refactor: callbacks -> async / await (#78)

BREAKING CHANGE: All places in the API that used callbacks are now replaced with async/await

* chore: update CI file
* test: add compliance tests

.travis.yml

@@ -7,22 +7,20 @@ stages:
 
 node_js:
   - '10'
+  - '12'
 
 os:
   - linux
   - osx
+  - windows
 
 script: npx nyc -s npm run test:node -- --bail
 after_success: npx nyc report --reporter=text-lcov > coverage.lcov && npx codecov
 
 jobs:
   include:
-    - os: windows
-      cache: false
-
     - stage: check
       script:
-        - npx aegir commitlint --travis
         - npx aegir dep-check
         - npm run lint
 

README.md

@@ -28,7 +28,8 @@ mdns.on('peer', (peerInfo) => {
 })
 
 // Broadcast for 20 seconds
-mdns.start(() => setTimeout(() => mdns.stop(() => {}), 20 * 1000))
+mdns.start()
+setTimeout(() => mdns.stop(), 20 * 1000)
 ```
 
 - options

package.json

@@ -34,18 +34,20 @@
   },
   "homepage": "https://github.com/libp2p/js-libp2p-mdns",
   "devDependencies": {
-    "aegir": "^18.2.2",
+    "aegir": "^20.3.1",
     "chai": "^4.2.0",
-    "dirty-chai": "^2.0.1"
+    "delay": "^4.3.0",
+    "dirty-chai": "^2.0.1",
+    "interface-discovery": "^0.1.1",
+    "p-defer": "^3.0.0"
   },
   "dependencies": {
     "async": "^2.6.2",
     "debug": "^4.1.1",
-    "libp2p-tcp": "~0.13.0",
-    "multiaddr": "^6.0.6",
+    "multiaddr": "^7.1.0",
     "multicast-dns": "^7.2.0",
-    "peer-id": "~0.12.2",
-    "peer-info": "~0.15.1"
+    "peer-id": "~0.13.3",
+    "peer-info": "~0.17.0"
   },
   "contributors": [
     "Alan Shaw <alan.shaw@protocol.ai>",

src/compat/index.js

@@ -3,7 +3,6 @@
 // Compatibility with Go libp2p MDNS
 
 const EE = require('events')
-const parallel = require('async/parallel')
 const Responder = require('./responder')
 const Querier = require('./querier')
 
@@ -15,9 +14,9 @@ class GoMulticastDNS extends EE {
     this._onPeer = this._onPeer.bind(this)
   }
 
-  start (callback) {
+  async start () {
     if (this._started) {
-      return callback(new Error('MulticastDNS service is already started'))
+      return
     }
 
     this._started = true
@@ -26,20 +25,18 @@ class GoMulticastDNS extends EE {
 
     this._querier.on('peer', this._onPeer)
 
-    parallel([
-      cb => this._responder.start(cb),
-      cb => this._querier.start(cb)
-    ], callback)
+    await Promise.all([
+      this._responder.start(),
+      this._querier.start()
+    ])
   }
 
   _onPeer (peerInfo) {
     this.emit('peer', peerInfo)
   }
 
-  stop (callback) {
-    if (!this._started) {
-      return callback(new Error('MulticastDNS service is not started'))
-    }
+  stop () {
+    if (!this._started) return
 
     const responder = this._responder
     const querier = this._querier
@@ -50,10 +47,10 @@ class GoMulticastDNS extends EE {
 
     querier.removeListener('peer', this._onPeer)
 
-    parallel([
-      cb => responder.stop(cb),
-      cb => querier.stop(cb)
-    ], callback)
+    return Promise.all([
+      responder.stop(),
+      querier.stop()
+    ])
   }
 }
 

src/compat/querier.js

@@ -6,8 +6,9 @@ const MDNS = require('multicast-dns')
 const Multiaddr = require('multiaddr')
 const PeerInfo = require('peer-info')
 const PeerId = require('peer-id')
-const nextTick = require('async/nextTick')
-const log = require('debug')('libp2p:mdns:compat:querier')
+const debug = require('debug')
+const log = debug('libp2p:mdns:compat:querier')
+log.error = debug('libp2p:mdns:compat:querier:error')
 const { SERVICE_TAG_LOCAL, MULTICAST_IP, MULTICAST_PORT } = require('./constants')
 
 class Querier extends EE {
@@ -28,7 +29,7 @@ class Querier extends EE {
     this._onResponse = this._onResponse.bind(this)
   }
 
-  start (callback) {
+  start () {
     this._handle = periodically(() => {
       // Create a querier that queries multicast but gets responses unicast
       const mdns = MDNS({ multicast: false, interface: '0.0.0.0', port: 0 })
@@ -44,20 +45,18 @@ class Querier extends EE {
       })
 
       return {
-        stop: callback => {
+        stop: () => {
           mdns.removeListener('response', this._onResponse)
-          mdns.destroy(callback)
+          return new Promise(resolve => mdns.destroy(resolve))
         }
       }
     }, {
       period: this._options.queryPeriod,
       interval: this._options.queryInterval
     })
-
-    nextTick(() => callback())
   }
 
-  _onResponse (event, info) {
+  async _onResponse (event, info) {
     const answers = event.answers || []
     const ptrRecord = answers.find(a => a.type === 'PTR' && a.name === SERVICE_TAG_LOCAL)
 
@@ -87,37 +86,40 @@ class Querier extends EE {
       return log('failed to create peer ID from TXT record data', peerIdStr, err)
     }
 
-    PeerInfo.create(peerId, (err, info) => {
-      if (err) return log('failed to create peer info from peer ID', peerId, err)
