Compare commits
1 Commits
| Author | SHA1 | Date |
|---|---|---|
 Vitaliy Filippov
|
a0b20be22c |
49
.eslintrc.js
49
.eslintrc.js
|
|
@ -1,49 +0,0 @@
|
|||
module.exports = {
|
||||
"env": {
|
||||
"es6": true,
|
||||
"node": true
|
||||
},
|
||||
"extends": [
|
||||
"eslint:recommended",
|
||||
"plugin:node/recommended"
|
||||
],
|
||||
"parserOptions": {
|
||||
"ecmaVersion": 2020
|
||||
},
|
||||
"plugins": [
|
||||
],
|
||||
"rules": {
|
||||
"indent": [
|
||||
"error",
|
||||
4
|
||||
],
|
||||
"brace-style": [
|
||||
"error",
|
||||
"allman",
|
||||
{ "allowSingleLine": true }
|
||||
],
|
||||
"linebreak-style": [
|
||||
"error",
|
||||
"unix"
|
||||
],
|
||||
"semi": [
|
||||
"error",
|
||||
"always"
|
||||
],
|
||||
"no-useless-escape": [
|
||||
"off"
|
||||
],
|
||||
"no-control-regex": [
|
||||
"off"
|
||||
],
|
||||
"no-empty": [
|
||||
"off"
|
||||
],
|
||||
"no-process-exit": [
|
||||
"off"
|
||||
],
|
||||
"node/shebang": [
|
||||
"off"
|
||||
]
|
||||
}
|
||||
};
|
||||
110
README.md
110
README.md
|
|
@ -1,110 +0,0 @@
|
|||
# TinyRaft
|
||||
|
||||
Raft leader election isolated from the rest of the algorithm.
|
||||
|
||||
TinyRaft doesn't know anything about replication and doesn't require you to
|
||||
implement it.
|
||||
|
||||
Actual network communication is also abstracted away and hidden behind a simple
|
||||
callback interface.
|
||||
|
||||
The only task of TinyRaft is to elect the leader and guarantee that there is
|
||||
only one leader at each moment.
|
||||
|
||||
TinyRaft can be used:
|
||||
- As a simple leader election algorithm without replication at all
|
||||
- As a building block for the standard Raft algorithm if you add log replication
|
||||
- For other variations of "weaker consensus" if you add another method of replication
|
||||
|
||||
Some replication ideas for you:
|
||||
- Log-less replication: Add a version number for each key in the database
|
||||
and make the leader synchronize follower databases by simply dumping all
|
||||
followers' databases with the newest term (followers with older terms should
|
||||
be ignored), comparing version numbers and making the newest version of each
|
||||
key win.
|
||||
- Erasure coding: Suppose you store large values. You can split each value into
|
||||
N parts, add K parity parts to it using Reed-Solomon codes (ISA-L/jerasure)
|
||||
and store them on different nodes in the form of Raft-like logs or similar
|
||||
to the log-less replication with version numbers, and make master synchronize
|
||||
followers by reconstructing every original value.
|
||||
|
||||
## Example Application
|
||||
|
||||
[AntiEtcd](https://git.yourcmc.ru/vitalif/antietcd/)
|
||||
|
||||
## Usage
|
||||
|
||||
```js
|
||||
const node = new TinyRaft({
|
||||
nodes: [ 1, 2, 3 ],
|
||||
nodeId: 1,
|
||||
electionTimeout: 5000,
|
||||
heartbeatTimeout: 1000,
|
||||
leadershipTimeout: 10000,
|
||||
initialTerm: 0,
|
||||
leaderPriority: 0,
|
||||
send: function(to, msg)
|
||||
{
|
||||
// Function to send message <msg> to node with ID <to>
|
||||
// msg.type is one of TinyRaft.VOTE_REQUEST, TinyRaft.VOTE, TinyRaft.PING, TinyRaft.PONG
|
||||
// msg.leader is the leader ID or null
|
||||
// msg.term is the term number
|
||||
// msg.priority is the optional leadership priority if set in config
|
||||
},
|
||||
});
|
||||
|
||||
// Watch for election state
|
||||
node.on('change', (st) =>
|
||||
{
|
||||
console.log(
|
||||
'node '+node.nodeId+': '+(st.state == TinyRaft.FOLLOWER ? 'following '+st.leader : st.state)+
|
||||
', term '+st.term+(st.state == TinyRaft.LEADER ? ', followers: '+st.followers.join(', ') : '')
|
||||
);
|
||||
});
|
||||
|
||||
// Start Raft node or start a new election round
|
||||
node.start();
|
||||
|
||||
// Optional; may be called for a follower when it receives a message from a live leader,
|
||||
// for example, a replication message, and causes the follower to move its round expiration forward
|
||||
node.markAlive();
|
||||
|
||||
// Update cluster node list
|
||||
node.setNodes([ 1, 2, 3 ]);
|
||||
|
||||
// Incoming messages should be fed to TinyRaft like this (from = ID of the sender):
|
||||
node.onReceive(from, msg);
|
||||
|
||||
// Stop Raft node
|
||||
node.stop();
|
||||
```
|
||||
|
||||
## Additional features
|
||||
|
||||
### Leader expiration
|
||||
|
||||
Supports leader expiration like in NuRaft:
|
||||
https://github.com/eBay/NuRaft/blob/master/docs/leadership_expiration.md
|
||||
|
||||
When leader expiration is enabled, followers respond to leader heartbeats
|
||||
(pings) with "pong" messages and if the leader doesn't receive a quorum of
|
||||
replies in leadershipTimeout - it starts a new round of voting.
|
||||
|
||||
### Leadership priorities
|
||||
|
||||
Also supports leader priorities, similar to NuRaft but even simpler:
|
||||
if a node receives a VoteRequest message with larger term but with smaller
|
||||
priority than its own, it immediately starts a new voting round.
