feat: allow passing ProvidersInit in KadDHT constructor (libp2p#404)

The `Providers` component takes a `ProvidersInit` object, but there's not actually a way to provide it with one from the `KadDHT` constructor. This means users aren't able to override the defaults for how long provider records are valid for and how frequently to clean up expired provider records.

Co-authored-by: Alex Potsides <alex@achingbrain.net>

src/index.ts

@@ -1,5 +1,6 @@
 import { KadDHT as SingleKadDHT } from './kad-dht.js'
 import { DualKadDHT } from './dual-kad-dht.js'
+import type { ProvidersInit } from './providers.js'
 import type { Selectors, Validators } from '@libp2p/interface-dht'
 import type { Registrar } from '@libp2p/interface-registrar'
 import type { AddressManager } from '@libp2p/interface-address-manager'
@@ -62,6 +63,11 @@ export interface KadDHTInit {
    * How many parallel outgoing streams to allow on the DHT protocol per-connection
    */
   maxOutboundStreams?: number
+
+  /**
+   * Initialization options for the Providers component
+   */
+  providers?: ProvidersInit
 }
 
 export interface KadDHTComponents {

src/kad-dht.ts

@@ -82,7 +82,8 @@ export class KadDHT extends EventEmitter<PeerDiscoveryEvents> implements DHT {
       pingTimeout,
       pingConcurrency,
       maxInboundStreams,
-      maxOutboundStreams
+      maxOutboundStreams,
+      providers: providersInit
     } = init
 
     this.running = false
@@ -102,7 +103,7 @@ export class KadDHT extends EventEmitter<PeerDiscoveryEvents> implements DHT {
       protocol: this.protocol
     })
 
-    this.providers = new Providers(components)
+    this.providers = new Providers(components, providersInit ?? {})
 
     this.validators = {
       ...recordValidators,

test/kad-dht.spec.ts

@@ -91,6 +91,20 @@ describe('KadDHT', () => {
       expect(dht).to.have.property('getMode')
       expect(dht).to.have.property('setMode')
     })
+
+    it('forward providers init options to providers component', async () => {
+      const dht = await tdht.spawn({
+        kBucketSize: 5,
+        providers: {
+          cleanupInterval: 60,
+          provideValidity: 60 * 10
+        }
+      })
+      expect(dht.lan.providers).to.have.property('cleanupInterval', 60)
+      expect(dht.lan.providers).to.have.property('provideValidity', 60 * 10)
+      expect(dht.wan.providers).to.have.property('cleanupInterval', 60)
+      expect(dht.wan.providers).to.have.property('provideValidity', 60 * 10)
+    })
   })
 
   describe('start and stop', () => {