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No need to poll #71

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No need to poll #71

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33124ba
feat: no need to poll
richardschneider Feb 2, 2018
18b7918
docs: broadcast defaults to true
richardschneider Feb 2, 2018
8f5d4e4
test: faster tests with smaller RSA key
richardschneider Feb 2, 2018
4cae8fa
test: linting
richardschneider Feb 2, 2018
8d057c9
fix: racey stop
richardschneider Feb 5, 2018
9dec015
fix: lint
richardschneider Feb 5, 2018
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8 changes: 4 additions & 4 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -22,12 +22,12 @@ const mdns = new MDNS(peerInfo, options)
mdns.on('peer', (peerInfo) => {
console.log('Found a peer in the local network', peerInfo.id.toB58String())
})
process.on('exit', mdns.stop)

// Broadcast for 20 seconds
mdns.start(() => setTimeout(() => mdns.stop(() => {}), 20 * 1000))
// Listen for peers
mdns.start()
```

- options
- `broadcast` - (true/false) announce our presence through mDNS, default false
- `interval` - query interval, default 10 * 1000 (10 seconds)
- `broadcast` - (true/false) announce our presence through mDNS, default true
- `serviceTag` - name of the service announcedm, default 'ipfs.local`
29 changes: 15 additions & 14 deletions src/index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -12,11 +12,9 @@ class MulticastDNS extends EventEmitter {
options = options || {}

this.broadcast = options.broadcast !== false
this.interval = options.interval || (1e3 * 10)
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@richardschneider instead of removing the feature all together, it should support for a single beacon.

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Not really sure why you want a beacon?

interval controlled how often an MDNS query is sent. Every time it is sent, all other IPFS nodes must respond with their DNS records.

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@diasdavid any comments?

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I do not see a need to drop the interval beacon feature. The module should support both, single beacon and interval.

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First off, a beacon is not what MDNS is about. Secondly it can be very expensive.

Consider a data centre with 100 servers all running IPFS with an interval of 10 minutes, or 600 seconds. On average, a node will beacon every 6 seconds. Then every 6 seconds all other nodes must wake-up and reply with their DNS records. All nodes will then see all the nodes responses and have to then .emit discovered nodes. It's a real waste of network bandwidth and CPU.

this.serviceTag = options.serviceTag || 'ipfs.local'
this.port = options.port || 5353
this.peerInfo = peerInfo
this._queryInterval = null
}

start (callback) {
Expand All @@ -25,10 +23,11 @@ class MulticastDNS extends EventEmitter {

this.mdns = mdns

this._queryInterval = query.queryLAN(this.mdns, this.serviceTag, this.interval)

mdns.on('response', (event) => {
query.gotResponse(event, this.peerInfo, this.serviceTag, (err, foundPeer) => {
if (!self.mdns) {
return
}
query.gotResponse(event, self.peerInfo, self.serviceTag, (err, foundPeer) => {
if (err) {
return log('Error processing peer response', err)
}
Expand All @@ -38,21 +37,23 @@ class MulticastDNS extends EventEmitter {
})

mdns.on('query', (event) => {
query.gotQuery(event, this.mdns, this.peerInfo, this.serviceTag, this.broadcast)
if (!self.mdns) {
return
}
query.gotQuery(event, self.mdns, self.peerInfo, self.serviceTag, self.broadcast)
})

setImmediate(() => callback())
query.queryLAN(this.mdns, this.serviceTag)
setImmediate(callback)
}

stop (callback) {
if (!this.mdns) {
callback(new Error('MulticastDNS service had not started yet'))
} else {
clearInterval(this._queryInterval)
this._queryInterval = null
this.mdns.destroy(callback)
this.mdns = undefined
const mdns = this.mdns
if (!mdns) {
return callback(new Error('MulticastDNS service had not started yet'))
}
this.mdns = undefined
mdns.destroy(callback)
}
}

Expand Down
20 changes: 7 additions & 13 deletions src/query.js
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Original file line number Diff line number Diff line change
Expand Up @@ -12,19 +12,13 @@ const tcp = new TCP()
module.exports = {

queryLAN: function (mdns, serviceTag, interval) {
const query = () => {
log('query', serviceTag)
mdns.query({
questions: [{
name: serviceTag,
type: 'PTR'
}]
})
}

// Immediately start a query, then do it every interval.
