Merge branch '24807-stop-ddosing-ourselves' into 'master'

Stop DDOSing ourselves

## What does this MR do?

Adds `hiddenInterval` to `SmartInterval` settings. This will be the interval used whilst the tab is inactive. If this setting is not set it will `cancel` as it would have done before.

Adds `immediateExecution` to `SmartInterval` settings. This boolean will dictate whether to execute the callback once before the first interval or not.

Uses `SmartInterval` with the new `hiddenInterval` settings to slow the polling for the MR widget on inactive tabs.

Fixes issue where `SmartInterval`s `visibilitychange` listeners are not getting called because jQuery doesn't support them.

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

We're ddosing ourselves on the MR page.

## Screenshots (if relevant)

![Screen_Shot_2016-11-25_at_18.36.25](/uploads/c4457c55872f592e921a50cf5462022e/Screen_Shot_2016-11-25_at_18.36.25.png)

~30 seconds difference between the first 2 requests _(a couple requests had fired already so it's backed off already)_.

_-changed to different tab-_

~2 minutes difference between the middle 2 requests.

_-changed tab back to MR-_

~10 seconds difference between the last 2 requests.

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?


Closes #24807

See merge request !7762

app/assets/javascripts/merge_request_widget.js.es6

@@ -40,19 +40,26 @@
       $('#modal_merge_info').modal({
         show: false
       });
-      this.firstCICheck = true;
-      this.readyForCICheck = false;
-      this.readyForCIEnvironmentCheck = false;
-      this.cancel = false;
-      clearInterval(this.fetchBuildStatusInterval);
-      clearInterval(this.fetchBuildEnvironmentStatusInterval);
       this.clearEventListeners();
       this.addEventListeners();
       this.getCIStatus(false);
-      this.getCIEnvironmentsStatus();
       this.retrieveSuccessIcon();
-      this.pollCIStatus();
-      this.pollCIEnvironmentsStatus();
+
+      this.ciStatusInterval = new global.SmartInterval({
+        callback: this.getCIStatus.bind(this, true),
+        startingInterval: 10000,
+        maxInterval: 30000,
+        hiddenInterval: 120000,
+        incrementByFactorOf: 5000,
+      });
+      this.ciEnvironmentStatusInterval = new global.SmartInterval({
+        callback: this.getCIEnvironmentsStatus.bind(this),
+        startingInterval: 30000,
+        maxInterval: 120000,
+        hiddenInterval: 240000,
+        incrementByFactorOf: 15000,
+        immediateExecution: true,
+      });
       notifyPermissions();
     }
 
@@ -60,10 +67,6 @@
       return $(document).off('page:change.merge_request');
     };
 
-    MergeRequestWidget.prototype.cancelPolling = function() {
-      return this.cancel = true;
-    };
-
     MergeRequestWidget.prototype.addEventListeners = function() {
       var allowedPages;
       allowedPages = ['show', 'commits', 'builds', 'pipelines', 'changes'];
@@ -72,9 +75,6 @@
           var page;
           page = $('body').data('page').split(':').last();
           if (allowedPages.indexOf(page) < 0) {
-            clearInterval(_this.fetchBuildStatusInterval);
-            clearInterval(_this.fetchBuildEnvironmentStatusInterval);
-            _this.cancelPolling();
             return _this.clearEventListeners();
           }
         };
@@ -114,6 +114,11 @@
       });
     };
 
+    MergeRequestWidget.prototype.cancelPolling = function () {
+      this.ciStatusInterval.cancel();
+      this.ciEnvironmentStatusInterval.cancel();
+    };
+
     MergeRequestWidget.prototype.getMergeStatus = function() {
       return $.get(this.opts.merge_check_url, function(data) {
         return $('.mr-state-widget').replaceWith(data);
@@ -131,18 +136,6 @@
       }
     };
 
-    MergeRequestWidget.prototype.pollCIStatus = function() {
-      return this.fetchBuildStatusInterval = setInterval(((function(_this) {
-        return function() {
-          if (!_this.readyForCICheck) {
-            return;
-          }
-          _this.getCIStatus(true);
-          return _this.readyForCICheck = false;
-        };
-      })(this)), 10000);
-    };
-
     MergeRequestWidget.prototype.getCIStatus = function(showNotification) {
       var _this;
       _this = this;
@@ -150,23 +143,17 @@
       return $.getJSON(this.opts.ci_status_url, (function(_this) {
         return function(data) {
           var message, status, title;
-          if (_this.cancel) {
-            return;
-          }
-          _this.readyForCICheck = true;
           if (data.status === '') {
             return;
           }
           if (data.environments && data.environments.length) _this.renderEnvironments(data.environments);
-          if (_this.firstCICheck || data.status !== _this.opts.ci_status && (data.status != null)) {
+          if (data.status !== _this.opts.ci_status && (data.status != null)) {
             _this.opts.ci_status = data.status;
             _this.showCIStatus(data.status);
             if (data.coverage) {
               _this.showCICoverage(data.coverage);
             }
-            // The first check should only update the UI, a notification
-            // should only be displayed on status changes
-            if (showNotification && !_this.firstCICheck) {
+            if (showNotification) {
               status = _this.ciLabelForStatus(data.status);
               if (status === "preparing") {
                 title = _this.opts.ci_title.preparing;
@@ -184,24 +171,13 @@
                 return Turbolinks.visit(_this.opts.builds_path);
               });
             }
-            return _this.firstCICheck = false;
           }
         };
       })(this));
     };
 
