serve grpc and http on the same socket

Signed-off-by: Antonio Murdaca <runcom@redhat.com>

vendor/github.com/soheilhy/cmux/cmux.go

@@ -0,0 +1,269 @@
+// Copyright 2016 The CMux Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+// implied. See the License for the specific language governing
+// permissions and limitations under the License.
+
+package cmux
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"sync"
+	"time"
+)
+
+// Matcher matches a connection based on its content.
+type Matcher func(io.Reader) bool
+
+// MatchWriter is a match that can also write response (say to do handshake).
+type MatchWriter func(io.Writer, io.Reader) bool
+
+// ErrorHandler handles an error and returns whether
+// the mux should continue serving the listener.
+type ErrorHandler func(error) bool
+
+var _ net.Error = ErrNotMatched{}
+
+// ErrNotMatched is returned whenever a connection is not matched by any of
+// the matchers registered in the multiplexer.
+type ErrNotMatched struct {
+	c net.Conn
+}
+
+func (e ErrNotMatched) Error() string {
+	return fmt.Sprintf("mux: connection %v not matched by an matcher",
+		e.c.RemoteAddr())
+}
+
+// Temporary implements the net.Error interface.
+func (e ErrNotMatched) Temporary() bool { return true }
+
+// Timeout implements the net.Error interface.
+func (e ErrNotMatched) Timeout() bool { return false }
+
+type errListenerClosed string
+
+func (e errListenerClosed) Error() string   { return string(e) }
+func (e errListenerClosed) Temporary() bool { return false }
+func (e errListenerClosed) Timeout() bool   { return false }
+
+// ErrListenerClosed is returned from muxListener.Accept when the underlying
+// listener is closed.
+var ErrListenerClosed = errListenerClosed("mux: listener closed")
+
+// for readability of readTimeout
+var noTimeout time.Duration
+
+// New instantiates a new connection multiplexer.
+func New(l net.Listener) CMux {
+	return &cMux{
+		root:        l,
+		bufLen:      1024,
+		errh:        func(_ error) bool { return true },
+		donec:       make(chan struct{}),
+		readTimeout: noTimeout,
+	}
+}
+
+// CMux is a multiplexer for network connections.
+type CMux interface {
+	// Match returns a net.Listener that sees (i.e., accepts) only
+	// the connections matched by at least one of the matcher.
+	//
+	// The order used to call Match determines the priority of matchers.
+	Match(...Matcher) net.Listener
+	// MatchWithWriters returns a net.Listener that accepts only the
+	// connections that matched by at least of the matcher writers.
+	//
+	// Prefer Matchers over MatchWriters, since the latter can write on the
+	// connection before the actual handler.
+	//
+	// The order used to call Match determines the priority of matchers.
+	MatchWithWriters(...MatchWriter) net.Listener
+	// Serve starts multiplexing the listener. Serve blocks and perhaps
+	// should be invoked concurrently within a go routine.
+	Serve() error
+	// HandleError registers an error handler that handles listener errors.
+	HandleError(ErrorHandler)
+	// sets a timeout for the read of matchers
+	SetReadTimeout(time.Duration)
+}
+
+type matchersListener struct {
+	ss []MatchWriter
+	l  muxListener
+}
+
+type cMux struct {
+	root        net.Listener
+	bufLen      int
+	errh        ErrorHandler
+	donec       chan struct{}
+	sls         []matchersListener
+	readTimeout time.Duration
+}
+
+func matchersToMatchWriters(matchers []Matcher) []MatchWriter {
+	mws := make([]MatchWriter, 0, len(matchers))
+	for _, m := range matchers {
+		mws = append(mws, func(w io.Writer, r io.Reader) bool {
+			return m(r)
+		})
+	}
+	return mws
+}
+
+func (m *cMux) Match(matchers ...Matcher) net.Listener {
+	mws := matchersToMatchWriters(matchers)
+	return m.MatchWithWriters(mws...)
+}
+
+func (m *cMux) MatchWithWriters(matchers ...MatchWriter) net.Listener {
+	ml := muxListener{
+		Listener: m.root,
+		connc:    make(chan net.Conn, m.bufLen),
+	}
+	m.sls = append(m.sls, matchersListener{ss: matchers, l: ml})
+	return ml
+}
+
+func (m *cMux) SetReadTimeout(t time.Duration) {
+	m.readTimeout = t
+}
+
+func (m *cMux) Serve() error {
+	var wg sync.WaitGroup
+
+	defer func() {
+		close(m.donec)
+		wg.Wait()
+
+		for _, sl := range m.sls {
+			close(sl.l.connc)
+			// Drain the connections enqueued for the listener.
+			for c := range sl.l.connc {
+				_ = c.Close()
+			}
+		}
+	}()
+
+	for {
+		c, err := m.root.Accept()
+		if err != nil {
+			if !m.handleErr(err) {
+				return err
+			}
+			continue
+		}
+
+		wg.Add(1)
+		go m.serve(c, m.donec, &wg)
+	}
+}
+
+func (m *cMux) serve(c net.Conn, donec <-chan struct{}, wg *sync.WaitGroup) {
+	defer wg.Done()
+
+	muc := newMuxConn(c)
+	if m.readTimeout > noTimeout {
+		_ = c.SetReadDeadline(time.Now().Add(m.readTimeout))
+	}
+	for _, sl := range m.sls {
+		for _, s := range sl.ss {
+			matched := s(muc.Conn, muc.startSniffing())
+			if matched {
+				muc.doneSniffing()
+				if m.readTimeout > noTimeout {
+					_ = c.SetReadDeadline(time.Time{})
+				}
+				select {
+				case sl.l.connc <- muc:
+				case <-donec:
+					_ = c.Close()
+				}
+				return
+			}
+		}
+	}
+
+	_ = c.Close()
+	err := ErrNotMatched{c: c}
+	if !m.handleErr(err) {
+		_ = m.root.Close()
+	}
+}
+
+func (m *cMux) HandleError(h ErrorHandler) {
+	m.errh = h
+}
+
+func (m *cMux) handleErr(err error) bool {
+	if !m.errh(err) {
+		return false
+	}
+
+	if ne, ok := err.(net.Error); ok {
+		return ne.Temporary()
+	}
+
+	return false
+}
+
+type muxListener struct {
+	net.Listener
+	connc chan net.Conn
+}
+
+func (l muxListener) Accept() (net.Conn, error) {
+	c, ok := <-l.connc
+	if !ok {
+		return nil, ErrListenerClosed
+	}
+	return c, nil
+}
+
+// MuxConn wraps a net.Conn and provides transparent sniffing of connection data.
+type MuxConn struct {
+	net.Conn
+	buf bufferedReader
+}
+
+func newMuxConn(c net.Conn) *MuxConn {
+	return &MuxConn{
+		Conn: c,
+		buf:  bufferedReader{source: c},
+	}
+}
+
+// From the io.Reader documentation:
+//
+// When Read encounters an error or end-of-file condition after
+// successfully reading n > 0 bytes, it returns the number of
+// bytes read.  It may return the (non-nil) error from the same call
+// or return the error (and n == 0) from a subsequent call.
+// An instance of this general case is that a Reader returning
+// a non-zero number of bytes at the end of the input stream may
+// return either err == EOF or err == nil.  The next Read should
+// return 0, EOF.
+func (m *MuxConn) Read(p []byte) (int, error) {
+	return m.buf.Read(p)
+}
+
+func (m *MuxConn) startSniffing() io.Reader {
+	m.buf.reset(true)
+	return &m.buf
+}
+
+func (m *MuxConn) doneSniffing() {
+	m.buf.reset(false)
+}