cmd/tip: serve talks.golang.org

Also make health check test the backup process.

Change-Id: I9d2ed2780c07bb08683d231fccad4674c2ac22a1
Reviewed-on: https://go-review.googlesource.com/14668
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

cmd/tip/README

@@ -1,3 +1,7 @@
 To deploy tip.golang.org:
 
 $ gcloud --project golang-org preview app deploy --set-default godoc.yaml
+
+To deploy talks.golang.org:
+
+$ gcloud --project golang-org preview app deploy --set-default talks.yaml

cmd/tip/godoc.go

@@ -6,14 +6,11 @@ package main
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
-	"io/ioutil"
-	"log"
-	"net/http"
 	"os"
 	"os/exec"
 	"path/filepath"
-	"time"
 )
 
 type godocBuilder struct {
@@ -23,8 +20,6 @@ func (b godocBuilder) Signature(heads map[string]string) string {
 	return heads["go"] + "-" + heads["tools"]
 }
 
-var indexingMsg = []byte("Indexing in progress: result may be inaccurate")
-
 func (b godocBuilder) Init(dir, hostport string, heads map[string]string) (*exec.Cmd, error) {
 	goDir := filepath.Join(dir, "go")
 	toolsDir := filepath.Join(dir, "gopath/src/golang.org/x/tools")
@@ -60,29 +55,18 @@ func (b godocBuilder) Init(dir, hostport string, heads map[string]string) (*exec
 	if err := godoc.Start(); err != nil {
 		return nil, err
 	}
-	go func() {
-		// TODO(bradfitz): tell the proxy that this side is dead
-		if err := godoc.Wait(); err != nil {
-			log.Printf("process in %v exited: %v", dir, err)
-		}
-	}()
-
-	var err error
-	deadline := time.Now().Add(startTimeout)
-	for time.Now().Before(deadline) {
-		time.Sleep(time.Second)
-		var res *http.Response
-		res, err = http.Get(fmt.Sprintf("http://%v/search?q=FALLTHROUGH", hostport))
-		if err != nil {
-			continue
-		}
-		rbody, err := ioutil.ReadAll(res.Body)
-		res.Body.Close()
-		if err == nil && res.StatusCode == http.StatusOK &&
-			!bytes.Contains(rbody, indexingMsg) {
-			return godoc, nil
-		}
-	}
-	godoc.Process.Kill()
-	return nil, fmt.Errorf("timed out waiting for process in %v at %v (%v)", dir, hostport, err)
+	return godoc, nil
+}
+
+var indexingMsg = []byte("Indexing in progress: result may be inaccurate")
+
+func (b godocBuilder) HealthCheck(hostport string) error {
+	body, err := getOK(fmt.Sprintf("http://%v/search?q=FALLTHROUGH", hostport))
+	if err != nil {
+		return err
+	}
+	if bytes.Contains(body, indexingMsg) {
+		return errors.New("still indexing")
+	}
+	return nil
 }

cmd/tip/talks.go

@@ -0,0 +1,73 @@
+// Copyright 2015 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.
+
+package main
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+)
+
+type talksBuilder struct {
+}
+
+func (b talksBuilder) Signature(heads map[string]string) string {
+	return heads["talks"]
+}
+
+const talksToolsRev = "ac6d9c1d842f9b6482f39f7a172e0251a0f7cbc0"
+
+func (b talksBuilder) Init(dir, hostport string, heads map[string]string) (*exec.Cmd, error) {
+	toolsDir := filepath.Join(dir, "gopath/src/golang.org/x/tools")
+	if err := checkout(repoURL+"tools", talksToolsRev, toolsDir); err != nil {
+		return nil, err
+	}
+	talksDir := filepath.Join(dir, "gopath/src/golang.org/x/talks")
+	if err := checkout(repoURL+"talks", heads["talks"], talksDir); err != nil {
+		return nil, err
+	}
+
+	goDir := os.Getenv("GOROOT_BOOTSTRAP")
+	if goDir == "" {
+		goDir = runtime.GOROOT()
+	}
+	goBin := filepath.Join(goDir, "bin/go")
+	goPath := filepath.Join(dir, "gopath")
+	presentPath := "golang.org/x/tools/cmd/present"
+	install := exec.Command(goBin, "install", "-tags=appenginevm", presentPath)
+	install.Env = []string{"GOROOT=" + goDir, "GOPATH=" + goPath}
+	if err := runErr(install); err != nil {
+		return nil, err
+	}
+
+	talksBin := filepath.Join(goPath, "bin/present")
+	presentSrc := filepath.Join(goPath, "src", presentPath)
+	present := exec.Command(talksBin, "-http="+hostport, "-base="+presentSrc)
+	present.Dir = talksDir
+	// TODO(adg): log this somewhere useful
+	present.Stdout = os.Stdout
+	present.Stderr = os.Stderr
+	if err := present.Start(); err != nil {
+		return nil, err
+	}
+	return present, nil
+}
+
+var talksMsg = []byte("Talks - The Go Programming Language")
+
+func (b talksBuilder) HealthCheck(hostport string) error {
+	body, err := getOK(fmt.Sprintf("http://%v/", hostport))
+	if err != nil {
+		return err
+	}
+	if !bytes.Contains(body, talksMsg) {
+		return errors.New("couldn't match string")
+	}
+	return nil
+}

