Unlock()
if done {
return nil
}
return err
}
c := &conn{
conn: lnconn,
addr: lnconn.RemoteAddr().String(),
wr: NewWriter(lnconn),
rd: NewReader(lnconn),
}
s.mu.Lock()
s.conns[c] = true
s.mu.Unlock()
if s.accept != nil && !s.accept(c) {
s.mu.Lock()
delete(s.conns, c)
s.mu.Unlock()
c.Close()
continue
}
go handle(s, c)
}
}
// handle manages the server connection.
func handle(s *Server, c *conn) {
var err error
defer func() {
if err != errDetached {
// do not close the connection when a detach is detected.
c.conn.Close()
}
func() {
// remove the conn from the server
s.mu.Lock()
defer s.mu.Unlock()
delete(s.conns, c)
if s.closed != nil {
if err == io.EOF {
err = nil
}
s.closed(c, err)
}
}()
}()
err = func() error {
// read commands and feed back to the client
for {
// read pipeline commands
cmds, err := c.rd.readCommands(nil)
if err != nil {
if err, ok := err.(*errProtocol); ok {
// All protocol errors should attempt a response to
// the client. Ignore write errors.
c.wr.WriteError("ERR " + err.Error())
c.wr.Flush()
}
return err
}
c.cmds = cmds
for len(c.cmds) > 0 {
cmd := c.cmds[0]
if len(c.cmds) == 1 {
c.cmds = nil
} else {
c.cmds = c.cmds[1:]
}
s.handler(c, cmd)
}
if c.detached {
// client has been detached
return errDetached
}
if c.closed {
return nil
}
if err := c.wr.Flush(); err != nil {
return err
}
}
}()
}
// conn represents a client connection
type conn struct {
conn net.Conn
wr *Writer
rd *Reader
addr string
ctx interface{}
detached bool
closed bool
cmds []Command
}
func (c *conn) Close() error {
c.wr.Flush()
c.closed = true
return c.conn.Close()
}
func (c *conn) Context() interface{} { return c.ctx }
func (c *conn) SetContext(v interface{}) { c.ctx = v }
func (c *conn) SetReadBuffer(n int) {}
func (c *conn) WriteString(str string) { c.wr.WriteString(str) }
func (c *conn) WriteBulk(bulk []byte) { c.wr.WriteBulk(bulk) }
func (c *conn) WriteBulkString(bulk string) { c.wr.WriteBulkString(bulk) }
func (c *conn) WriteInt(num int) { c.wr.WriteInt(num) }
func (c *conn) WriteInt64(num int64) { c.wr.WriteInt64(num) }
func (c *conn) WriteError(msg string) { c.wr.WriteError(msg) }
func (c *conn) WriteArray(count int) { c.wr.WriteArray(count) }
func (c *conn) WriteNull() { c.wr.WriteNull() }
func (c *conn) WriteRaw(data []byte) { c.wr.WriteRaw(data) }
func (c *conn) RemoteAddr() string { return c.addr }
func (c *conn) ReadPipeline() []Command {
cmds := c.cmds
c.cmds = nil
return cmds
}
func (c *conn) PeekPipeline() []Command {
return c.cmds
}
func (c *conn) NetConn() net.Conn {
return c.conn
}
// BaseWriter returns the underlying connection writer, if any
func BaseWriter(c RedisConn) *Writer {
if c, ok := c.(*conn); ok {
return c.wr
}
return nil
}
// DetachedConn represents a connection that is detached from the server
type DetachedConn interface {
// RedisConn is the original connection
RedisConn
// ReadCommand reads the next client command.
ReadCommand() (Command, error)
// Flush flushes any writes to the network.
Flush() error
}
// Detach removes the current connection from the server loop and returns
// a detached connection. This is useful for operations such as PubSub.
// The detached connection must be closed by calling Close() when done.
// All writes such as WriteString() will not be written to the client
// until Flush() is called.
func (c *conn) Detach() DetachedConn {
c.detached = true
cmds := c.cmds
c.cmds = nil
return &detachedConn{conn: c, cmds: cmds}
}
type detachedConn struct {
*conn
cmds []Command
}
// Flush writes and Write* calls to the client.
func (dc *detachedConn) Flush() error {
return dc.conn.wr.Flush()
}
// ReadCommand read the next command from the client.
func (dc *detachedConn) ReadCommand() (Command, error) {
if dc.closed {
return Command{}, errors.New("closed")
}
if len(dc.cmds) > 0 {
cmd := dc.cmds[0]
if len(dc.cmds) == 1 {
dc.cmds = nil
} else {
dc.cmds = dc.cmds[1:]
}
return cmd, nil
}
cmd, err := dc.rd.ReadCommand()
if err != nil {
return Command{}, err
}
return cmd, nil
}
// Command represent a command
type Command struct {
// Raw is a encoded RESP message.