|
||||
|
||||
It guarantees that a node with non-maximum priority can't become leader
|
||||
without being re-elected.
|
||||
|
||||
If all priorities are equal (or just zero), the election algorithm
|
||||
becomes identical to the basic algorithm without priorities.
|
||||
|
||||
# Author and License
|
||||
|
||||
Author: Vitaliy Filippov, 2024
|
||||
|
||||
License: [Mozilla Public License 2.0](https://www.mozilla.org/media/MPL/2.0/index.f75d2927d3c1.txt)
|
||||
or [Vitastor Network Public License 1.1](https://git.yourcmc.ru/vitalif/vitastor/src/branch/master/VNPL-1.1.txt)
|
||||
44
faketimer.js
44
faketimer.js
|
|
@ -1,44 +0,0 @@
|
|||
// Fake timer for node.js which _guarantees_ that all asynchronous timer
|
||||
// callbacks are called during a tested period
|
||||
|
||||
function FakeTimer(startTime)
|
||||
{
|
||||
this.time = Number(startTime)||0;
|
||||
this.timers = [];
|
||||
this.id = 0;
|
||||
this.setTimeout = (func, ms) =>
|
||||
{
|
||||
this.timers.push({ id: ++this.id, func, at: this.time+ms });
|
||||
return this.id;
|
||||
};
|
||||
this.setInterval = (func, ms) =>
|
||||
{
|
||||
this.timers.push({ id: ++this.id, func, at: this.time+ms, repeat: ms });
|
||||
return this.id;
|
||||
};
|
||||
this.clearInterval = this.clearTimeout = (id) =>
|
||||
{
|
||||
this.timers = this.timers.filter(t => t.id != id);
|
||||
};
|
||||
this.setImmediate = (func) => this.setTimeout(func, 0);
|
||||
this.runFor = (ms) =>
|
||||
{
|
||||
const end = this.time+ms;
|
||||
this.timers.sort((a, b) => a.at - b.at);
|
||||
while (this.timers.length && this.timers[0].at <= end)
|
||||
{
|
||||
const { func, at, repeat } = this.timers[0];
|
||||
if (!repeat)
|
||||
this.timers.shift();
|
||||
else
|
||||
this.timers[0].at += repeat;
|
||||
if (at > this.time)
|
||||
this.time = at;
|
||||
func();
|
||||
this.timers.sort((a, b) => a.at - b.at);
|
||||
}
|
||||
this.time = end;
|
||||
};
|
||||
}
|
||||
|
||||
module.exports = FakeTimer;
|
||||
35
package.json
35
package.json
|
|
@ -1,35 +0,0 @@
|
|||
{
|
||||
"name": "tinyraft",
|
||||
"version": "1.0.1",
|
||||
"description": "Tiny & abstract Raft leader election algorithm",
|
||||
"main": "tinyraft.js",
|
||||
"scripts": {
|
||||
"lint": "eslint tinyraft.js tinyraft.spec.js faketimer.js",
|
||||
"test": "node tinyraft.spec.js"
|
||||
},
|
||||
"repository": {
|
||||
"type": "git",
|
||||
"url": "https://git.yourcmc.ru/vitalif/tinyraft"
|
||||
},
|
||||
"homepage": "https://git.yourcmc.ru/vitalif/tinyraft",
|
||||
"bugs": {
|
||||
"url": "https://git.yourcmc.ru/vitalif/tinyraft/issues"
|
||||
},
|
||||
"files": [
|
||||
"tinyraft.js",
|
||||
"tinyraft.d.ts",
|
||||
"README.md"
|
||||
],
|
||||
"keywords": [
|
||||
"raft"
|
||||
],
|
||||
"author": "Vitaliy Filippov",
|
||||
"license": "MPL-2.0",
|
||||
"engines": {
|
||||
"node": ">=12.0.0"
|
||||
},
|
||||
"devDependencies": {
|
||||
"eslint": "^8.0.0",
|
||||
"eslint-plugin-node": "^11.1.0"
|
||||
}
|
||||
}
|
||||
|
|
@ -1,36 +0,0 @@
|
|||
import type { EventEmitter } from 'events';
|
||||
|
||||
export type TinyRaftEvents = {
|
||||
change: {
|
||||
state: 'LEADER'|'FOLLOWER'|'CANDIDATE',
|
||||
term: number,
|
||||
leader: string|number,
|
||||
followers: (string|number)[],
|
||||
}[],
|
||||
};
|
||||
|
||||
export type RaftMessage = {
|
||||
type: 'VOTE_REQUEST'|'VOTE'|'PING'|'PONG',
|
||||
term: number,
|
||||
leader?: string|number,
|
||||
priority?: number,
|
||||
};
|
||||
|
||||
export class TinyRaft extends EventEmitter<TinyRaftEvents>
|
||||
{
|
||||
constructor(cfg: {
|
||||
nodes: (number|string)[],
|
||||
nodeId: number|string,
|
||||
electionTimeout?: number,
|
||||
heartbeatTimeout?: number,
|
||||
leadershipTimeout?: number,
|
||||
initialTerm?: number,
|
||||
leaderPriority?: number,
|
||||
send: (to: number|string, msg: RaftMessage) => void,
|
||||
});
|
||||
start();
|
||||
stop();
|
||||
onReceive(from: number|string, msg: RaftMessage);
|
||||
markAlive();
|
||||
setNodes(nodes: (number|string)[]);
|
||||
}
|
||||
205
tinyraft.js
205
tinyraft.js
|
|
@ -9,20 +9,9 @@
|
|||
// The only requirement is to guarantee preservation of entries confirmed by
|
||||
// all hosts participating in consensus.
|
||||
//
|
||||
// Supports leader expiration like in NuRaft:
|
||||
// Supports pre-vote protocol and leader expiration like in NuRaft:
|
||||
// https://github.com/eBay/NuRaft/blob/master/docs/prevote_protocol.md
|
||||
// https://github.com/eBay/NuRaft/blob/master/docs/leadership_expiration.md
|
||||
//
|
||||
// Also supports leader priorities, similar to NuRaft but even simpler:
|
||||
// If a node receives a VoteRequest message with larger term but with smaller
|
||||
// priority than its own, it immediately starts a new voting round.
