refactor: ping (#505)

* refactor: ping

* chore: ping is now a function

* chore: address review

Author: vasco-santos

doc/API.md

@@ -10,6 +10,7 @@
   * [`hangUp`](#hangUp)
   * [`handle`](#handle)
   * [`unhandle`](#unhandle)
+  * [`ping`](#ping)
   * [`peerRouting.findPeer`](#peerRouting.findPeer)
   * [`contentRouting.findProviders`](#contentRouting.findProviders)
   * [`contentRouting.provide`](#contentRouting.provide)
@@ -307,6 +308,31 @@ Unregisters all handlers with the given protocols
 libp2p.unhandle(['/echo/1.0.0'])
 ```
 
+### ping
+
+Pings a given peer and get the operation's latency.
+
+`libp2p.ping(peer)`
+
+#### Parameters
+
+| Name | Type | Description |
+|------|------|-------------|
+| peer | `PeerInfo|PeerId|Multiaddr|string` | peer to ping |
+
+#### Returns
+
+| Type | Description |
+|------|-------------|
+| `Promise<number>` | Latency of the operation in ms |
+
+#### Example
+
+```js
+// ...
+const latency = await libp2p.ping(otherPeerId)
+```
+
 ### peerRouting.findPeer
 
 Iterates over all peer routers in series to find the given peer. If the DHT is enabled, it will be tried first.

package.json

@@ -50,6 +50,7 @@
     "err-code": "^1.1.2",
     "hashlru": "^2.3.0",
     "it-all": "^1.0.1",
+    "it-buffer": "^0.1.1",
     "it-handshake": "^1.0.1",
     "it-length-prefixed": "^3.0.0",
     "it-pipe": "^1.1.0",

src/identify/index.js

@@ -9,7 +9,7 @@ const { collect, take } = require('streaming-iterables')
 const PeerInfo = require('peer-info')
 const PeerId = require('peer-id')
 const multiaddr = require('multiaddr')
-const { toBuffer } = require('../util')
+const { toBuffer } = require('it-buffer')
 
 const Message = require('./message')
 

src/index.js

@@ -21,6 +21,7 @@ const TransportManager = require('./transport-manager')
 const Upgrader = require('./upgrader')
 const PeerStore = require('./peer-store')
 const Registrar = require('./registrar')
+const ping = require('./ping')
 const {
   IdentifyService,
   multicodecs: IDENTIFY_PROTOCOLS
@@ -148,6 +149,9 @@ class Libp2p extends EventEmitter {
     this.peerRouting = peerRouting(this)
     this.contentRouting = contentRouting(this)
 
+    // Mount default protocols
+    ping.mount(this)
+
     this._onDiscoveryPeer = this._onDiscoveryPeer.bind(this)
   }
 
@@ -203,6 +207,8 @@ class Libp2p extends EventEmitter {
 
       await this.transportManager.close()
       await this.registrar.close()
+
+      ping.unmount(this)
     } catch (err) {
       if (err) {
         log.error(err)
@@ -280,17 +286,16 @@ class Libp2p extends EventEmitter {
     )
   }
 
-  // TODO: Update ping
-  // /**
-  //  * Pings the provided peer
-  //  *
-  //  * @param {PeerInfo|PeerId|Multiaddr|string} peer The peer to ping
-  //  * @returns {Promise<Ping>}
-  //  */
-  // ping (peer) {
-  //   const peerInfo = await getPeerInfoRemote(peer, this)
-  //   return new Ping(this._switch, peerInfo)
-  // }
+  /**
+   * Pings the given peer
+   * @param {PeerInfo|PeerId|Multiaddr|string} peer The peer to ping
+   * @returns {Promise<number>}
+   */
+  async ping (peer) {
+    const peerInfo = await getPeerInfo(peer, this.peerStore)
+
+    return ping(this, peerInfo)
+  }
 
   /**
    * Registers the `handler` for each protocol

src/ping/README.md

@@ -8,16 +8,11 @@ libp2p-ping JavaScript Implementation
 ## Usage
 
 ```javascript
-var Ping = require('libp2p-ping')
+var Ping = require('libp2p/src/ping')
 
-Ping.mount(swarm) // Enable this peer to echo Ping requests
+Ping.mount(libp2p) // Enable this peer to echo Ping requests
 
-var p = new Ping(swarm, peerDst) // Ping peerDst, peerDst must be a peer-info object
+const latency = await Ping(libp2p, peerDst)
 
-p.on('ping', function (time) {
-  console.log(time + 'ms')
-  p.stop() // stop sending pings
-})
-
-p.start()
+Ping.unmount(libp2p)
 ```

src/ping/handler.js

@@ -1,7 +1,62 @@
 'use strict'
 
-const handler = require('./handler')
+const debug = require('debug')
+const log = debug('libp2p-ping')
+log.error = debug('libp2p-ping:error')
+const errCode = require('err-code')
 
-exports = module.exports = require('./ping')
-exports.mount = handler.mount
-exports.unmount = handler.unmount
+const crypto = require('libp2p-crypto')
+const pipe = require('it-pipe')
+const { toBuffer } = require('it-buffer')
+const { collect } = require('streaming-iterables')
+
+const { PROTOCOL, PING_LENGTH } = require('./constants')
+
+/**
+ * Ping a given peer and wait for its response, getting the operation latency.
+ * @param {Libp2p} node
+ * @param {PeerInfo} peer
+ * @returns {Promise<Number>}
+ */
+async function ping (node, peer) {
+  log('dialing %s to %s', PROTOCOL, peer.id.toB58String())
+
+  const { stream } = await node.dialProtocol(peer, PROTOCOL)
+
+  const start = new Date()
+  const data = crypto.randomBytes(PING_LENGTH)
+
+  const [result] = await pipe(
+    [data],
+    stream,
+    toBuffer,
+    collect
+  )
+  const end = Date.now()
+
+  if (!data.equals(result)) {
+    throw errCode(new Error('Received wrong ping ack'), 'ERR_WRONG_PING_ACK')
+  }
+
+  return end - start
+}
+
+/**
+ * Subscribe ping protocol handler.
+ * @param {Libp2p} node
+ */
+function mount (node) {
+  node.handle(PROTOCOL, ({ stream }) => pipe(stream, stream))
+}
+
+/**
+ * Unsubscribe ping protocol handler.
+ * @param {Libp2p} node
+ */
+function unmount (node) {
+  node.unhandle(PROTOCOL)
+}
+
+exports = module.exports = ping
+exports.mount = mount
+exports.unmount = unmount

src/ping/index.js

@@ -0,0 +1,35 @@
+'use strict'
+/* eslint-env mocha */
+
+const chai = require('chai')
+chai.use(require('dirty-chai'))
+const { expect } = chai
+
+const pTimes = require('p-times')
+
+const peerUtils = require('../utils/creators/peer')
+const baseOptions = require('../utils/base-options')
+
+describe('ping', () => {
+  let nodes
+
+  beforeEach(async () => {
+    nodes = await peerUtils.createPeer({
+      number: 2,
+      config: baseOptions
+    })
+  })
+
+  it('ping once from peer0 to peer1', async () => {
+    const latency = await nodes[0].ping(nodes[1].peerInfo)
+
+    expect(latency).to.be.a('Number')
+  })
+
+  it('ping several times for getting an average', async () => {
+    const latencies = await pTimes(5, () => nodes[1].ping(nodes[0].peerInfo))
+
+    const averageLatency = latencies.reduce((p, c) => p + c, 0) / latencies.length
+    expect(averageLatency).to.be.a('Number')
+  })
+})