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-rw-r--r--contrib/persistent-https/proxy.go190
1 files changed, 190 insertions, 0 deletions
diff --git a/contrib/persistent-https/proxy.go b/contrib/persistent-https/proxy.go
new file mode 100644
index 0000000..bb0cdba
--- /dev/null
+++ b/contrib/persistent-https/proxy.go
@@ -0,0 +1,190 @@
+// Copyright 2012 Google Inc. 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 main
+
+import (
+ "fmt"
+ "log"
+ "net"
+ "net/http"
+ "net/http/httputil"
+ "os"
+ "os/exec"
+ "os/signal"
+ "sync"
+ "syscall"
+ "time"
+)
+
+type Proxy struct {
+ BuildLabel string
+ MaxIdleDuration time.Duration
+ PollUpdateInterval time.Duration
+
+ ul net.Listener
+ httpAddr string
+ httpsAddr string
+}
+
+func (p *Proxy) Run() error {
+ hl, err := net.Listen("tcp", "127.0.0.1:0")
+ if err != nil {
+ return fmt.Errorf("http listen failed: %v", err)
+ }
+ defer hl.Close()
+
+ hsl, err := net.Listen("tcp", "127.0.0.1:0")
+ if err != nil {
+ return fmt.Errorf("https listen failed: %v", err)
+ }
+ defer hsl.Close()
+
+ p.ul, err = DefaultSocket.Listen()
+ if err != nil {
+ c, derr := DefaultSocket.Dial()
+ if derr == nil {
+ c.Close()
+ fmt.Println("OK\nA proxy is already running... exiting")
+ return nil
+ } else if e, ok := derr.(*net.OpError); ok && e.Err == syscall.ECONNREFUSED {
+ // Nothing is listening on the socket, unlink it and try again.
+ syscall.Unlink(DefaultSocket.Path())
+ p.ul, err = DefaultSocket.Listen()
+ }
+ if err != nil {
+ return fmt.Errorf("unix listen failed on %v: %v", DefaultSocket.Path(), err)
+ }
+ }
+ defer p.ul.Close()
+ go p.closeOnSignal()
+ go p.closeOnUpdate()
+
+ p.httpAddr = hl.Addr().String()
+ p.httpsAddr = hsl.Addr().String()
+ fmt.Printf("OK\nListening on unix socket=%v http=%v https=%v\n",
+ p.ul.Addr(), p.httpAddr, p.httpsAddr)
+
+ result := make(chan error, 2)
+ go p.serveUnix(result)
+ go func() {
+ result <- http.Serve(hl, &httputil.ReverseProxy{
+ FlushInterval: 500 * time.Millisecond,
+ Director: func(r *http.Request) {},
+ })
+ }()
+ go func() {
+ result <- http.Serve(hsl, &httputil.ReverseProxy{
+ FlushInterval: 500 * time.Millisecond,
+ Director: func(r *http.Request) {
+ r.URL.Scheme = "https"
+ },
+ })
+ }()
+ return <-result
+}
+
+type socketContext struct {
+ sync.WaitGroup
+ mutex sync.Mutex
+ last time.Time
+}
+
+func (sc *socketContext) Done() {
+ sc.mutex.Lock()
+ defer sc.mutex.Unlock()
+ sc.last = time.Now()
+ sc.WaitGroup.Done()
+}
+
+func (p *Proxy) serveUnix(result chan<- error) {
+ sockCtx := &socketContext{}
+ go p.closeOnIdle(sockCtx)
+
+ var err error
+ for {
+ var uconn net.Conn
+ uconn, err = p.ul.Accept()
+ if err != nil {
+ err = fmt.Errorf("accept failed: %v", err)
+ break
+ }
+ sockCtx.Add(1)
+ go p.handleUnixConn(sockCtx, uconn)
+ }
+ sockCtx.Wait()
+ result <- err
+}
+
+func (p *Proxy) handleUnixConn(sockCtx *socketContext, uconn net.Conn) {
+ defer sockCtx.Done()
+ defer uconn.Close()
+ data := []byte(fmt.Sprintf("%v\n%v", p.httpsAddr, p.httpAddr))
+ uconn.SetDeadline(time.Now().Add(5 * time.Second))
+ for i := 0; i < 2; i++ {
+ if n, err := uconn.Write(data); err != nil {
+ log.Printf("error sending http addresses: %+v\n", err)
+ return
+ } else if n != len(data) {
+ log.Printf("sent %d data bytes, wanted %d\n", n, len(data))
+ return
+ }
+ if _, err := uconn.Read([]byte{0, 0, 0, 0}); err != nil {
+ log.Printf("error waiting for Ack: %+v\n", err)
+ return
+ }
+ }
+ // Wait without a deadline for the client to finish via EOF
+ uconn.SetDeadline(time.Time{})
+ uconn.Read([]byte{0, 0, 0, 0})
+}
+
+func (p *Proxy) closeOnIdle(sockCtx *socketContext) {
+ for d := p.MaxIdleDuration; d > 0; {
+ time.Sleep(d)
+ sockCtx.Wait()
+ sockCtx.mutex.Lock()
+ if d = sockCtx.last.Add(p.MaxIdleDuration).Sub(time.Now()); d <= 0 {
+ log.Println("graceful shutdown from idle timeout")
+ p.ul.Close()
+ }
+ sockCtx.mutex.Unlock()
+ }
+}
+
+func (p *Proxy) closeOnUpdate() {
+ for {
+ time.Sleep(p.PollUpdateInterval)
+ if out, err := exec.Command(os.Args[0], "--print_label").Output(); err != nil {
+ log.Printf("error polling for updated binary: %v\n", err)
+ } else if s := string(out[:len(out)-1]); p.BuildLabel != s {
+ log.Printf("graceful shutdown from updated binary: %q --> %q\n", p.BuildLabel, s)
+ p.ul.Close()
+ break
+ }
+ }
+}
+
+func (p *Proxy) closeOnSignal() {
+ ch := make(chan os.Signal, 10)
+ signal.Notify(ch, os.Interrupt, os.Kill, os.Signal(syscall.SIGTERM), os.Signal(syscall.SIGHUP))
+ sig := <-ch
+ p.ul.Close()
+ switch sig {
+ case os.Signal(syscall.SIGHUP):
+ log.Printf("graceful shutdown from signal: %v\n", sig)
+ default:
+ log.Fatalf("exiting from signal: %v\n", sig)
+ }
+}