fix: add tracked map (#1069)

Small refactor of the component stats - adds a `TrackedMap` which encapsulates updating the metrics and means we don't need to null guard on `this._metrics` everywhere.

If metrics are not enabled a regular `Map` is used.

src/connection-manager/index.js

@@ -12,7 +12,7 @@ const LatencyMonitor = require('./latency-monitor')
 const retimer = require('retimer')
 
 const { EventEmitter } = require('events')
-
+const trackedMap = require('../metrics/tracked-map')
 const PeerId = require('peer-id')
 
 const {
@@ -34,7 +34,7 @@ const defaultOptions = {
 
 const METRICS_COMPONENT = 'connection-manager'
 const METRICS_PEER_CONNECTIONS = 'peer-connections'
-const METRICS_ALL_CONNECTIONS = 'all-connections'
+const METRICS_PEER_VALUES = 'peer-values'
 
 /**
  * @typedef {import('../')} Libp2p
@@ -87,14 +87,14 @@ class ConnectionManager extends EventEmitter {
      *
      * @type {Map<string, number>}
      */
-    this._peerValues = new Map()
+    this._peerValues = trackedMap(METRICS_COMPONENT, METRICS_PEER_VALUES, this._libp2p.metrics)
 
     /**
      * Map of connections per peer
      *
      * @type {Map<string, Connection[]>}
      */
-    this.connections = new Map()
+    this.connections = trackedMap(METRICS_COMPONENT, METRICS_PEER_CONNECTIONS, this._libp2p.metrics)
 
     this._started = false
     this._timer = null
@@ -164,8 +164,6 @@ class ConnectionManager extends EventEmitter {
 
     await Promise.all(tasks)
     this.connections.clear()
-    this._libp2p.metrics && this._libp2p.metrics.updateComponentMetric(METRICS_COMPONENT, METRICS_PEER_CONNECTIONS, 0)
-    this._libp2p.metrics && this._libp2p.metrics.updateComponentMetric(METRICS_COMPONENT, METRICS_ALL_CONNECTIONS, 0)
   }
 
   /**
@@ -222,8 +220,6 @@ class ConnectionManager extends EventEmitter {
       storedConn.push(connection)
     } else {
       this.connections.set(peerIdStr, [connection])
-      this._libp2p.metrics && this._libp2p.metrics.updateComponentMetric(METRICS_COMPONENT, METRICS_PEER_CONNECTIONS, this.connections.size)
-      this._libp2p.metrics && this._libp2p.metrics.updateComponentMetric(METRICS_COMPONENT, METRICS_ALL_CONNECTIONS, this.size)
     }
 
     this._libp2p.peerStore.keyBook.set(peerId, peerId.pubKey)
@@ -255,9 +251,6 @@ class ConnectionManager extends EventEmitter {
 
       this._libp2p.metrics && this._libp2p.metrics.onPeerDisconnected(connection.remotePeer)
     }
-
-    this._libp2p.metrics && this._libp2p.metrics.updateComponentMetric(METRICS_COMPONENT, METRICS_PEER_CONNECTIONS, this.connections.size)
-    this._libp2p.metrics && this._libp2p.metrics.updateComponentMetric(METRICS_COMPONENT, METRICS_ALL_CONNECTIONS, this.size)
   }
 
   /**

src/dialer/index.js

@@ -14,7 +14,7 @@ const { setMaxListeners } = require('events')
 const DialRequest = require('./dial-request')
 const { publicAddressesFirst } = require('libp2p-utils/src/address-sort')
 const getPeer = require('../get-peer')
-
+const trackedMap = require('../metrics/tracked-map')
 const { codes } = require('../errors')
 const {
   DIAL_TIMEOUT,
@@ -86,9 +86,12 @@ class Dialer {
     this.timeout = dialTimeout
     this.maxDialsPerPeer = maxDialsPerPeer
     this.tokens = [...new Array(maxParallelDials)].map((_, index) => index)
-    this._pendingDials = new Map()
+
-    this._pendingDialTargets = new Map()
+    /** @type {Map<string, PendingDial>} */
-    this._metrics = metrics
+    this._pendingDials = trackedMap(METRICS_COMPONENT, METRICS_PENDING_DIALS, metrics)
+
+    /** @type {Map<string, { resolve: (value: any) => void, reject: (err: Error) => void}>} */
+    this._pendingDialTargets = trackedMap(METRICS_COMPONENT, METRICS_PENDING_DIAL_TARGETS, metrics)
 
     for (const [key, value] of Object.entries(resolvers)) {
       Multiaddr.resolvers.set(key, value)
@@ -112,9 +115,6 @@ class Dialer {
       pendingTarget.reject(new AbortError('Dialer was destroyed'))
     }
     this._pendingDialTargets.clear()
-
-    this._metrics && this._metrics.updateComponentMetric(METRICS_COMPONENT, METRICS_PENDING_DIALS, 0)
-    this._metrics && this._metrics.updateComponentMetric(METRICS_COMPONENT, METRICS_PENDING_DIAL_TARGETS, 0)
   }
 