|
||||
// It guarantees that a node with non-maximum priority can't become leader
|
||||
// without being re-elected.
|
||||
// If all priorities are equal (or just zero), the election algorithm
|
||||
// becomes identical to the basic algorithm without priorities.
|
||||
//
|
||||
// (c) Vitaliy Filippov, 2024
|
||||
// License: Mozilla Public License 2.0 or Vitastor Network Public License 1.1
|
||||
// (https://git.yourcmc.ru/vitalif/vitastor/src/branch/master/VNPL-1.1.txt)
|
||||
|
||||
const EventEmitter = require('events');
|
||||
|
||||
|
|
@ -30,6 +19,10 @@ const VOTE_REQUEST = 'vote_request';
|
|||
const VOTE = 'vote';
|
||||
const PING = 'ping';
|
||||
const PONG = 'pong';
|
||||
// Following 3 are required only for the "pre-vote" feature
|
||||
const PRE_VOTE_REQUEST = 'pre_vote_request';
|
||||
const PRE_VOTE = 'pre_vote';
|
||||
const FOLLOW = 'follow';
|
||||
|
||||
const CANDIDATE = 'candidate';
|
||||
const LEADER = 'leader';
|
||||
|
|
@ -43,11 +36,9 @@ class TinyRaft extends EventEmitter
|
|||
// electionTimeout?: number,
|
||||
// heartbeatTimeout?: number,
|
||||
// leadershipTimeout?: number,
|
||||
// enablePrevote?: bool,
|
||||
// initialTerm?: number,
|
||||
// leaderPriority?: number,
|
||||
// }
|
||||
// NOTE: leadershipTimeout, if enabled, should be > heartbeatTimeout, and ideally < electionTimeout
|
||||
// In that case a leader with dead network will be expired before being re-elected
|
||||
constructor(config)
|
||||
{
|
||||
super();
|
||||
|
|
@ -58,7 +49,7 @@ class TinyRaft extends EventEmitter
|
|||
this.randomTimeout = config.randomTimeout > 0 ? Number(config.randomTimeout) : this.electionTimeout;
|
||||
this.heartbeatTimeout = Number(config.heartbeatTimeout) || 1000;
|
||||
this.leadershipTimeout = Number(config.leadershipTimeout) || 0;
|
||||
this.leaderPriority = Number(config.leaderPriority) || undefined;
|
||||
this.enablePrevote = config.enablePrevote ? true : false;
|
||||
if (!this.nodeId || this.nodeId instanceof Object ||
|
||||
!(this.nodes instanceof Array) || this.nodes.filter(n => !n || n instanceof Object).length > 0 ||
|
||||
!(this.send instanceof Function))
|
||||
|
|
@ -68,42 +59,63 @@ class TinyRaft extends EventEmitter
|
|||
this.term = 0;
|
||||
this.state = null;
|
||||
this.leader = null;
|
||||
this.confirmed = {};
|
||||
this.preVoting = false;
|
||||
}
|
||||
|
||||
_nextTerm(after)
|
||||
{
|
||||
if (this.electionTimer)
|
||||
{
|
||||
TinyRaft.clearTimeout(this.electionTimer);
|
||||
clearTimeout(this.electionTimer);
|
||||
this.electionTimer = null;
|
||||
}
|
||||
if (after >= 0)
|
||||
{
|
||||
this.electionTimer = TinyRaft.setTimeout(() => this.start(), after + this.randomTimeout * Math.random());
|
||||
this.electionTimer = setTimeout(() => this.start(), after + this.randomTimeout * Math.random());
|
||||
}
|
||||
}
|
||||
|
||||
_prevote()
|
||||
{
|
||||
this.leaderTimedOut = true;
|
||||
this.preVoting = true;
|
||||
this.preVoteOk = this.preVoteFail = 0;
|
||||
this.votes = { [this.nodeId]: [ this.nodeId ] };
|
||||
for (const node of this.nodes)
|
||||
{
|
||||
if (node != this.nodeId)
|
||||
{
|
||||
this.send(node, { type: PRE_VOTE_REQUEST, term: this.term });
|
||||
}
|
||||
}
|
||||
this._nextTerm(this.electionTimeout);
|
||||
}
|
||||
|
||||
start()
|
||||
{
|
||||
this._nextTerm(-1);
|
||||
this.electionTimer = null;
|
||||
if (this.enablePrevote && !this.preVoting)
|
||||
{
|
||||
this._prevote();
|
||||
return;
|
||||
}
|
||||
this.preVoting = false;
|
||||
this.term++;
|
||||
this.voted = 1;
|
||||
this.votes = { [this.nodeId]: [ this.nodeId ] };
|
||||
this.state = CANDIDATE;
|
||||
this.followers = null;
|
||||
this.confirmed = {};
|
||||
this.leader = this.nodeId;
|
||||
if (!this.heartbeatTimer)
|
||||
{
|
||||
this.heartbeatTimer = TinyRaft.setInterval(() => this._heartbeat(), this.heartbeatTimeout);
|
||||
this.heartbeatTimer = setInterval(() => this._heartbeat(), this.heartbeatTimeout);
|
||||
}
|
||||
for (const node of this.nodes)
|
||||
{
|
||||
if (node != this.nodeId)
|
||||
{
|
||||
this.send(node, { type: VOTE_REQUEST, term: this.term, leader: this.leader, priority: this.leaderPriority });
|
||||
this.send(node, { type: VOTE_REQUEST, term: this.term, leader: this.leader });
|
||||
}
|
||||
}
|
||||
// Next term will start right after this one times out
|
||||
|
|
@ -115,12 +127,12 @@ class TinyRaft extends EventEmitter
|
|||
{
|
||||
if (this.electionTimer)
|
||||
{
|
||||