-    MergeRequestWidget.prototype.pollCIEnvironmentsStatus = function() {
-      this.fetchBuildEnvironmentStatusInterval = setInterval(() => {
-        if (!this.readyForCIEnvironmentCheck) return;
-        this.getCIEnvironmentsStatus();
-        this.readyForCIEnvironmentCheck = false;
-      }, 300000);
-    };
-
     MergeRequestWidget.prototype.getCIEnvironmentsStatus = function() {
       $.getJSON(this.opts.ci_environments_status_url, (environments) => {
-        if (this.cancel) return;
-        this.readyForCIEnvironmentCheck = true;
         if (environments && environments.length) this.renderEnvironments(environments);
       });
     };

app/assets/javascripts/smart_interval.js.es6

@@ -7,24 +7,31 @@
 (() => {
   class SmartInterval {
     /**
-      * @param { function } callback Function to be called on each iteration (required)
-      * @param { milliseconds } startingInterval `currentInterval` is set to this initially
-      * @param { milliseconds } maxInterval `currentInterval` will be incremented to this
-      * @param { integer } incrementByFactorOf `currentInterval` is incremented by this factor
-      * @param { boolean } lazyStart Configure if timer is initialized on instantiation or lazily
+      * @param { function } opts.callback Function to be called on each iteration (required)
+      * @param { milliseconds } opts.startingInterval `currentInterval` is set to this initially
+      * @param { milliseconds } opts.maxInterval `currentInterval` will be incremented to this
+      * @param { milliseconds } opts.hiddenInterval `currentInterval` is set to this
+      *                         when the page is hidden
+      * @param { integer } opts.incrementByFactorOf `currentInterval` is incremented by this factor
+      * @param { boolean } opts.lazyStart Configure if timer is initialized on
+      *                    instantiation or lazily
+      * @param { boolean } opts.immediateExecution Configure if callback should
+      *                    be executed before the first interval.
       */
-    constructor({ callback, startingInterval, maxInterval, incrementByFactorOf, lazyStart }) {
+    constructor(opts = {}) {
       this.cfg = {
-        callback,
-        startingInterval,
-        maxInterval,
-        incrementByFactorOf,
-        lazyStart,
+        callback: opts.callback,
+        startingInterval: opts.startingInterval,
+        maxInterval: opts.maxInterval,
+        hiddenInterval: opts.hiddenInterval,
+        incrementByFactorOf: opts.incrementByFactorOf,
+        lazyStart: opts.lazyStart,
+        immediateExecution: opts.immediateExecution,
       };
 
       this.state = {
         intervalId: null,
-        currentInterval: startingInterval,
+        currentInterval: this.cfg.startingInterval,
         pageVisibility: 'visible',
       };
 
@@ -36,6 +43,11 @@
       const cfg = this.cfg;
       const state = this.state;
 
+      if (cfg.immediateExecution) {
+        cfg.immediateExecution = false;
+        cfg.callback();
+      }
+
       state.intervalId = window.setInterval(() => {
         cfg.callback();
 
@@ -54,14 +66,29 @@
       this.stopTimer();
     }
 
+    onVisibilityHidden() {
+      if (this.cfg.hiddenInterval) {
+        this.setCurrentInterval(this.cfg.hiddenInterval);
+        this.resume();
+      } else {
+        this.cancel();
+      }
+    }
+
     // start a timer, using the existing interval
     resume() {
       this.stopTimer(); // stop exsiting timer, in case timer was not previously stopped
       this.start();
     }
 
+    onVisibilityVisible() {
+      this.cancel();
+      this.start();
+    }
+
     destroy() {
       this.cancel();
+      document.removeEventListener('visibilitychange', this.handleVisibilityChange);
       $(document).off('visibilitychange').off('page:before-unload');
     }
 