Raw []byte
// Args is a series of arguments that make up the command.
Args [][]byte
}
// Server defines a server for clients for managing client connections.
type Server struct {
mu sync.Mutex
net string
laddr string
handler func(conn RedisConn, cmd Command)
accept func(conn RedisConn) bool
closed func(conn RedisConn, err error)
conns map[*conn]bool
ln net.Listener
done bool
}
// TLSServer defines a server for clients for managing client connections.
type TLSServer struct {
*Server
config *tls.Config
}
// Writer allows for writing RESP messages.
type Writer struct {
w io.Writer
b []byte
}
// NewWriter creates a new RESP writer.
func NewWriter(wr io.Writer) *Writer {
return &Writer{
w: wr,
}
}
// WriteNull writes a null to the client
func (w *Writer) WriteNull() {
w.b = AppendNull(w.b)
}
// WriteArray writes an array header. You must then write additional
// sub-responses to the client to complete the response.
// For example to write two strings:
//
// c.WriteArray(2)
// c.WriteBulk("item 1")
// c.WriteBulk("item 2")
func (w *Writer) WriteArray(count int) {
w.b = AppendArray(w.b, count)
}
// WriteBulk writes bulk bytes to the client.
func (w *Writer) WriteBulk(bulk []byte) {
w.b = AppendBulk(w.b, bulk)
}
// WriteBulkString writes a bulk string to the client.
func (w *Writer) WriteBulkString(bulk string) {
w.b = AppendBulkString(w.b, bulk)
}
// Buffer returns the unflushed buffer. This is a copy so changes
// to the resulting []byte will not affect the writer.
func (w *Writer) Buffer() []byte {
return append([]byte(nil), w.b...)
}
// SetBuffer replaces the unflushed buffer with new bytes.
func (w *Writer) SetBuffer(raw []byte) {
w.b = w.b[:0]
w.b = append(w.b, raw...)
}
// Flush writes all unflushed Write* calls to the underlying writer.
func (w *Writer) Flush() error {
if _, err := w.w.Write(w.b); err != nil {
return err
}
w.b = w.b[:0]
return nil
}
// WriteError writes an error to the client.
func (w *Writer) WriteError(msg string) {
w.b = AppendError(w.b, msg)
}
// WriteString writes a string to the client.
func (w *Writer) WriteString(msg string) {
w.b = AppendString(w.b, msg)
}
// WriteInt writes an integer to the client.
func (w *Writer) WriteInt(num int) {
w.WriteInt64(int64(num))
}
// WriteInt64 writes a 64-bit signed integer to the client.
func (w *Writer) WriteInt64(num int64) {
w.b = AppendInt(w.b, num)
}
// WriteRaw writes raw data to the client.
func (w *Writer) WriteRaw(data []byte) {
w.b = append(w.b, data...)
}
// Reader represent a reader for RESP or telnet commands.
type Reader struct {
rd *bufio.Reader
buf []byte
start int
end int
cmds []Command
}
// NewReader returns a command reader which will read RESP or telnet commands.
func NewReader(rd io.Reader) *Reader {
return &Reader{
rd: bufio.NewReader(rd),
buf: make([]byte, 4096),
}
}
func parseInt(b []byte) (int, bool) {
if len(b) == 1 && b[0] >= '0' && b[0] <= '9' {
return int(b[0] - '0'), true
}
var n int
var sign bool
var i int
if len(b) > 0 && b[0] == '-' {
sign = true
i++
}
for ; i < len(b); i++ {
if b[i] < '0' || b[i] > '9' {
return 0, false
}
n = n*10 + int(b[i]-'0')
}
if sign {
n *= -1
}
return n, true
}
func (rd *Reader) readCommands(leftover *int) ([]Command, error) {
var cmds []Command
b := rd.buf[rd.start:rd.end]
if rd.end-rd.start == 0 && len(rd.buf) > 4096 {
rd.buf = rd.buf[:4096]
rd.start = 0
rd.end = 0
}
if len(b) > 0 {
// we have data, yay!