TinyRaft.clearTimeout(this.electionTimer);
|
||||
clearTimeout(this.electionTimer);
|
||||
this.electionTimer = null;
|
||||
}
|
||||
if (this.heartbeatTimer)
|
||||
{
|
||||
TinyRaft.clearInterval(this.heartbeatTimer);
|
||||
clearTimeout(this.heartbeatTimer);
|
||||
this.heartbeatTimer = null;
|
||||
}
|
||||
}
|
||||
|
|
@ -129,12 +141,11 @@ class TinyRaft extends EventEmitter
|
|||
{
|
||||
if (this.state == LEADER)
|
||||
{
|
||||
this.confirmed = {};
|
||||
for (const node of (this.leadershipTimeout ? this.followers : this.nodes))
|
||||
for (const node of this.votes[this.nodeId])
|
||||
{
|
||||
if (node != this.nodeId)
|
||||
{
|
||||
this.send(node, { type: PING, term: this.term, priority: this.leaderPriority });
|
||||
this.send(node, { type: PING, term: this.term });
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
@ -142,83 +153,52 @@ class TinyRaft extends EventEmitter
|
|||
|
||||
onReceive(from, msg)
|
||||
{
|
||||
if (msg.type == VOTE_REQUEST)
|
||||
if (msg.type == PRE_VOTE_REQUEST)
|
||||
{
|
||||
this._onReceiveVoteRequest(from, msg);
|
||||
this.send(from, { type: PRE_VOTE, term: this.term, leader: this.leaderTimedOut ? null : this.leader });
|
||||
}
|
||||
else if (msg.type == VOTE)
|
||||
else if (msg.type == PRE_VOTE && this.preVoting)
|
||||
{
|
||||
this._onReceiveVote(from, msg);
|
||||
}
|
||||
else if (msg.type == PING)
|
||||
if (msg.term == this.term && msg.leader)
|
||||
{
|
||||
this._onReceivePing(from, msg);
|
||||
}
|
||||
else if (msg.type == PONG)
|
||||
{
|
||||
this._onReceivePong(from, msg);
|
||||
}
|
||||
}
|
||||
|
||||
_onReceiveVoteRequest(from, msg)
|
||||
{
|
||||
if (msg.term > this.term && msg.leader)
|
||||
{
|
||||
if (this.leaderPriority && (msg.priority||0) < this.leaderPriority)
|
||||
{
|
||||
this.term = msg.term;
|
||||
this.start();
|
||||
this.preVoteOk++;
|
||||
}
|
||||
else
|
||||
{
|
||||
this.preVoteFail++;
|
||||
}
|
||||
if (this.preVoteOk > this.nodes.length/2)
|
||||
{
|
||||
this.preVoting = false;
|
||||
this.preVoteOk = 0;
|
||||
this.preVoteFail = 0;
|
||||
this._nextTerm(this.electionTimeout);
|
||||
}
|
||||
if (this.preVoteFail > this.nodes.length/2)
|
||||
{
|
||||
this._nextTerm(-1);
|
||||
this.preVoteOk = 0;
|
||||
this.preVoteFail = 0;
|
||||
this.start();
|
||||
}
|
||||
}
|
||||
else if (msg.type == VOTE_REQUEST)
|
||||
{
|
||||
if (msg.term > this.term && msg.leader)
|
||||
{
|
||||
this.leader = msg.leader;
|
||||
this.term = msg.term;
|
||||
this.state = CANDIDATE;
|
||||
this.followers = null;
|
||||
this.confirmed = {};
|
||||
this._nextTerm(this.heartbeatTimeout*2 + this.electionTimeout);
|
||||
this.emit('change', { state: this.state, term: this.term, leader: this.leader });
|
||||
}
|
||||
this.send(from, { type: VOTE, term: this.term, leader: this.leader });
|
||||
}
|
||||
const prio = (this.leader == this.nodeId ? this.leaderPriority : undefined);
|
||||
this.send(from, { type: VOTE, term: this.term, leader: this.leader, priority: prio });
|
||||
}
|
||||
|
||||
_onReceiveVote(from, msg)
|
||||
{
|
||||
if (!msg.leader || msg.term < this.term)
|
||||
{
|
||||
return;
|
||||
}
|
||||
if (msg.term > this.term)
|
||||
{
|
||||
this.term = msg.term;
|
||||
this.state = FOLLOWER;
|
||||
this.followers = null;
|
||||
this.confirmed = {};
|
||||
this.leader = msg.leader;
|
||||
this.votes = {};
|
||||
this.emit('change', { state: this.state, term: this.term, leader: this.leader });
|
||||
// Repeat VOTE to the leader to join it
|
||||
this.send(this.leader, { type: VOTE, term: this.term, leader: this.leader, priority: msg.priority });
|
||||
return;
|
||||
}
|
||||
// add <from> as voter for <msg.leader>
|
||||
this.votes[msg.leader] = this.votes[msg.leader] || [];
|
||||
let found = false;
|
||||
for (const voter of this.votes[msg.leader])
|
||||
{
|
||||
if (voter == from)
|
||||
{
|
||||
found = true;
|
||||
break;
|
||||
}
|
||||
}
|
||||
if (!found)
|
||||
else if (msg.type == VOTE && msg.term == this.term)
|
||||
{
|
||||
this.voted++;
|
||||
this.votes[msg.leader] = this.votes[msg.leader] || [];
|
||||
this.votes[msg.leader].push(from);
|
||||
}
|
||||
const n = this.votes[msg.leader].length;
|
||||
if (n == 1 + (0 | this.nodes.length/2))
|
||||
{
|
||||
|
|
@ -226,11 +206,16 @@ class TinyRaft extends EventEmitter
|
|||
{
|
||||
this.leader = msg.leader;
|
||||
this.state = LEADER;
|
||||
this.confirmed = {};
|
||||
this._nextTerm(this.leadershipTimeout > 0 ? this.leadershipTimeout : -1);