cmd/tip/talks.yaml

@@ -0,0 +1,15 @@
+module: talks
+runtime: custom
+api_version: go1
+vm: true
+
+automatic_scaling:
+  min_num_instances: 1
+  max_num_instances: 5
+
+handlers:
+- url: /.*
+  script: _go_app
+
+env_variables:
+  TIP_BUILDER: 'talks'

cmd/tip/tip.go

@@ -9,6 +9,7 @@ package main
 import (
 	"bufio"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -35,6 +36,8 @@ func main() {
 	switch os.Getenv(k) {
 	case "godoc":
 		b = godocBuilder{}
+	case "talks":
+		b = talksBuilder{}
 	default:
 		log.Fatalf("Unknown %v value: %q", k, os.Getenv(k))
 	}
@@ -54,17 +57,19 @@ func main() {
 type Proxy struct {
 	builder Builder
 
-	mu    sync.Mutex // protects the followin'
-	proxy http.Handler
-	cur   string    // signature of gorepo+toolsrepo
-	cmd   *exec.Cmd // live godoc instance, or nil for none
-	side  string
-	err   error
+	mu       sync.Mutex // protects the followin'
+	proxy    http.Handler
+	cur      string    // signature of gorepo+toolsrepo
+	cmd      *exec.Cmd // live godoc instance, or nil for none
+	side     string
+	hostport string // host and port of the live instance
+	err      error
 }
 
 type Builder interface {
 	Signature(heads map[string]string) string
 	Init(dir, hostport string, heads map[string]string) (*exec.Cmd, error)
+	HealthCheck(hostport string) error
 }
 
 func (p *Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
@@ -85,6 +90,10 @@ func (p *Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	if r.URL.Path == "/_ah/health" {
+		if err := p.builder.HealthCheck(p.hostport); err != nil {
+			http.Error(w, "Health check failde: "+err.Error(), http.StatusInternalServerError)
+			return
+		}
 		fmt.Fprintln(w, "OK")
 		return
 	}
@@ -148,6 +157,15 @@ func (p *Proxy) poll() {
 		hostport = "localhost:8082"
 	}
 	cmd, err := p.builder.Init(dir, hostport, heads)
+	if err == nil {
+		go func() {
+			// TODO(adg,bradfitz): be smarter about dead processes
+			if err := cmd.Wait(); err != nil {
+				log.Printf("process in %v exited: %v", dir, err)
+			}
+		}()
+		err = waitReady(p.builder, hostport)
+	}
 
 	p.mu.Lock()
 	defer p.mu.Unlock()
@@ -165,12 +183,25 @@ func (p *Proxy) poll() {
 	}
 	p.proxy = httputil.NewSingleHostReverseProxy(u)
 	p.side = newSide
+	p.hostport = hostport
 	if p.cmd != nil {
 		p.cmd.Process.Kill()
 	}
 	p.cmd = cmd
 }
 
+func waitReady(b Builder, hostport string) error {
+	var err error
+	deadline := time.Now().Add(startTimeout)
+	for time.Now().Before(deadline) {
+		if err = b.HealthCheck(hostport); err == nil {
+			return nil
+		}
+		time.Sleep(time.Second)
+	}
+	return fmt.Errorf("timed out waiting for process at %v: %v", hostport, err)
+}
+
 func runErr(cmd *exec.Cmd) error {
 	out, err := cmd.CombinedOutput()
 	if err != nil {
@@ -252,3 +283,19 @@ func gerritMetaMap() map[string]string {
 	}
 	return m
 }
+
+func getOK(url string) (body []byte, err error) {
+	res, err := http.Get(url)
+	if err != nil {
+		return nil, err
+	}
+	body, err = ioutil.ReadAll(res.Body)
+	res.Body.Close()
+	if err != nil {
+		return nil, err
+	}
+	if res.StatusCode != http.StatusOK {
+		return nil, errors.New(res.Status)
+	}
+	return body, nil
+}