refactor: stats (#501)

* docs: add initial notes on stats

* feat: initial refactor of stats to metrics

* feat: add support for placeholder metrics

This is helpful for tracking metrics prior to knowing the remote peers id

* fix: add metrics tests and fix issues

* fix: always clear the dial timeout timer

* docs: add metrics to api doc

* chore: apply suggestions from code review

Co-Authored-By: Vasco Santos <vasco.santos@moxy.studio>

* docs: update metrics docs

* fix: call metrics.onDisconnect

* docs(config): add example headers so they appear in the TOC

* docs(config): add metrics configuration

* docs(relay): fix relay configuration docs

src/upgrader.js

@@ -8,6 +8,7 @@ const { Connection } = require('libp2p-interfaces/src/connection')
 const PeerId = require('peer-id')
 const pipe = require('it-pipe')
 const errCode = require('err-code')
+const mutableProxy = require('mutable-proxy')
 
 const { codes } = require('./errors')
 
@@ -30,6 +31,7 @@ class Upgrader {
   /**
    * @param {object} options
    * @param {PeerId} options.localPeer
+   * @param {Metrics} options.metrics
    * @param {Map<string, Crypto>} options.cryptos
    * @param {Map<string, Muxer>} options.muxers
    * @param {function(Connection)} options.onConnection Called when a connection is upgraded
@@ -37,12 +39,14 @@ class Upgrader {
    */
   constructor ({
     localPeer,
+    metrics,
     cryptos,
     muxers,
     onConnectionEnd = () => {},
     onConnection = () => {}
   }) {
     this.localPeer = localPeer
+    this.metrics = metrics
     this.cryptos = cryptos || new Map()
     this.muxers = muxers || new Map()
     this.protector = null
@@ -63,6 +67,15 @@ class Upgrader {
     let muxedConnection
     let Muxer
     let cryptoProtocol
+    let setPeer
+    let proxyPeer
+
+    if (this.metrics) {
+      ({ setTarget: setPeer, proxy: proxyPeer } = mutableProxy())
+      const idString = (parseInt(Math.random() * 1e9)).toString(36) + Date.now()
+      setPeer({ toString: () => idString })
+      maConn = this.metrics.trackStream({ stream: maConn, remotePeer: proxyPeer })
+    }
 
     log('Starting the inbound connection upgrade')
 
@@ -89,6 +102,11 @@ class Upgrader {
       throw err
     }
 
+    if (this.metrics) {
+      this.metrics.updatePlaceholder(proxyPeer, remotePeer)
+      setPeer(remotePeer)
+    }
+
     log('Successfully upgraded inbound connection')
 
     return this._createConnection({
@@ -120,6 +138,15 @@ class Upgrader {
     let muxedConnection
     let cryptoProtocol
     let Muxer
+    let setPeer
+    let proxyPeer
+
+    if (this.metrics) {
+      ({ setTarget: setPeer, proxy: proxyPeer } = mutableProxy())
+      const idString = (parseInt(Math.random() * 1e9)).toString(36) + Date.now()
+      setPeer({ toString: () => idString })
+      maConn = this.metrics.trackStream({ stream: maConn, remotePeer: proxyPeer })
+    }
 
     log('Starting the outbound connection upgrade')
 
@@ -145,6 +172,11 @@ class Upgrader {
       throw err
     }
 
+    if (this.metrics) {
+      this.metrics.updatePlaceholder(proxyPeer, remotePeer)
+      setPeer(remotePeer)
+    }
+
     log('Successfully upgraded outbound connection')
 
     return this._createConnection({
@@ -185,6 +217,7 @@ class Upgrader {
         try {
           const { stream, protocol } = await mss.handle(Array.from(this.protocols.keys()))
           log('%s: incoming stream opened on %s', direction, protocol)
+          if (this.metrics) this.metrics.trackStream({ stream, remotePeer, protocol })
           connection.addStream(stream, protocol)
           this._onStream({ connection, stream, protocol })
         } catch (err) {
@@ -203,6 +236,7 @@ class Upgrader {
       const mss = new Multistream.Dialer(muxedStream)
       try {
         const { stream, protocol } = await mss.select(protocols)
+        if (this.metrics) this.metrics.trackStream({ stream, remotePeer, protocol })
         return { stream: { ...muxedStream, ...stream }, protocol }
       } catch (err) {
         log.error('could not create new stream', err)