|
||||
this.followers = this.votes[this.nodeId];
|
||||
for (const follower of this.followers)
|
||||
{
|
||||
if (follower != this.nodeId)
|
||||
{
|
||||
// Send a heartbeat to confirm leadership
|
||||
this._heartbeat();
|
||||
this.send(follower, { type: PING, term: this.term });
|
||||
}
|
||||
}
|
||||
this.emit('change', { state: this.state, term: this.term, leader: this.nodeId, followers: this.votes[this.nodeId] });
|
||||
}
|
||||
else
|
||||
|
|
@ -242,7 +227,7 @@ class TinyRaft extends EventEmitter
|
|||
{
|
||||
this.followers = this.votes[this.nodeId];
|
||||
// Send a heartbeat to confirm leadership
|
||||
this.send(from, { type: PING, term: this.term, priority: this.leaderPriority });
|
||||
this.send(from, { type: PING, term: this.term });
|
||||
this.emit('change', { state: this.state, term: this.term, leader: this.nodeId, followers: this.votes[this.nodeId] });
|
||||
}
|
||||
else if (this._isVotingFailed())
|
||||
|
|
@ -250,47 +235,35 @@ class TinyRaft extends EventEmitter
|
|||
this._nextTerm(0);
|
||||
}
|
||||
}
|
||||
|
||||
_onReceivePing(from, msg)
|
||||
else if (msg.type == PING)
|
||||
{
|
||||
if (this.state == CANDIDATE && this.term == msg.term && from == this.leader)
|
||||
{
|
||||
this.state = FOLLOWER;
|
||||
this.emit('change', { state: this.state, term: this.term, leader: this.leader });
|
||||
this.emit('change', { state: this.state, term: this.term, leader: this.nodeId });
|
||||
}
|
||||
if (this.state == FOLLOWER && from == this.leader)
|
||||
{
|
||||
this.markAlive();
|
||||
}
|
||||
if (this.leadershipTimeout > 0 || this.state == FOLLOWER && from != this.leader)
|
||||
if (this.leadershipTimeout > 0)
|
||||
{
|
||||
this.send(from, { type: PONG, term: this.term, leader: this.leader });
|
||||
}
|
||||
}
|
||||
|
||||
_onReceivePong(from, msg)
|
||||
else if (msg.type == PONG && this.state == LEADER)
|
||||
{
|
||||
if (this.state != LEADER)
|
||||
{
|
||||
return;
|
||||
}
|
||||
if (msg.leader != this.nodeId || msg.term != this.term)
|
||||
this._nextTerm(-1);
|
||||
if (msg.leader != this.nodeId)
|
||||
{
|
||||
this.start();
|
||||
}
|
||||
else if (this.leadershipTimeout > 0)
|
||||
{
|
||||
this.confirmed[from] = true;
|
||||
if (Object.keys(this.confirmed).length >= (1 + (0 | this.nodes.length/2)))
|
||||
{
|
||||
// We have quorum
|
||||
this._nextTerm(this.leadershipTimeout);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
markAlive()
|
||||
{
|
||||
this.leaderTimedOut = false;
|
||||
this._nextTerm(this.heartbeatTimeout*2 + this.electionTimeout);
|
||||
}
|
||||
|
||||
|
|
@ -316,22 +289,18 @@ class TinyRaft extends EventEmitter
|
|||
if (this.state == LEADER)
|
||||
{
|
||||
this.votes[this.nodeId] = this.votes[this.nodeId].filter(n => nodes.indexOf(n) >= 0);
|
||||
if (this.votes[this.nodeId].length < (1 + (0 | this.nodes.length/2)))
|
||||
this.start();
|
||||
else
|
||||
this.emit('change', { state: this.state, term: this.term, leader: this.nodeId, followers: this.votes[this.nodeId] });
|
||||
}
|
||||
else if (this.state == FOLLOWER && nodes.indexOf(this.leader) < 0 || this.state == CANDIDATE)
|
||||
{
|
||||
this.start();
|
||||
r.nextTerm(-1);
|
||||
r.start();
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
TinyRaft.setTimeout = setTimeout;
|
||||
TinyRaft.clearTimeout = clearTimeout;
|
||||
TinyRaft.setInterval = setInterval;
|
||||
TinyRaft.clearInterval = clearInterval;
|
||||
TinyRaft.PRE_VOTE_REQUEST = PRE_VOTE_REQUEST;
|
||||
TinyRaft.PRE_VOTE = PRE_VOTE;
|
||||
TinyRaft.VOTE_REQUEST = VOTE_REQUEST;
|
||||
TinyRaft.VOTE = VOTE;
|
||||
TinyRaft.PING = PING;
|
||||
|
|
|
|||
275
tinyraft.spec.js
275
tinyraft.spec.js
|
|
@ -1,51 +1,39 @@
|
|||
const TinyRaft = require('./tinyraft.js');
|
||||
const FakeTimer = require('./faketimer.js');
|
||||
|
||||
const fake = new FakeTimer();
|
||||
TinyRaft.setTimeout = fake.setTimeout;
|
||||
TinyRaft.clearTimeout = fake.clearTimeout;
|
||||
TinyRaft.setInterval = fake.setInterval;
|
||||
TinyRaft.clearInterval = fake.clearInterval;
|
||||
|
||||
function newNode(id, nodes, partitions, mod)
|
||||
function newNode(id, nodes, partitions)
|
||||
{
|
||||
partitions = partitions || {};
|
||||
let cfg = {
|
||||
let n = new TinyRaft({
|
||||
nodes: [ 1, 2, 3, 4, 5 ],
|
||||
nodeId: id,
|
||||
heartbeatTimeout: 100,
|
||||
electionTimeout: 500,
|
||||
send: function(to, msg)
|
||||
{
|
||||
if (!partitions[n.nodeId+'-'+to] && !partitions[to+'-'+n.nodeId] && nodes[to])
|