+    let peerInfo
+    try {
+      peerInfo = await PeerInfo.create(peerId)
+    } catch (err) {
+      return log.error('failed to create peer info from peer ID', peerId, err)
+    }
 
-      const srvRecord = answers.find(a => a.type === 'SRV')
-      if (!srvRecord) return log('missing SRV record in response')
+    const srvRecord = answers.find(a => a.type === 'SRV')
+    if (!srvRecord) return log('missing SRV record in response')
 
-      log('peer found', peerIdStr)
+    log('peer found', peerIdStr)
 
-      const { port } = srvRecord.data || {}
-      const protos = { A: 'ip4', AAAA: 'ip6' }
+    const { port } = srvRecord.data || {}
+    const protos = { A: 'ip4', AAAA: 'ip6' }
 
-      const multiaddrs = answers
-        .filter(a => ['A', 'AAAA'].includes(a.type))
-        .reduce((addrs, a) => {
-          const maStr = `/${protos[a.type]}/${a.data}/tcp/${port}`
-          try {
-            addrs.push(new Multiaddr(maStr))
-            log(maStr)
-          } catch (err) {
-            log(`failed to create multiaddr from ${a.type} record data`, maStr, port, err)
-          }
-          return addrs
-        }, [])
+    const multiaddrs = answers
+      .filter(a => ['A', 'AAAA'].includes(a.type))
+      .reduce((addrs, a) => {
+        const maStr = `/${protos[a.type]}/${a.data}/tcp/${port}`
+        try {
+          addrs.push(new Multiaddr(maStr))
+          log(maStr)
+        } catch (err) {
+          log(`failed to create multiaddr from ${a.type} record data`, maStr, port, err)
+        }
+        return addrs
+      }, [])
 
-      multiaddrs.forEach(addr => info.multiaddrs.add(addr))
-      this.emit('peer', info)
-    })
+    multiaddrs.forEach(addr => peerInfo.multiaddrs.add(addr))
+    this.emit('peer', peerInfo)
   }
 
-  stop (callback) {
-    this._handle.stop(callback)
+  stop () {
+    return this._handle.stop()
   }
 }
 
@@ -140,27 +142,23 @@ function periodically (fn, options) {
 
   const reRun = () => {
     handle = fn()
-    timeoutId = setTimeout(() => {
-      handle.stop(err => {
-        if (err) log(err)
-        if (!stopped) {
-          timeoutId = setTimeout(reRun, options.interval)
-        }
-      })
+    timeoutId = setTimeout(async () => {
+      await handle.stop().catch(log)
+      if (!stopped) {
+        timeoutId = setTimeout(reRun, options.interval)
+      }
       handle = null
     }, options.period)
   }
 
   reRun()
 
   return {
-    stop (callback) {
+    stop () {
       stopped = true
       clearTimeout(timeoutId)
       if (handle) {
-        handle.stop(callback)
-      } else {
-        callback()
+        return handle.stop()
       }
     }
   }

src/compat/responder.js

@@ -4,12 +4,8 @@ const OS = require('os')
 const assert = require('assert')
 const MDNS = require('multicast-dns')
 const log = require('debug')('libp2p:mdns:compat:responder')
-const TCP = require('libp2p-tcp')
-const nextTick = require('async/nextTick')
 const { SERVICE_TAG_LOCAL } = require('./constants')
 
-const tcp = new TCP()
-
 class Responder {
   constructor (peerInfo) {
     assert(peerInfo, 'missing peerInfo parameter')
@@ -18,16 +14,15 @@ class Responder {
     this._onQuery = this._onQuery.bind(this)
   }
 
-  start (callback) {
+  start () {
     this._mdns = MDNS()
     this._mdns.on('query', this._onQuery)
-    nextTick(() => callback())
   }
 
   _onQuery (event, info) {
-    const multiaddrs = tcp.filter(this._peerInfo.multiaddrs.toArray())
+    const addresses = this._peerInfo.multiaddrs.toArray().map(ma => ma.toOptions())
     // Only announce TCP for now
-    if (!multiaddrs.length) return
+    if (!addresses.length) return
 
     const questions = event.questions || []
 
@@ -48,7 +43,7 @@ class Responder {
     })
 
     // Only announce TCP multiaddrs for now
-    const port = multiaddrs[0].toString().split('/')[4]
+    const port = addresses[0].port
 
     answers.push({
       name: peerServiceTagLocal,
@@ -71,15 +66,14 @@ class Responder {
       data: [Buffer.from(this._peerIdStr)]
     })
 
-    multiaddrs.forEach((ma) => {
-      const proto = ma.protoNames()[0]
-      if (proto === 'ip4' || proto === 'ip6') {
+    addresses.forEach((ma) => {
+      if (['ipv4', 'ipv6'].includes(ma.family)) {
         answers.push({
           name: OS.hostname(),
-          type: proto === 'ip4' ? 'A' : 'AAAA',
+          type: ma.family === 'ipv4' ? 'A' : 'AAAA',
           class: 'IN',
           ttl: 120,
-          data: ma.toString().split('/')[2]
+          data: ma.host
         })
       }
     })
@@ -88,9 +82,9 @@ class Responder {
     this._mdns.respond(answers, info)
   }
 
-  stop (callback) {
+  stop () {
     this._mdns.removeListener('query', this._onQuery)
-    this._mdns.destroy(callback)
+    return new Promise(resolve => this._mdns.destroy(resolve))
   }
 }