Refactor post requests, implement bot cancel/terminate

appengine/swarming/elements/res/imp/common/common-behavior.html

 <!--
   Copyright 2016 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.
 
   It contains the definition of the following Behaviors:
 
     SwarmingBehaviors.CommonBehavior
 
   To use it, include
@@ skipping 50 matching lines @@
       },
 
       _or: function() {
         var result = false;
         // can't use .foreach, as arguments isn't really an Array.
         for (var i = 0; i < arguments.length; i++) {
           result = result || arguments[i];
         }
         return result;
       },
+

[jcgregorio, 2016/09/02 18:31:22]

So there's already a similar solution that we have in sk.

sk common.js already is included here and includes the sk.errorMessage function:

  https://github.com/google/skia-buildbot/blob/master/res/js/common.js#L68

The only thing you're missing is an element to catch the errors, something like
error-toast-sk:

 
https://github.com/google/skia-buildbot/blob/master/res/imp/error-toast-sk.html

[kjlubick, 2016/09/06 13:06:31]

I considered using sk.errorMessage, but it doesn't allow me to keep the toast
open while the request is pending, which is something I want.

[jcgregorio, 2016/09/06 15:16:53]

I don't understand, why are you keeping it open?

[kjlubick, 2016/09/06 15:26:50]

It just feels like a better way to communicate with the user that something is
happening, that the request is pending.  If the toast closes after 10 seconds
(like error-toast-sk), it might be confusing to the user that the request is
still trying to go through.  Maybe not.

Maybe I can make my own version of error-toast-sk that takes an argument to
"stay open" or not.  What do you think?

[jcgregorio, 2016/09/06 15:33:32]

Yes, or add a parameter to error-toast-sk, either way would be fine.

+      // _postWithToast makes a post request and updates the provided paper-toast
+      // element with the response, regardless of failure.
+      _postWithToast: function(url, toast, auth_headers) {
+        // Keep toast displayed until we hear back from the request.
+        toast.duration = 0;
+        toast.open();
+        sk.request("POST", url, undefined, auth_headers).then(function(response) {
+          toast.close();
+          toast.show({
+            text: "Request sent.  Response: "+response,
+            duration: 3000,
+          });
+        }.bind(this)).catch(function(reason) {
+          console.log("Request failed", reason);
+          toast.close();
+          toast.show({
+            text: "Request failed.  Reason: "+reason,
+            duration: 3000,
+          });
+        }.bind(this));
+      }
     };
   })();
 </script>