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cmd/tipgodoc: new tip.golang.org server

Rough work in progress. Don't hate.

Change-Id: I9d8247005724a21bdb5d4760cc6135bceb49f2d4
Reviewed-on: https://go-review.googlesource.com/1704
Reviewed-by: Andrew Gerrand <adg@golang.org>
This commit is contained in:
Andrew Gerrand 2014-12-17 15:49:59 +11:00
parent cf555faef7
commit 5bf57d6426

264
cmd/tipgodoc/tip.go Normal file
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// Copyright 2014 The Go AUTHORS. All rights reserved.
// Use of this source code is governed by the Apache 2.0
// license that can be found in the LICENSE file.
// Command tipgodoc is the beginning of the new tip.golang.org server,
// serving the latest HEAD straight from the Git oven.
package main
import (
"bufio"
"encoding/json"
"flag"
"fmt"
"io"
"io/ioutil"
"log"
"net/http"
"net/http/httputil"
"net/url"
"os"
"os/exec"
"path/filepath"
"sync"
"time"
)
const metaURL = "https://go.googlesource.com/?b=master&format=JSON"
var (
pollInterval = flag.Duration("poll", 10*time.Second, "Remote repo poll interval")
listenAddr = flag.String("listen", "localhost:8080", "HTTP listen address")
)
func main() {
flag.Parse()
p := new(Proxy)
go p.run()
http.Handle("/", p)
log.Fatal(http.ListenAndServe(*listenAddr, nil))
}
type Proxy struct {
mu sync.Mutex // owns the followin'
proxy *httputil.ReverseProxy
last string // signature of gorepo+toolsrepo
side string
}
// run runs in its own goroutine.
func (p *Proxy) run() {
p.side = "a"
for {
p.poll()
time.Sleep(*pollInterval)
}
}
// poll runs from the run loop goroutine.
func (p *Proxy) poll() {
heads := gerritMetaMap()
if heads == nil {
return
}
p.mu.Lock()
curSide := p.side
lastSig := p.last
p.mu.Unlock()
sig := heads["go"] + "-" + heads["tools"]
if sig == lastSig {
return
}
newSide := "b"
if curSide == "b" {
newSide = "a"
}
hostport, err := initSide(newSide, heads["go"], heads["tools"])
if err != nil {
log.Println(err)
return
}
p.mu.Lock()
defer p.mu.Unlock()
u, err := url.Parse(fmt.Sprintf("http://%v/", hostport))
if err != nil {
log.Println(err)
return
}
p.side = newSide
p.proxy = httputil.NewSingleHostReverseProxy(u)
p.last = sig
}
func initSide(side, goHash, toolsHash string) (hostport string, err error) {
dir := filepath.Join(os.TempDir(), "tipgodoc", side)
if err := os.MkdirAll(dir, 0755); err != nil {
return "", err
}
goDir := filepath.Join(dir, "go")
toolsDir := filepath.Join(dir, "gopath/src/golang.org/x/tools")
if err := checkout("https://go.googlesource.com/go", goHash, goDir); err != nil {
return "", err
}
if err := checkout("https://go.googlesource.com/tools", toolsHash, toolsDir); err != nil {
return "", err
}
env := []string{"GOROOT=" + goDir, "GOPATH=" + filepath.Join(dir, "gopath")}
make := exec.Command("./make.bash")
make.Stdout = os.Stdout
make.Stderr = os.Stderr
make.Dir = filepath.Join(goDir, "src")
if err := make.Run(); err != nil {
return "", err
}
goBin := filepath.Join(goDir, "bin/go")
install := exec.Command(goBin, "install", "golang.org/x/tools/cmd/godoc")
install.Stdout = os.Stdout
install.Stderr = os.Stderr
install.Env = env
if err := install.Run(); err != nil {
return "", err
}
godocBin := filepath.Join(goDir, "bin/godoc")
hostport = "localhost:8081"
if side == "b" {
hostport = "localhost:8082"
}
godoc := exec.Command(godocBin, "-http="+hostport)
godoc.Env = env
godoc.Stdout = os.Stdout
godoc.Stderr = os.Stderr
if err := godoc.Start(); err != nil {
return "", err
}
go func() {
// TODO(bradfitz): tell the proxy that this side is dead
if err := godoc.Wait(); err != nil {
log.Printf("side %v exited: %v", side, err)
}
}()
for i := 0; i < 15; i++ {
time.Sleep(time.Second)
var res *http.Response
res, err = http.Get(fmt.Sprintf("http://%v/", hostport))
if err != nil {
continue
}
res.Body.Close()
if res.StatusCode == http.StatusOK {
return hostport, nil
}
}
return "", fmt.Errorf("timed out waiting for side %v at %v (%v)", side, hostport, err)
}
func checkout(repo, hash, path string) error {
// Clone git repo if it doesn't exist.
if _, err := os.Stat(filepath.Join(path, ".git")); os.IsNotExist(err) {
if err := os.MkdirAll(filepath.Base(path), 0755); err != nil {
return err
}
cmd := exec.Command("git", "clone", repo, path)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
if err := cmd.Run(); err != nil {
// TODO(bradfitz): capture the standard error output
return err
}
} else if err != nil {
return err
}
cmd := exec.Command("git", "fetch")
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
cmd.Dir = path
if err := cmd.Run(); err != nil {
return err
}
cmd = exec.Command("git", "reset", "--hard", hash)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
cmd.Dir = path
if err := cmd.Run(); err != nil {
return err
}
cmd = exec.Command("git", "clean", "-d", "-f", "-x")
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
cmd.Dir = path
return cmd.Run()
}
func (p *Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if r.URL.Path == "/_tipstatus" {
p.serveStatus(w, r)
return
}
p.mu.Lock()
proxy := p.proxy
p.mu.Unlock()
if proxy == nil {
http.Error(w, "not ready", http.StatusInternalServerError)
return
}
proxy.ServeHTTP(w, r)
}
func (p *Proxy) serveStatus(w http.ResponseWriter, r *http.Request) {
p.mu.Lock()
defer p.mu.Unlock()
fmt.Fprintf(w, "side=%v\nlast=%v\n", p.side, p.last)
}
// gerritMetaMap returns the map from repo name (e.g. "go") to its
// latest master hash.
// The returned map is nil on any transient error.
func gerritMetaMap() map[string]string {
res, err := http.Get(metaURL)
if err != nil {
return nil
}
defer res.Body.Close()
defer io.Copy(ioutil.Discard, res.Body) // ensure EOF for keep-alive
if res.StatusCode != 200 {
return nil
}
var meta map[string]struct {
Branches map[string]string
}
br := bufio.NewReader(res.Body)
// For security reasons or something, this URL starts with ")]}'\n" before
// the JSON object. So ignore that.
// Shawn Pearce says it's guaranteed to always be just one line, ending in '\n'.
for {
b, err := br.ReadByte()
if err != nil {
return nil
}
if b == '\n' {
break
}
}
if err := json.NewDecoder(br).Decode(&meta); err != nil {
log.Printf("JSON decoding error from %v: %s", metaURL, err)
return nil
}
m := map[string]string{}
for repo, v := range meta {
if master, ok := v.Branches["master"]; ok {
m[repo] = master
}
}
return m
}