pretend-git/contrib/persistent-https/proxy.go at master · submitgit/pretend-git · GitHub

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// 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)

}

pretend-git/contrib/persistent-https/proxy.go at master · submitgit/pretend-git · GitHub

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