Milo: Prefetch logs that are failures

milo/appengine/swarming/html.go

 // Copyright 2015 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 package swarming
 
 import (
         "net/http"
         "os"
 
@@ skipping 68 matching lines @@
 func (b Build) Render(c context.Context, r *http.Request, p httprouter.Params) (*templates.Args, error) {
         // Get the swarming ID
         id := p.ByName("id")
         if id == "" {
                 return nil, &miloerror.Error{
                         Message: "No id",
                         Code:    http.StatusBadRequest,
                 }
         }
 
-        result, err := swarmingBuildImpl(c, r.URL.String(), getServer(r), id)
+        result, prefetch, err := swarmingBuildImpl(c, r.URL.String(), getServer(r), id)
         if err != nil {
                 return nil, convertErr(err)
         }
 
         // Render into the template
         args := &templates.Args{
-                "Build": result,
+                "Build":    result,
+                "Prefetch": prefetch,
         }
         return args, nil
 }
 
 func convertErr(err error) error {
         if isAPINotFound(err) || os.IsNotExist(err) {
                 return &miloerror.Error{
                         Message: err.Error(),
                         Code:    http.StatusNotFound,
                 }
         }
         return err
 }
 
 // isAPINotFound returns true if err is a HTTP 404 API response.
 func isAPINotFound(err error) bool {
         if apiErr, ok := err.(*googleapi.Error); ok && apiErr.Code == http.StatusNotFound {
                 return true
         }
 
         return false
 }