// but is this enough data for a complete command? or multiple?
next:
switch b[0] {
default:
// just a plain text command
for i := 0; i < len(b); i++ {
if b[i] == '\n' {
var line []byte
if i > 0 && b[i-1] == '\r' {
line = b[:i-1]
} else {
line = b[:i]
}
var cmd Command
var quote bool
var quotech byte
var escape bool
outer:
for {
nline := make([]byte, 0, len(line))
for i := 0; i < len(line); i++ {
c := line[i]
if !quote {
if c == ' ' {
if len(nline) > 0 {
cmd.Args = append(cmd.Args, nline)
}
line = line[i+1:]
continue outer
}
if c == '"' || c == '\'' {
if i != 0 {
return nil, errUnbalancedQuotes
}
quotech = c
quote = true
line = line[i+1:]
continue outer
}
} else {
if escape {
escape = false
switch c {
case 'n':
c = '\n'
case 'r':
c = '\r'
case 't':
c = '\t'
}
} else if c == quotech {
quote = false
quotech = 0
cmd.Args = append(cmd.Args, nline)
line = line[i+1:]
if len(line) > 0 && line[0] != ' ' {
return nil, errUnbalancedQuotes
}
continue outer
} else if c == '\\' {
escape = true
continue
}
}
nline = append(nline, c)
}
if quote {
return nil, errUnbalancedQuotes
}
if len(line) > 0 {
cmd.Args = append(cmd.Args, line)
}
break
}
if len(cmd.Args) > 0 {
// convert this to resp command syntax
var wr Writer
wr.WriteArray(len(cmd.Args))
for i := range cmd.Args {
wr.WriteBulk(cmd.Args[i])
cmd.Args[i] = append([]byte(nil), cmd.Args[i]...)
}
cmd.Raw = wr.b
cmds = append(cmds, cmd)
}
b = b[i+1:]
if len(b) > 0 {
goto next
} else {
goto done
}
}
}
case '*':
// resp formatted command
marks := make([]int, 0, 16)
outer2:
for i := 1; i < len(b); i++ {
if b[i] == '\n' {
if b[i-1] != '\r' {
return nil, errInvalidMultiBulkLength
}
count, ok := parseInt(b[1 : i-1])
if !ok || count <= 0 {
return nil, errInvalidMultiBulkLength
}
marks = marks[:0]
for j := 0; j < count; j++ {
// read bulk length
i++
if i < len(b) {
if b[i] != '$' {
return nil, &errProtocol{"expected '$', got '" +
string(b[i]) + "'"}
}
si := i
for ; i < len(b); i++ {
if b[i] == '\n' {
if b[i-1] != '\r' {
return nil, errInvalidBulkLength
}
size, ok := parseInt(b[si+1 : i-1])
if !ok || size < 0 {
return nil, errInvalidBulkLength
}
if i+size+2 >= len(b) {
// not ready
break outer2
}
if b[i+size+2] != '\n' ||
b[i+size+1] != '\r' {
return nil, errInvalidBulkLength
}
i++
marks = append(marks, i, i+size)
i += size + 1
break
}
}
}
}
if len(marks) == count*2 {
var cmd Command
if rd.rd != nil {
// make a raw copy of the entire command when
// there's a underlying reader.
cmd.Raw = append([]byte(nil), b[:i+1]...)
} else {
// just assign the slice
cmd.Raw = b[:i+1]
}
cmd.Args = make([][]byte, len(marks)/2)
// slice up the raw command into the args based on
// the recorded marks.
for h := 0; h < len(marks); h += 2 {
cmd.Args[h/2] = cmd.Raw[marks[h]:marks[h+1]]
}
cmds = append(cmds, cmd)
b = b[i+1:]
if len(b) > 0 {
goto next
} else {
goto done
}
}
}
}
}
done:
rd.start = rd.end - len(b)
}
if leftover != nil {
*leftover = rd.end - rd.start
}
if len(cmds) > 0 {
return cmds, nil
}
if rd.rd == nil {
return nil, errIncompleteCommand
}
if rd.end == len(rd.buf) {
// at the end of the buffer.
if rd.start == rd.end {
// rewind the to the beginning
rd.start, rd.end = 0, 0
} else {
// must grow the buffer
newbuf := make([]byte, len(rd.buf)*2)
copy(newbuf, rd.buf)
rd.buf = newbuf
}
}
n, err := rd.rd.Read(rd.buf[rd.end:])
if err != nil {
return nil, err
}
rd.end += n
return rd.readCommands(leftover)
}
// ReadCommand reads the next command.
func (rd *Reader) ReadCommand() (Command, error) {
if len(rd.cmds) > 0 {
cmd := rd.cmds[0]
rd.cmds = rd.cmds[1:]
return cmd, nil
}
cmds, err := rd.readCommands(nil)
if err != nil {
return Command{}, err
}
rd.cmds = cmds
return rd.ReadCommand()
}
// Parse parses a raw RESP message and returns a command.
func Parse(raw []byte) (Command, error) {
rd := Reader{buf: raw, end: len(raw)}
var leftover int
cmds, err := rd.readCommands(&leftover)
if err != nil {
return Command{}, err
}
if leftover > 0 {
return Command{}, errTooMuchData
}
return cmds[0], nil
}