feat: async peerstore backed by datastores (#1058)

We have a peerstore that keeps all data for all observed peers in memory with no eviction.

This is fine when you don't discover many peers but when using the DHT you encounter a significant number of peers so our peer storage grows and grows over time.

We have a persistent peer store, but it just periodically writes peers into the datastore to be read at startup, still keeping them in memory.

It also means a restart doesn't give you any temporary reprieve from the memory leak as the previously observed peer data is read into memory at startup.

This change refactors the peerstore to use a datastore by default, reading and writing peer info as it arrives.  It can be configured with a MemoryDatastore if desired.

It was necessary to change the peerstore and *book interfaces to be asynchronous since the datastore api is asynchronous.

BREAKING CHANGE: `libp2p.handle`, `libp2p.registrar.register` and the peerstore methods have become async

examples/discovery-mechanisms/3.js

@@ -5,7 +5,7 @@ const Libp2p = require('../../')
 const TCP = require('libp2p-tcp')
 const Mplex = require('libp2p-mplex')
 const { NOISE } = require('@chainsafe/libp2p-noise')
-const Gossipsub = require('libp2p-gossipsub')
+const Gossipsub = require('@achingbrain/libp2p-gossipsub')
 const Bootstrap = require('libp2p-bootstrap')
 const PubsubPeerDiscovery = require('libp2p-pubsub-peer-discovery')
 

examples/discovery-mechanisms/bootstrapers.js

@@ -1,13 +1,13 @@
 'use strict'
 
-// Find this list at: https://github.com/ipfs/js-ipfs/blob/master/packages/ipfs-core/src/runtime/config-nodejs.js
+// Find this list at: https://github.com/ipfs/js-ipfs/blob/master/packages/ipfs-core-config/src/config.js
 const bootstrapers = [
   '/ip4/104.131.131.82/tcp/4001/p2p/QmaCpDMGvV2BGHeYERUEnRQAwe3N8SzbUtfsmvsqQLuvuJ',
   '/dnsaddr/bootstrap.libp2p.io/p2p/QmNnooDu7bfjPFoTZYxMNLWUQJyrVwtbZg5gBMjTezGAJN',
   '/dnsaddr/bootstrap.libp2p.io/p2p/QmbLHAnMoJPWSCR5Zhtx6BHJX9KiKNN6tpvbUcqanj75Nb',
   '/dnsaddr/bootstrap.libp2p.io/p2p/QmZa1sAxajnQjVM8WjWXoMbmPd7NsWhfKsPkErzpm9wGkp',
   '/dnsaddr/bootstrap.libp2p.io/p2p/QmQCU2EcMqAqQPR2i9bChDtGNJchTbq5TbXJJ16u19uLTa',
-  '/dnsaddr/bootstrap.libp2p.io/p2p/QmcZf59bWwK5XFi76CZX8cbJ4BhTzzA3gU1ZjYZcYW3dwt'
+  '/dnsaddr/bootstrap.libp2p.io/p2p/QmcZf59bWwK5XFi76CZX8cbJ4BhTzzA3gU1ZjYZcYW3dwt',
 ]
 
 module.exports = bootstrapers

examples/discovery-mechanisms/test-1.js

@@ -2,17 +2,9 @@
 
 const path = require('path')
 const execa = require('execa')
-const pWaitFor = require('p-wait-for')
 const { toString: uint8ArrayToString } = require('uint8arrays/to-string')
-const bootstrapers = require('./bootstrapers')
-
-const discoveredCopy = 'Discovered:'
-const connectedCopy = 'Connection established to:'
 
 async function test () {
-  const discoveredNodes = []
-  const connectedNodes = []
-
   process.stdout.write('1.js\n')
 
   const proc = execa('node', [path.join(__dirname, '1.js')], {
@@ -20,23 +12,17 @@ async function test () {
     all: true
   })
 
+  let output = ''
+
   proc.all.on('data', async (data) => {
     process.stdout.write(data)
-    const line = uint8ArrayToString(data)
+    output += uint8ArrayToString(data)
 
-    // Discovered or Connected
-    if (line.includes(discoveredCopy)) {
-      const id = line.trim().split(discoveredCopy)[1]
-      discoveredNodes.push(id)
-    } else if (line.includes(connectedCopy)) {
-      const id = line.trim().split(connectedCopy)[1]
-      connectedNodes.push(id)
+    // Discovered and connected
+    if (output.includes('Connection established to:')) {
+      proc.kill()
     }
   })
-
-  await pWaitFor(() => discoveredNodes.length === bootstrapers.length && connectedNodes.length === bootstrapers.length)
-
-  proc.kill()
 }
 
 module.exports = test