server/web/middlewares/feature-toggles.js

   1 'use strict';
   2
   3 var fflip = require('fflip');
   4 var mongoUtils = require('gitter-web-persistence-utils/lib/mongo-utils');
   5 var persistence = require('gitter-web-persistence');
   6
   7 /**
   8  * List of criteria functions to be used by feature toggles
   9  */
  10 var Criteria = {
  11   /* Allow a certain percentage of users */
  12   percentageOfUsers: function(userDetails, percent) {
  13     var user = userDetails.user;
  14     if (!user) return false;
  15     var timestamp = Math.round(mongoUtils.getTimestampFromObjectId(user._id) / 1000) || 0;
  16     return timestamp % 100 < percent || undefined;
  17   },
  18
  19   /* Allow a hash of usernames */
  20   allowUsernames: function(userDetails, usernameHash) {
  21     var user = userDetails.user;
  22     if (!user) return false;
  23     if (!usernameHash) return undefined;
  24     return !!usernameHash[user.username] || undefined;
  25   },
  26
  27   disableBrowser: function(userDetails, browsers) {
  28     if (!browsers) return undefined;
  29
  30     var agent = userDetails.req.getParsedUserAgent();
  31
  32     var disabledVersion = browsers[agent.family];
  33     if (!disabledVersion) return undefined;
  34
  35     if (disabledVersion === 'all') return false;
  36     if (agent.major <= disabledVersion) return false;
  37     return undefined;
  38   },
  39
  40   bucket: function(userDetails, bucket) {
  41     var user = userDetails.user;
  42     if (!user) return false;
  43     var userId = user._id;
  44
  45     // This is copied from gitter-env.
  46     var lastChar = userId.toString().slice(-1);
  47     var userBucket = parseInt(lastChar + '', 16) % 2 ? 'A' : 'B';
  48
  49     return userBucket === bucket || undefined;
  50   },
  51
  52   createdAfter: function(userDetails, timestamp) {
  53     var user = userDetails.user;
  54     if (!user) return false;
  55     var userTimestamp = mongoUtils.getTimestampFromObjectId(user._id);
  56     return userTimestamp > timestamp || undefined;
  57   },
  58
  59   bucketCreatedAfter: function(userDetails, opts) {
  60     return (
  61       (Criteria.bucket(userDetails, opts.bucket) &&
  62         Criteria.createdAfter(userDetails, opts.createdAfter)) ||
  63       undefined
  64     );
  65   },
  66
  67   /* Enabled criteria */
  68   enabled: function(/*user*/) {
  69     return true;
  70   }
  71 };
  72
  73 function getFeatures(callback) {
  74   persistence.FeatureToggle.find({})
  75     .lean()
  76     .exec()
  77     .then(function(togglesList) {
  78       if (!togglesList || togglesList.length === 0) {
  79         return callback({});
  80       }
  81
  82       var featureToggles = togglesList.reduce(function(memo, toggle) {
  83         memo[toggle.name] = { criteria: toggle.criteria };
  84         return memo;
  85       }, {});
  86
  87       // NOTE: this callback doesn't have an err.
  88       callback(featureToggles);
  89     });
  90 }
  91
  92 fflip.config({
  93   criteria: Criteria,
  94   features: getFeatures,
  95   reload: 60, // Reload features every 60 seconds
  96   maxCookieAge: 31 * 86400 * 1000,
  97   useVetoVoting: true
  98 });
  99
 100 module.exports = [
 101   fflip.express_middleware,
 102   function(req, res, next) {
 103     // Only logged in users get features
 104     if (!req.user) return next();
 105
 106     req.fflip.setForUser({ user: req.user, req: req });
 107     next();
 108   }
 109 ];