||||
if (!partitions[n.nodeId+'-'+to] && nodes[to])
|
||||
{
|
||||
console.log('['+fake.time+'] received from '+n.nodeId+' to '+to+': '+JSON.stringify(msg));
|
||||
fake.setImmediate(function() { nodes[to].onReceive(n.nodeId, msg); });
|
||||
console.log('received from '+n.nodeId+' to '+to+': '+JSON.stringify(msg));
|
||||
setImmediate(function() { nodes[to].onReceive(n.nodeId, msg); });
|
||||
}
|
||||
else
|
||||
console.log('['+fake.time+'] failed to send from '+n.nodeId+' to '+to+': '+JSON.stringify(msg));
|
||||
},
|
||||
};
|
||||
if (mod)
|
||||
mod(cfg);
|
||||
let n = new TinyRaft(cfg);
|
||||
});
|
||||
n.on('change', (st) =>
|
||||
{
|
||||
console.log(
|
||||
'['+fake.time+'] node '+n.nodeId+': '+(st.state == TinyRaft.FOLLOWER ? 'following '+st.leader : st.state)+
|
||||
'node '+n.nodeId+': '+(st.state == TinyRaft.FOLLOWER ? 'following '+st.leader : st.state)+
|
||||
', term '+st.term+(st.state == TinyRaft.LEADER ? ', followers: '+st.followers.join(', ') : '')
|
||||
);
|
||||
});
|
||||
nodes[id] = n;
|
||||
}
|
||||
|
||||
function newNodes(count, partitions, mod)
|
||||
function newNodes(count, partitions)
|
||||
{
|
||||
partitions = partitions || {};
|
||||
const nodes = {};
|
||||
for (let i = 1; i <= count; i++)
|
||||
{
|
||||
newNode(i, nodes, partitions, mod);
|
||||
newNode(i, nodes, partitions);
|
||||
}
|
||||
for (let i = 1; i <= count; i++)
|
||||
{
|
||||
|
|
@ -57,7 +45,6 @@ function newNodes(count, partitions, mod)
|
|||
function checkQuorum(nodes, count)
|
||||
{
|
||||
let leaders = 0;
|
||||
let out = 0;
|
||||
for (const i in nodes)
|
||||
{
|
||||
if (nodes[i].state == TinyRaft.LEADER)
|
||||
|
|
@ -68,8 +55,6 @@ function checkQuorum(nodes, count)
|
|||
}
|
||||
else if (nodes[i].state != TinyRaft.FOLLOWER)
|
||||
{
|
||||
out++;
|
||||
if (out > nodes.length-count)
|
||||
throw new Error('node '+i+' is not in quorum: state '+nodes[i].state);
|
||||
}
|
||||
}
|
||||
|
|
@ -77,7 +62,7 @@ function checkQuorum(nodes, count)
|
|||
{
|
||||
throw new Error('we have '+leaders+' leaders instead of exactly 1');
|
||||
}
|
||||
console.log('['+fake.time+'] OK: '+count+' nodes in quorum');
|
||||
console.log('OK: '+count+' nodes in quorum');
|
||||
}
|
||||
|
||||
function checkNoQuorum(nodes)
|
||||
|
|
@ -87,12 +72,11 @@ function checkNoQuorum(nodes)
|
|||
{
|
||||
throw new Error('we have non-candidates ('+nc.map(n => n.nodeId).join(', ')+'), but we should not');
|
||||
}
|
||||
console.log('['+fake.time+'] OK: '+Object.keys(nodes).length+' candidates, no quorum');
|
||||
console.log('OK: '+Object.keys(nodes).length+' candidates, no quorum');
|
||||
}
|
||||
|
||||
async function testStartThenRemoveNode()
|
||||
{
|
||||
console.log('--------------------------------------------------------------------------------');
|
||||
console.log('testStartThenRemoveNode');
|
||||
const nodes = newNodes(5);
|
||||
let leaderChanges = 0, prevLeader = null;
|
||||
|
|
@ -104,7 +88,7 @@ async function testStartThenRemoveNode()
|
|||
leaderChanges++;
|
||||
}
|
||||
});
|
||||
fake.runFor(2000);
|
||||
await new Promise(ok => setTimeout(ok, 2000));
|
||||
checkQuorum(nodes, 5);
|
||||
if (leaderChanges >= 3)
|
||||
{
|
||||
|
|
@ -116,7 +100,7 @@ async function testStartThenRemoveNode()
|
|||
nodes[leader].stop();
|
||||
delete nodes[leader];
|
||||
// Check quorum after 2000ms
|
||||
fake.runFor(2000);
|
||||
await new Promise(ok => setTimeout(ok, 2000));
|
||||
checkQuorum(nodes, 4);
|
||||
// Stop the leader again
|
||||
leader = nodes[Object.keys(nodes)[0]].leader;
|
||||
|
|
@ -124,7 +108,7 @@ async function testStartThenRemoveNode()
|
|||
nodes[leader].stop();
|
||||
delete nodes[leader];
|
||||
// Check quorum after 2000ms
|
||||
fake.runFor(2000);
|
||||
await new Promise(ok => setTimeout(ok, 2000));
|
||||
checkQuorum(nodes, 3);
|
||||
// Stop the leader again
|
||||
leader = nodes[Object.keys(nodes)[0]].leader;
|
||||
|
|
@ -132,7 +116,7 @@ async function testStartThenRemoveNode()
|
|||
nodes[leader].stop();
|
||||
delete nodes[leader];
|
||||
// Check that no quorum exists
|
||||
fake.runFor(2000);
|
||||
await new Promise(ok => setTimeout(ok, 2000));
|
||||
checkNoQuorum(nodes);
|
||||
// Clean up
|
||||
for (const id in nodes)
|
||||
|
|
@ -144,10 +128,9 @@ async function testStartThenRemoveNode()
|
|||
|
||||
async function testAddNode()
|
||||
{
|
||||
console.log('--------------------------------------------------------------------------------');
|
