WIP rendezvous hashing

config.js

@@ -1,4 +1,4 @@
-// Copyright (c) 2017 Uber Technologies, Inc.
+// Copyright (c) 2019 Uber Technologies, Inc.
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy
 // of this software and associated documentation files (the "Software"), to deal
@@ -23,6 +23,7 @@
 var _ = require('underscore');
 var EventEmitter = require('events').EventEmitter;
 var LoggingLevels = require('./lib/logging/levels.js');
+var HashingStrategies = require('./lib/hasher/hashing-strategies.js');
 var util = require('util');
 
 // This Config class is meant to be a central store
@@ -151,6 +152,11 @@ Config.prototype._seed = function _seed(seed) {
     // Ping a maximum ratio of the pingable members on self eviction
     seedOrDefault('selfEvictionMaxPingRatio', 0.4);
 
+    // Hashing strategy
+    // Use consistentHashing for backwards compatibility.
+    // Use rendezvousHashing for better ring distribution and light-weight bootstrap.
+    seedOrDefault('hashingStrategy', HashingStrategies.consistentHashing);
+
     function seedOrDefault(name, defaultVal, validator, reason) {
         var seedVal = seed[name];
         if (typeof seedVal === 'undefined') {

index.js

@@ -1,4 +1,4 @@
-// Copyright (c) 2017 Uber Technologies, Inc.
+// Copyright (c) 2019 Uber Technologies, Inc.
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy
 // of this software and associated documentation files (the "Software"), to deal
@@ -50,7 +50,9 @@ var Dissemination = require('./lib/gossip/dissemination.js');
 var discoverProviderFactory = require('./discover-providers.js');
 var errors = require('./lib/errors.js');
 var getTChannelVersion = require('./lib/util.js').getTChannelVersion;
-var HashRing = require('./lib/ring');
+var HashingStrategies = require('./lib/hasher/hashing-strategies');
+var HashRing = require('./lib/hasher/consistent-hashing');
+var RendezvousHasher = require('./lib/hasher/rendezvous-hashing');
 var initMembership = require('./lib/membership/index.js');
 var LoggerFactory = require('./lib/logging/logger_factory.js');
 var LagSampler = require('./lib/lag_sampler.js');
@@ -109,7 +111,6 @@ function RingPop(options) {
     }
     this.timers = options.timers || timers;
     this.setTimeout = options.setTimeout || timers.setTimeout;
-    this.Ring = options.Ring || HashRing;
 
     this.isReady = false;
 
@@ -154,6 +155,13 @@ function RingPop(options) {
         enforceKeyConsistency: options.enforceKeyConsistency
     });
 
+    this.Ring = options.Ring || HashRing;
+    if (this.config.get('hashingStrategy') === HashingStrategies.rendezvousHashing) {
+        this.Ring = RendezvousHasher;
+    }
+    // HACK (always use rendezvousHasher while testing)
+    this.Ring = RendezvousHasher;
+
     this.ring = new this.Ring({
         hashFunc: this.hashFunc
     });

lib/ring/index.js → lib/hasher/consistent-hashing/index.js

@@ -1,4 +1,4 @@
-// Copyright (c) 2017 Uber Technologies, Inc.
+// Copyright (c) 2019 Uber Technologies, Inc.
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy
 // of this software and associated documentation files (the "Software"), to deal
@@ -22,7 +22,7 @@ var EventEmitter = require('events').EventEmitter;
 var farmhash = require('farmhash');
 var util = require('util');
 var RBTree = require('./rbtree').RBTree;
-var RingEvents = require('./events.js');
+var RingEvents = require('../events.js');
 
 function HashRing(options) {
     this.options = options || {};

lib/ring/rbtree.js → lib/hasher/consistent-hashing/rbtree.js

@@ -1,4 +1,4 @@
-// Copyright (c) 2017 Uber Technologies, Inc.
+// Copyright (c) 2019 Uber Technologies, Inc.
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy
 // of this software and associated documentation files (the "Software"), to deal

lib/ring/events.js → lib/hasher/events.js

@@ -1,4 +1,4 @@
-// Copyright (c) 2017 Uber Technologies, Inc.
+// Copyright (c) 2019 Uber Technologies, Inc.
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy
 // of this software and associated documentation files (the "Software"), to deal

lib/hasher/hashing-strategies.js

@@ -0,0 +1,26 @@
+// Copyright (c) 2019 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+'use strict';
+
+module.exports = {
+    consistentHashing: 'consistent-hashing',
+    rendezvousHashing: 'rendezvous-hashing'
+};