Adds checking of template error

go/src/infra/tricium/service/default/handlers.go

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Package handlers implements HTTP handlers for the default module.
 package handlers
 
 import (
         "html/template"
         "net/http"
 
         "google.golang.org/appengine"
         "google.golang.org/appengine/taskqueue"
 )
 
 func init() {
         http.HandleFunc("/", landingPageHandler)
         http.HandleFunc("/analyze", analyzeHandler)
 }
 
 var basePage = template.Must(template.ParseFiles("templates/base.html"))
 
 func landingPageHandler(w http.ResponseWriter, r *http.Request) {
         data := map[string]interface{}{
                 "Msg":             "This service is under construction ...",
                 "ShowRequestForm": true,
         }
-        basePage.Execute(w, data)
+        if e := basePage.Execute(w, data); e != nil {

[nodir, 2016/07/14 16:33:00]

I recommend calling the variable "err" because it is pretty standard across all
Go code I saw

[emso, 2016/07/15 11:04:43]

Done.

+                http.Error(w, e.Error(), http.StatusInternalServerError)

[nodir, 2016/07/14 16:33:00]

the error description is sent to the user and not logged. If this happens, it
will be hard for you to analyze the error because you won't know what was the
error.
I'd log it. Also consider sending "Internal server error, we are working on it"
or something like that to the user, so you don't expose implementation details
to the user.

Also consider writing a helper function that executes a template to response, so
you don't have to copy this code everywhere

[emso, 2016/07/15 11:04:43]

Done.

+                return
+        }
 }
 
 func analyzeHandler(w http.ResponseWriter, r *http.Request) {
         ctx := appengine.NewContext(r)
         t := taskqueue.NewPOSTTask("/workflow-launcher/queue-handler", map[string][]string{"name": {"Analyze Request"}})
         if _, err := taskqueue.Add(ctx, t, "workflow-launcher-queue"); err != nil {
                 http.Error(w, err.Error(), http.StatusInternalServerError)
                 return
         }
         data := map[string]interface{}{
                 "Msg": "Dummy analysis request sent.",
         }
-        basePage.Execute(w, data)
+        if e := basePage.Execute(w, data); e != nil {
+                http.Error(w, e.Error(), http.StatusInternalServerError)
+                return
+        }
 }