||||
console.log('testAddNode');
|
||||
const nodes = newNodes(5, {}, cfg => cfg.initialTerm = 1000);
|
||||
fake.runFor(2000);
|
||||
const nodes = newNodes(5);
|
||||
await new Promise(ok => setTimeout(ok, 2000));
|
||||
checkQuorum(nodes, 5);
|
||||
// Add node
|
||||
newNode(6, nodes);
|
||||
|
|
@ -155,7 +138,7 @@ async function testAddNode()
|
|||
nodes[i].setNodes([ 1, 2, 3, 4, 5, 6 ]);
|
||||
nodes[6].start();
|
||||
// Check quorum after 2000ms
|
||||
fake.runFor(2000);
|
||||
await new Promise(ok => setTimeout(ok, 2000));
|
||||
checkQuorum(nodes, 6);
|
||||
// Clean up
|
||||
for (const id in nodes)
|
||||
|
|
@ -165,200 +148,62 @@ async function testAddNode()
|
|||
console.log('testAddNode: OK');
|
||||
}
|
||||
|
||||
async function testLeadershipExpiration()
|
||||
async function testPreVote()
|
||||
{
|
||||
console.log('--------------------------------------------------------------------------------');
|
||||
console.log('testLeadershipExpiration');
|
||||
const partitions = {};
|
||||
const nodes = newNodes(5, partitions, cfg => cfg.leadershipTimeout = 1500);
|
||||
// Check that 5 nodes are in quorum after 2000ms
|
||||
fake.runFor(2000);
|
||||
checkQuorum(nodes, 5);
|
||||
// Break network on the leader
|
||||
let leader = nodes[1].leader;
|
||||
console.log("["+fake.time+"] --> stopping the leader's ("+leader+") network");
|
||||
for (let i = 1; i <= 5; i++)
|
||||
// The original example for pre-vote protocol from here:
|
||||
// https://github.com/eBay/NuRaft/blob/master/docs/prevote_protocol.md
|
||||
// only has partitions between nodes 1-5, 2-4, 3-4.
|
||||
// But that setup has a problem of leader jumping between nodes 3 and 4
|
||||
// which can't be prevented by prevotes because 4 only has connections
|
||||
// to 2 nodes so they can't form a majority to reject the vote.
|
||||
const partitions = {
|
||||
'1-5': true,
|
||||
'2-4': true,
|
||||
'3-4': true,
|
||||
'2-3': true,
|
||||
'5-1': true,
|
||||
'4-2': true,
|
||||
'4-3': true,
|
||||
'3-2': true,
|
||||
};
|
||||
const nodes = newNodes(5, partitions);
|
||||
let leader = await new Promise((ok, no) =>
|
||||
{
|
||||
partitions[i+'-'+leader] = true;
|
||||
partitions[leader+'-'+i] = true;
|
||||
}
|
||||
// Check that the leader loses leadership after 2 * leadershipTimeout
|
||||
fake.runFor(3000);
|
||||
if (nodes[leader].state != TinyRaft.CANDIDATE)
|
||||
{
|
||||
throw new Error("leadership expiration doesn't work");
|
||||
}
|
||||
// Clean up
|
||||
for (const id in nodes)
|
||||
{
|
||||
nodes[id].stop();
|
||||
}
|
||||
console.log('testLeadershipExpiration: OK');
|
||||
}
|
||||
|
||||
async function testRestart()
|
||||
{
|
||||
console.log('--------------------------------------------------------------------------------');
|
||||
console.log('testRestart');
|
||||
const nodes = newNodes(5, {}, cfg => cfg.initialTerm = 1000);
|
||||
let leaderChanges = 0, prevLeader = null;
|
||||
nodes[2].on('change', (st) =>
|
||||
{
|
||||
const leader = st.state == TinyRaft.CANDIDATE ? null : st.leader;
|
||||
if (leader != prevLeader)
|
||||
{
|
||||
prevLeader = leader;
|
||||
leaderChanges++;
|
||||
setTimeout(() => no(new Error('no leader in 500 ms')), 500);
|
||||
const chg = (st) =>
|
||||
{
|
||||
if (st.leader)
|
||||
{
|
||||
nodes[1].off('change', chg);
|
||||
if (st.leader != 1 && st.leader != 5)
|
||||
no('leader is not 1 or 5');
|
||||
ok(st.leader);
|
||||
}
|
||||
};
|
||||
nodes[1].on('change', chg);
|
||||
});
|
||||
// Check that 5 nodes are in quorum after 2000ms
|
||||
fake.runFor(2000);
|
||||
checkQuorum(nodes, 5);
|
||||
if (leaderChanges >= 3)
|
||||
console.log('OK: Got leader in 500 ms');
|
||||
await new Promise((ok, no) =>
|
||||
{
|
||||
throw new Error("leaderChanges = "+leaderChanges+" (expected < 3)");
|
||||
}
|
||||
// Stop a follower
|
||||
let restarted = 1 + (prevLeader % 5);
|
||||
if (restarted == 2)
|
||||
setTimeout(ok, 5000);
|
||||
const chg = (st) =>
|
||||
{
|
||||
restarted = 1 + (prevLeader + 1) % 5;
|
||||
}
|
||||
console.log("["+fake.time+"] --> stopping a follower (node "+restarted+")");
|
||||
nodes[restarted].stop();
|
||||
delete nodes[restarted];
|
||||
// Wait 2000ms
|
||||
fake.runFor(2000);
|
||||
// Restart a follower
|
||||
console.log("["+fake.time+"] --> restarting a follower (node "+restarted+")");
|
||||
leaderChanges = 0;
|
||||
newNode(restarted, nodes, {}, null);
|
||||
nodes[restarted].start();
|
||||