   /**
@@ -164,7 +164,6 @@ class Dialer {
     const id = `${(parseInt(String(Math.random() * 1e9), 10)).toString() + Date.now()}`
     const cancellablePromise = new Promise((resolve, reject) => {
       this._pendingDialTargets.set(id, { resolve, reject })
-      this._metrics && this._metrics.updateComponentMetric(METRICS_COMPONENT, METRICS_PENDING_DIAL_TARGETS, this._pendingDialTargets.size)
     })
 
     try {
@@ -176,7 +175,6 @@ class Dialer {
       return dialTarget
     } finally {
       this._pendingDialTargets.delete(id)
-      this._metrics && this._metrics.updateComponentMetric(METRICS_COMPONENT, METRICS_PENDING_DIAL_TARGETS, this._pendingDialTargets.size)
     }
   }
 
@@ -269,13 +267,10 @@ class Dialer {
       destroy: () => {
         timeoutController.clear()
         this._pendingDials.delete(dialTarget.id)
-        this._metrics && this._metrics.updateComponentMetric(METRICS_COMPONENT, METRICS_PENDING_DIALS, this._pendingDials.size)
       }
     }
     this._pendingDials.set(dialTarget.id, pendingDial)
 
-    this._metrics && this._metrics.updateComponentMetric(METRICS_COMPONENT, METRICS_PENDING_DIALS, this._pendingDials.size)
-
     return pendingDial
   }
 

src/index.js

@@ -161,6 +161,15 @@ class Libp2p extends EventEmitter {
     this.peerId = this._options.peerId
     this.datastore = this._options.datastore
 
+    // Create Metrics
+    if (this._options.metrics.enabled) {
+      const metrics = new Metrics({
+        ...this._options.metrics
+      })
+
+      this.metrics = metrics
+    }
+
     this.peerStore = (this.datastore && this._options.peerStore.persistence)
       ? new PersistentPeerStore({
         peerId: this.peerId,
@@ -195,15 +204,6 @@ class Libp2p extends EventEmitter {
       autoDialInterval: this._options.connectionManager.autoDialInterval
     })
 
-    // Create Metrics
-    if (this._options.metrics.enabled) {
-      const metrics = new Metrics({
-        ...this._options.metrics
-      })
-
-      this.metrics = metrics
-    }
-
     // Create keychain
     if (this._options.keychain && this._options.keychain.datastore) {
       log('creating keychain')

src/metrics/tracked-map.js

@@ -0,0 +1,62 @@
+'use strict'
+
+/**
+ * @template K
+ * @template V
+ */
+class TrackedMap extends Map {
+  /**
+   * @param {string} component
+   * @param {string} name
+   * @param {import('.')} metrics
+   */
+  constructor (component, name, metrics) {
+    super()
+
+    this._component = component
+    this._name = name
+    this._metrics = metrics
+
+    this._metrics.updateComponentMetric(this._component, this._name, this.size)
+  }
+
+  /**
+   * @param {K} key
+   * @param {V} value
+   */
+  set (key, value) {
+    super.set(key, value)
+    this._metrics.updateComponentMetric(this._component, this._name, this.size)
+    return this
+  }
+
+  /**
+   * @param {K} key
+   */
+  delete (key) {
+    const deleted = super.delete(key)
+    this._metrics.updateComponentMetric(this._component, this._name, this.size)
+    return deleted
+  }
+}
+
+/**
+ * @template K
+ * @template V
+ * @param {string} component
+ * @param {string} name
+ * @param {import('.')} [metrics]
+ * @returns {Map<K, V>}
+ */
+module.exports = (component, name, metrics) => {
+  /** @type {Map<K, V>} */
+  let map
+
+  if (metrics) {
+    map = new TrackedMap(component, name, metrics)
+  } else {
+    map = new Map()
+  }
+
+  return map
+}