query()
return setInterval(query, interval)
log('query', serviceTag)
mdns.query({
questions: [{
name: serviceTag,
type: 'PTR'
}]
})
},

gotResponse: function (rsp, peerInfo, serviceTag, callback) {
Expand Down
139 changes: 82 additions & 57 deletions test/multicast-dns.spec.js
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Original file line number Diff line number Diff line change
Expand Up @@ -7,22 +7,29 @@ const expect = chai.expect
chai.use(dirtyChai)
const multiaddr = require('multiaddr')
const PeerInfo = require('peer-info')
const PeerId = require('peer-id')
const parallel = require('async/parallel')
const series = require('async/series')

const MulticastDNS = require('./../src')

function createPeer (callback) {
PeerId.create({ bits: 512 }, (err, id) => {
if (err) throw err
PeerInfo.create(id, callback)
})
}

describe('MulticastDNS', () => {
let pA
let pB
let pC
let pD

before(function (done) {
this.timeout(80 * 1000)
parallel([
(cb) => {
PeerInfo.create((err, peer) => {
createPeer((err, peer) => {
expect(err).to.not.exist()

pA = peer
Expand All @@ -31,7 +38,7 @@ describe('MulticastDNS', () => {
})
},
(cb) => {
PeerInfo.create((err, peer) => {
createPeer((err, peer) => {
expect(err).to.not.exist()

pB = peer
Expand All @@ -41,7 +48,7 @@ describe('MulticastDNS', () => {
})
},
(cb) => {
PeerInfo.create((err, peer) => {
createPeer((err, peer) => {
expect(err).to.not.exist()
pC = peer
pC.multiaddrs.add(multiaddr('/ip4/127.0.0.1/tcp/20003'))
Expand All @@ -50,7 +57,7 @@ describe('MulticastDNS', () => {
})
},
(cb) => {
PeerInfo.create((err, peer) => {
createPeer((err, peer) => {
if (err) { cb(err) }
pD = peer
pD.multiaddrs.add(multiaddr('/ip4/127.0.0.1/tcp/30003/ws'))
Expand All @@ -61,8 +68,6 @@ describe('MulticastDNS', () => {
})

it('find another peer', function (done) {
this.timeout(40 * 1000)

const options = {
port: 50001 // port must be the same
}
Expand All @@ -72,25 +77,22 @@ describe('MulticastDNS', () => {
})
const mdnsB = new MulticastDNS(pB, options)

mdnsA.once('peer', (peerInfo) => {
expect(pB.id.toB58String()).to.eql(peerInfo.id.toB58String())
parallel([
(cb) => mdnsA.stop(cb),
(cb) => mdnsB.stop(cb)
], done)
})

mdnsB.once('peer', (peerInfo) => {})
parallel([
(cb) => mdnsA.start(cb),
(cb) => mdnsB.start(cb)
], () => {
mdnsA.once('peer', (peerInfo) => {
expect(pB.id.toB58String()).to.eql(peerInfo.id.toB58String())
parallel([
(cb) => mdnsA.stop(cb),
(cb) => mdnsB.stop(cb)
], done)
})

mdnsB.once('peer', (peerInfo) => {})
})
], () => {})
})

it('only announce TCP multiaddrs', function (done) {
this.timeout(40 * 1000)

const options = {
port: 50003 // port must be the same
}
Expand All @@ -102,74 +104,97 @@ describe('MulticastDNS', () => {
const mdnsC = new MulticastDNS(pC, options)
const mdnsD = new MulticastDNS(pD, options)

mdnsA.once('peer', (peerInfo) => {
expect(pC.id.toB58String()).to.eql(peerInfo.id.toB58String())
expect(peerInfo.multiaddrs.size).to.equal(1)
parallel([
(cb) => mdnsA.stop(cb),
