[ui/courier] batch fetch requests for all searches and docs

src/core_plugins/kibana/public/dashboard/panel/load_saved_object.js

@@ -10,7 +10,6 @@ export function loadSavedObject(loaders, panel) {
   if (!loader) {
     throw new Error(`No loader for object of type ${panel.type}`);
   }
-  const isDefered = true;
-  return loader.get(panel.id, isDefered)
+  return loader.get(panel.id)
     .then(savedObj => ({ savedObj, editUrl: loader.urlFor(panel.id) }));
 }

src/ui/public/courier/fetch/fetch.js

@@ -8,23 +8,32 @@ import ReqStatusProvider from './req_status';
 export default function fetchService(Private, Promise) {
 
   const requestQueue = Private(RequestQueueProvider);
-  const fetchThese = Private(FetchTheseProvider);
-
+  const immediatelyFetchThese = Private(FetchTheseProvider);
   const callResponseHandlers = Private(CallResponseHandlersProvider);
   const INCOMPLETE = Private(ReqStatusProvider).INCOMPLETE;
 
-  function fetchQueued(strategy) {
-    const requests = requestQueue.getStartable(strategy);
-    if (!requests.length) return Promise.resolve();
-    else return fetchThese(requests);
-  }
+  const debouncedFetchThese = _.debounce(() => {
+    const requests = requestQueue.get().filter(req => req.isFetchRequested());
+    immediatelyFetchThese(requests);
+  }, {
+    wait: 10,
+    maxWait: 50
+  });
 
-  this.fetchQueued = fetchQueued;
+  const fetchTheseSoon = (requests) => {
+    requests.forEach(req => req._setFetchRequested());
+    debouncedFetchThese();
+    return Promise.all(requests.map(req => req.defer.promise));
+  };
+
+  this.fetchQueued = (strategy) => {
+    return fetchTheseSoon(requestQueue.getStartable(strategy));
+  };
 
   function fetchASource(source, strategy) {
     const defer = Promise.defer();
 
-    fetchThese([
+    fetchTheseSoon([
       source._createRequest(defer)
     ]);
 
@@ -50,7 +59,7 @@ export default function fetchService(Private, Promise) {
    * @param {array} reqs - the requests to fetch
    * @async
    */
-  this.these = fetchThese;
+  this.these = fetchTheseSoon;
 
   /**
    * Send responses to a list of requests, used when requests

src/ui/public/courier/fetch/request/request.js

@@ -15,12 +15,42 @@ export default function AbstractReqProvider(Private, Promise) {
       this.source = source;
       this.defer = defer || Promise.defer();
       this._whenAbortedHandlers = [];
-
       requestQueue.push(this);
     }
 
+    /**
+     *  Called by the loopers to find requests that should be sent to the
+     *  fetch() module. When a module is sent to fetch() it's _fetchRequested flag
+     *  is set, and this consults that flag so requests are not send to fetch()
+     *  multiple times.
+     *
+     *  @return {Boolean}
+     */
     canStart() {
-      return Boolean(!this.stopped && !this.source._fetchDisabled);
+      return !this._fetchRequested && !this.stopped && !this.source._fetchDisabled;
+    }
+
+    /**
+     *  Used to find requests that were previously sent to the fetch() module but
+     *  have not been started yet, so they can be started.
+     *
+     *  @return {Boolean}
+     */
+    isFetchRequestedAndPending() {
+      return !!this._fetchRequested && !this.started;
+    }
+
+    /**
+     *  Called by the fetch() module when this request has been sent to
+     *  be fetched. At that point the request is somewhere between `ready-to-start`
+     *  and `started`. The fetch module then waits a short period of time to
+     *  allow requests to build up in the request queue, and then immediately
+     *  fetches all requests that return true from `isFetchRequested()`
+     *
+     *  @return {undefined}
+     */
+    _setFetchRequested() {
+      this._fetchRequested = true;
     }
 
     start() {

src/ui/public/courier/saved_object/saved_object.js

@@ -127,7 +127,7 @@ export default function SavedObjectFactory(esAdmin, kbnIndex, Promise, Private,
      * @return {Promise}
      * @resolved {SavedObject}
      */
-    this.init = _.once((isDefered) => {
+    this.init = _.once(() => {
       // ensure that the type is defined
       if (!type) throw new Error('You must define a type name to use SavedObject objects.');
 
@@ -166,13 +166,7 @@ export default function SavedObjectFactory(esAdmin, kbnIndex, Promise, Private,
           }
 
           // fetch the object from ES
-          if (isDefered) {
-            const defer = Promise.defer();
-            docSource._createRequest(defer);
-            return defer.promise.then(this.applyESResp);
-          } else {
-            return docSource.fetch().then(this.applyESResp);
-          }
+          return docSource.fetch().then(this.applyESResp);
         })
         .then(() => {
           return customInit.call(this);

src/ui/public/courier/saved_object/saved_object_loader.js

@@ -29,8 +29,8 @@ export class SavedObjectLoader {
    * @param id
    * @returns {Promise<SavedObject>}
    */
-  get(id, isDefered) {
-    return (new this.Class(id)).init(isDefered);
+  get(id) {
+    return (new this.Class(id)).init();
   }
 
   urlFor(id) {