@@ -80,11 +107,7 @@
 
     initVisibilityChangeHandling() {
       // cancel interval when tab no longer shown (prevents cached pages from polling)
-      $(document)
-        .off('visibilitychange').on('visibilitychange', (e) => {
-          this.state.pageVisibility = e.target.visibilityState;
-          this.handleVisibilityChange();
-        });
+      document.addEventListener('visibilitychange', this.handleVisibilityChange.bind(this));
     }
 
     initPageUnloadHandling() {
@@ -92,10 +115,11 @@
       $(document).on('page:before-unload', () => this.cancel());
     }
 
-    handleVisibilityChange() {
-      const state = this.state;
-
-      const intervalAction = state.pageVisibility === 'hidden' ? this.cancel : this.resume;
+    handleVisibilityChange(e) {
+      this.state.pageVisibility = e.target.visibilityState;
+      const intervalAction = this.isPageVisible() ?
+        this.onVisibilityVisible :
+        this.onVisibilityHidden;
 
       intervalAction.apply(this);
     }
@@ -111,6 +135,7 @@
     incrementInterval() {
       const cfg = this.cfg;
       const currentInterval = this.getCurrentInterval();
+      if (cfg.hiddenInterval && !this.isPageVisible()) return;
       let nextInterval = currentInterval * cfg.incrementByFactorOf;
 
       if (nextInterval > cfg.maxInterval) {
@@ -120,6 +145,8 @@
       this.setCurrentInterval(nextInterval);
     }
 
+    isPageVisible() { return this.state.pageVisibility === 'visible'; }
+
     stopTimer() {
       const state = this.state;
 

changelogs/unreleased/24807-stop-ddosing-ourselves.yml

+---
+title: Use SmartInterval for MR widget and improve visibilitychange functionality
+merge_request: 7762
+author: 

spec/javascripts/smart_interval_spec.js.es6

@@ -14,8 +14,9 @@
       startingInterval: DEFAULT_STARTING_INTERVAL,
       maxInterval: DEFAULT_MAX_INTERVAL,
       incrementByFactorOf: DEFAULT_INCREMENT_FACTOR,
-      delayStartBy: 0,
       lazyStart: false,
+      immediateExecution: false,
+      hiddenInterval: null,
     };
 
     if (config) {
@@ -114,14 +115,31 @@
           expect(interval.state.intervalId).toBeTruthy();
 
           // simulates triggering of visibilitychange event
-          interval.state.pageVisibility = 'hidden';
-          interval.handleVisibilityChange();
+          interval.handleVisibilityChange({ target: { visibilityState: 'hidden' } });
 
           expect(interval.state.intervalId).toBeUndefined();
           done();
         }, DEFAULT_SHORT_TIMEOUT);
       });
 
+      it('should change to the hidden interval when page is not visible', function (done) {
+        const HIDDEN_INTERVAL = 1500;
+        const interval = createDefaultSmartInterval({ hiddenInterval: HIDDEN_INTERVAL });
+
+        setTimeout(() => {
+          expect(interval.state.intervalId).toBeTruthy();
+          expect(interval.getCurrentInterval() >= DEFAULT_STARTING_INTERVAL &&
+            interval.getCurrentInterval() <= DEFAULT_MAX_INTERVAL).toBeTruthy();
+
+          // simulates triggering of visibilitychange event
+          interval.handleVisibilityChange({ target: { visibilityState: 'hidden' } });
+
+          expect(interval.state.intervalId).toBeTruthy();
+          expect(interval.getCurrentInterval()).toBe(HIDDEN_INTERVAL);
+          done();
+        }, DEFAULT_SHORT_TIMEOUT);
+      });
+
       it('should resume when page is becomes visible at the previous interval', function (done) {
         const interval = this.smartInterval;
 
@@ -129,14 +147,12 @@
           expect(interval.state.intervalId).toBeTruthy();
 
           // simulates triggering of visibilitychange event
-          interval.state.pageVisibility = 'hidden';
-          interval.handleVisibilityChange();
+          interval.handleVisibilityChange({ target: { visibilityState: 'hidden' } });
 
           expect(interval.state.intervalId).toBeUndefined();
 
           // simulates triggering of visibilitychange event
-          interval.state.pageVisibility = 'visible';
-          interval.handleVisibilityChange();
+          interval.handleVisibilityChange({ target: { visibilityState: 'visible' } });
 
           expect(interval.state.intervalId).toBeTruthy();
 
@@ -154,6 +170,11 @@
           done();
         }, DEFAULT_SHORT_TIMEOUT);
       });
+
+      it('should execute callback before first interval', function () {
+        const interval = createDefaultSmartInterval({ immediateExecution: true });
+        expect(interval.cfg.immediateExecution).toBeFalsy();
+      });
     });
   });
 })(window.gl || (window.gl = {}));