(cb) => mdnsC.stop(cb),
(cb) => mdnsD.stop(cb)
], done)
})
mdnsC.once('peer', (peerInfo) => {})
parallel([
(cb) => mdnsA.start(cb),
(cb) => mdnsC.start(cb),
(cb) => mdnsD.start(cb)

], () => {
mdnsA.once('peer', (peerInfo) => {
expect(pC.id.toB58String()).to.eql(peerInfo.id.toB58String())
expect(peerInfo.multiaddrs.size).to.equal(1)
parallel([
(cb) => mdnsA.stop(cb),
(cb) => mdnsC.stop(cb),
(cb) => mdnsD.stop(cb)
], done)
})

mdnsC.once('peer', (peerInfo) => {})
})
], () => {})
})

it('announces IP6 addresses', function (done) {
this.timeout(40 * 1000)

const options = {
port: 50001 // port must be the same
}
const mdnsA = new MulticastDNS(pA, {
broadcast: false, // do not talk to ourself
port: 50001
})
const mdnsA = new MulticastDNS(pA, options)
const mdnsB = new MulticastDNS(pB, options)

mdnsA.once('peer', (peerInfo) => {
expect(pB.id.toB58String()).to.eql(peerInfo.id.toB58String())
expect(peerInfo.multiaddrs.size).to.equal(2)
parallel([
(cb) => mdnsA.stop(cb),
(cb) => mdnsB.stop(cb)
], done)
})
mdnsB.once('peer', (peerInfo) => {})
series([
(cb) => mdnsB.start(cb),
(cb) => mdnsA.start(cb)
], () => {
mdnsA.once('peer', (peerInfo) => {
expect(pB.id.toB58String()).to.eql(peerInfo.id.toB58String())
expect(peerInfo.multiaddrs.size).to.equal(2)
parallel([
(cb) => mdnsA.stop(cb),
(cb) => mdnsB.stop(cb)
], done)
})

mdnsB.once('peer', (peerInfo) => {})
})
], () => {})
})

it('doesn\'t emit peers after stop', function (done) {
this.timeout(40 * 1000)

const options = {
port: 50004 // port must be the same
}
const mdnsA = new MulticastDNS(pA, options)
const mdnsC = new MulticastDNS(pC, options)
mdnsC.once('peer', (peerInfo) => {
done(new Error('Should not receive new peer.'))
})

series([
(cb) => mdnsA.start(cb),
(cb) => setTimeout(cb, 1000),
(cb) => mdnsA.stop(cb),
(cb) => mdnsC.start(cb)
], () => {
setTimeout(() => mdnsC.stop(done), 5000)
mdnsC.once('peer', (peerInfo) => {
done(new Error('Should not receive new peer.'))
})
setTimeout(() => mdnsC.stop(done), 1000)
})
})

it('find all peers', function (done) {
const options = {
port: 50001 // port must be the same
}
const mdnsA = new MulticastDNS(pA, options)
const mdnsB = new MulticastDNS(pB, options)
const mdnsC = new MulticastDNS(pC, options)
const peersA = {}
const peersB = {}
const peersC = {}

// After all the peers have started, each peer should see two other peers.
function check (receiver, peerInfo) {
receiver[peerInfo.id.toB58String()] = true
if (Object.keys(peersA).length === 2 && Object.keys(peersB).length === 2 && Object.keys(peersC).length === 2) {
parallel([
(cb) => mdnsA.stop(cb),
(cb) => mdnsB.stop(cb),
(cb) => mdnsC.stop(cb)
], done)
}
}
mdnsA.on('peer', (peerInfo) => check(peersA, peerInfo))
mdnsB.on('peer', (peerInfo) => check(peersB, peerInfo))
mdnsC.on('peer', (peerInfo) => check(peersC, peerInfo))
series([
(cb) => mdnsA.start(cb),
(cb) => setTimeout(cb, 500),
(cb) => mdnsB.start(cb),
(cb) => setTimeout(cb, 500),
(cb) => mdnsC.start(cb)
], () => {})
})
})