// Check quorum and the fact that the leader didn't change after 2000ms
|
||||
fake.runFor(2000);
|
||||
checkQuorum(nodes, 5);
|
||||
if (leaderChanges > 0)
|
||||
if (st.state != TinyRaft.FOLLOWER || st.leader != leader)
|
||||
{
|
||||
throw new Error("leader changed after restart of a follower");
|
||||
nodes[5].off('change', chg);
|
||||
no(new Error('leader changed in 5000 ms'));
|
||||
}
|
||||
// Clean up
|
||||
for (const id in nodes)
|
||||
{
|
||||
nodes[id].stop();
|
||||
}
|
||||
console.log('testRestart: OK');
|
||||
}
|
||||
|
||||
async function testChangeNodes()
|
||||
{
|
||||
console.log('--------------------------------------------------------------------------------');
|
||||
console.log('testChangeNodes');
|
||||
console.log('['+fake.time+'] --> starting nodes 1-5');
|
||||
const nodes = newNodes(5, {}, cfg => cfg.initialTerm = 1000);
|
||||
// Check that 5 nodes are in quorum after 2000ms
|
||||
fake.runFor(2000);
|
||||
checkQuorum(nodes, 5);
|
||||
// Stop node 4
|
||||
console.log('['+fake.time+'] --> stopping node 4');
|
||||
nodes[4].stop();
|
||||
delete nodes[4];
|
||||
// Wait 1000ms
|
||||
fake.runFor(1000);
|
||||
// Change nodes from 1 2 3 4 5 to 1 2 3 5 6
|
||||
console.log('['+fake.time+'] --> starting node 6');
|
||||
newNode(6, nodes);
|
||||
nodes[6].start();
|
||||
nodes[1].setNodes([ 1, 2, 3, 5, 6 ]);
|
||||
nodes[2].setNodes([ 1, 2, 3, 5, 6 ]);
|
||||
nodes[3].setNodes([ 1, 2, 3, 5, 6 ]);
|
||||
nodes[5].setNodes([ 1, 2, 3, 5, 6 ]);
|
||||
nodes[6].setNodes([ 1, 2, 3, 5, 6 ]);
|
||||
// Check that 5 nodes are in quorum after 2000ms
|
||||
fake.runFor(2000);
|
||||
checkQuorum(nodes, 5);
|
||||
// Clean up
|
||||
for (const id in nodes)
|
||||
{
|
||||
if (nodes[id])
|
||||
nodes[id].stop();
|
||||
}
|
||||
console.log('testChangeNodes: OK');
|
||||
}
|
||||
|
||||
async function testLeaderPriority()
|
||||
{
|
||||
console.log('--------------------------------------------------------------------------------');
|
||||
console.log('testLeaderPriority');
|
||||
console.log('['+fake.time+'] --> starting nodes 1-5');
|
||||
const nodes = newNodes(5, {}, cfg => cfg.leaderPriority = cfg.nodeId+1);
|
||||
// Check that 5 nodes are in quorum after 2000ms
|
||||
fake.runFor(2000);
|
||||
checkQuorum(nodes, 5);
|
||||
if (nodes[1].leader != 5)
|
||||
{
|
||||
throw new Error('leader is not 5');
|
||||
}
|
||||
// Stop node 5
|
||||
console.log('['+fake.time+'] --> stopping node 5');
|
||||
nodes[5].stop();
|
||||
delete nodes[5];
|
||||
// Wait 2000ms and check that the leader is now 4
|
||||
fake.runFor(2000);
|
||||
checkQuorum(nodes, 4);
|
||||
if (nodes[1].leader != 4)
|
||||
{
|
||||
throw new Error('leader is not 4');
|
||||
}
|
||||
// Stop node 4
|
||||
console.log('['+fake.time+'] --> stopping node 4');
|
||||
nodes[4].stop();
|
||||
delete nodes[4];
|
||||
// Wait 2000ms and check that the leader is now 3
|
||||
fake.runFor(2000);
|
||||
checkQuorum(nodes, 3);
|
||||
if (nodes[1].leader != 3)
|
||||
{
|
||||
throw new Error('leader is not 3');
|
||||
}
|
||||
// Clean up
|
||||
for (const id in nodes)
|
||||
{
|
||||
if (nodes[id])
|
||||
nodes[id].stop();
|
||||
}
|
||||
console.log('testLeaderPriority: OK');
|
||||
}
|
||||
|
||||
async function testPartition1_3()
|
||||
{
|
||||
console.log('--------------------------------------------------------------------------------');
|
||||
console.log('testPartition1_3');
|
||||
const partitions = { '1-3': true, '3-1': true };
|
||||
const nodes = newNodes(3, partitions, cfg => cfg.nodes = [ 1, 2, 3 ]);
|
||||
// Check that 2 or 3 nodes are in quorum after 5000ms
|
||||
// This situation should be fixed by "prevote protocol", but it breaks other things
|
||||
fake.runFor(5000);
|
||||
if (nodes[2].leader == 2)
|
||||
checkQuorum(nodes, 3);
|
||||
else
|
||||
checkQuorum(nodes, 2);
|
||||
// Clean up
|
||||
for (const id in nodes)
|
||||
{
|
||||
nodes[id].stop();
|
||||
}
|
||||
console.log('testPartition1_3: OK');
|
||||
};
|
||||
nodes[5].on('change', chg);
|
||||
});
|
||||
console.log('OK: No leader change in 5000 ms');
|
||||
}
|
||||
|
||||
async function run()
|
||||
{
|
||||
await testStartThenRemoveNode();
|
||||
await testAddNode();
|
||||
await testLeadershipExpiration();
|
||||
await testRestart();
|
||||
await testChangeNodes();
|
||||
await testLeaderPriority();
|
||||
await testPartition1_3();
|
||||
await testPreVote();
|
||||
process.exit(0);
|
||||
}
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue