playground: increase urlfetch timeout on GAE classic

The default timeout for urlfetch requests on App Engine Classic is
5 seconds. Sometimes the requests can take longer, so increase it to
the maximum value of 60 seconds. The playground has its own timeout for
running code so there's no need to impose a second level of protection.

Also cleans up the code to remove old appenginevm code and use the
correct imports.

Change-Id: I15da96e5ba70fb008bf821f4609f431847662223
Reviewed-on: https://go-review.googlesource.com/129395
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Andrew Bonventre <andybons@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

playground/appengine.go

@@ -7,20 +7,28 @@
 package playground
 
 import (
+	"context"
+	"io"
 	"net/http"
 
-	"appengine"
-	"appengine/urlfetch"
+	"google.golang.org/appengine"
+	"google.golang.org/appengine/log"
+	"google.golang.org/appengine/urlfetch"
 )
 
 func init() {
 	onAppengine = !appengine.IsDevAppServer()
 }
 
-func client(r *http.Request) *http.Client {
-	return urlfetch.Client(appengine.NewContext(r))
+func contextFunc(r *http.Request) context.Context {
+	return appengine.NewContext(r)
+}
+
+func post(ctx context.Context, url, contentType string, body io.Reader) (*http.Response, error) {
+	return urlfetch.Client(ctx).Post(url, contentType, body)
 }
 
 func report(r *http.Request, err error) {
-	appengine.NewContext(r).Errorf("%v", err)
+	ctx := appengine.NewContext(r)
+	log.Errorf(ctx, "%v", err)
 }

playground/common.go

@@ -9,10 +9,12 @@ package playground // import "golang.org/x/tools/playground"
 
 import (
 	"bytes"
+	"context"
 	"errors"
 	"fmt"
 	"io"
 	"net/http"
+	"time"
 )
 
 const baseURL = "https://golang.org"
@@ -25,7 +27,7 @@ func init() {
 func bounce(w http.ResponseWriter, r *http.Request) {
 	b := new(bytes.Buffer)
 	if err := passThru(b, r); err != nil {
-		http.Error(w, "Server error.", http.StatusInternalServerError)
+		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
 		report(r, err)
 		return
 	}
@@ -38,7 +40,9 @@ func passThru(w io.Writer, req *http.Request) error {
 	}
 	defer req.Body.Close()
 	url := baseURL + req.URL.Path
-	r, err := client(req).Post(url, req.Header.Get("Content-type"), req.Body)
+	ctx, cancel := context.WithTimeout(contextFunc(req), 60*time.Second)
+	defer cancel()
+	r, err := post(ctx, url, req.Header.Get("Content-type"), req.Body)
 	if err != nil {
 		return fmt.Errorf("making POST request: %v", err)
 	}
@@ -49,7 +53,7 @@ func passThru(w io.Writer, req *http.Request) error {
 	return nil
 }
 
-var onAppengine = false // will be overridden by appengine.go and appenginevm.go
+var onAppengine = false // will be overridden by appengine.go
 
 func allowShare(r *http.Request) bool {
 	if !onAppengine {

playground/local.go

@@ -7,12 +7,23 @@
 package playground
 
 import (
+	"context"
+	"fmt"
+	"io"
 	"log"
 	"net/http"
 )
 
-func client(r *http.Request) *http.Client {
-	return http.DefaultClient
+func post(ctx context.Context, url, contentType string, body io.Reader) (*http.Response, error) {
+	req, err := http.NewRequest("POST", url, body)
+	if err != nil {
+		return nil, fmt.Errorf("http.NewRequest: %v", err)
+	}
+	return http.DefaultClient.Do(req.WithContext(ctx))
+}
+
+func contextFunc(_ *http.Request) context.Context {
+	return context.Background()
 }
 
 func report(r *http.Request, err error) {