[PAY-1463] Fix d to set discovery node (#3690)

Co-authored-by: Michael Piazza <michael.piazza.mp@gmail.com>

packages/common/src/services/local-storage/LocalStorage.ts

@@ -7,8 +7,6 @@ import { Nullable } from '../../utils'
 
 // TODO: the following should come from @audius/libs/dist/core when
 // discoveryProvider/constants is migrated to typescript.
-const DISCOVERY_PROVIDER_TIMESTAMP = '@audius/libs:discovery-node-timestamp'
-
 const AUDIUS_ACCOUNT_KEY = '@audius/account'
 const AUDIUS_ACCOUNT_USER_KEY = '@audius/audius-user'
 
@@ -116,10 +114,4 @@ export class LocalStorage {
 
   getCurrentUserExists = async () =>
     this.getValue(CURRENT_USER_EXISTS_LOCAL_STORAGE_KEY)
-
-  async getCachedDiscoveryProvider() {
-    return await this.getJSONValue<CachedDiscoveryProviderType>(
-      DISCOVERY_PROVIDER_TIMESTAMP
-    )
-  }
 }

packages/common/src/services/sdk/discovery-node-selector/DiscoveryNodeSelectorService.ts

@@ -16,18 +16,24 @@ import {
 type DiscoveryNodeSelectorConfig = {
   env: Env
   remoteConfigInstance: RemoteConfigInstance
+  initialSelectedNode?: string
+  onChange?: (endpoint: string) => void
 }
 
 export class DiscoveryNodeSelectorService {
   private env: Env
   private remoteConfigInstance: RemoteConfigInstance
   private discoveryNodeSelectorPromise: Promise<DiscoveryNodeSelector> | null
+  private initialSelectedNode: string | undefined
+  private onChange: ((endpoint: string) => void) | undefined
 
   constructor(config: DiscoveryNodeSelectorConfig) {
-    const { env, remoteConfigInstance } = config
+    const { env, remoteConfigInstance, initialSelectedNode, onChange } = config
     this.env = env
     this.remoteConfigInstance = remoteConfigInstance
     this.discoveryNodeSelectorPromise = null
+    this.initialSelectedNode = initialSelectedNode
+    this.onChange = onChange
   }
 
   private async makeDiscoveryNodeSelector() {
@@ -59,12 +65,17 @@ export class DiscoveryNodeSelectorService {
     const requestTimeout =
       getRemoteVar(IntKeys.DISCOVERY_PROVIDER_SELECTION_TIMEOUT_MS) ?? undefined
 
-    return new DiscoveryNodeSelector({
+    const dnSelector = new DiscoveryNodeSelector({
       healthCheckThresholds,
       blocklist,
       requestTimeout,
-      bootstrapServices: discoveryNodes
+      bootstrapServices: discoveryNodes,
+      initialSelectedNode: this.initialSelectedNode
     })
+    if (this.onChange) {
+      dnSelector.addEventListener('change', this.onChange)
+    }
+    return dnSelector
   }
 
   private getBlockList(remoteVarKey: StringKeys) {

packages/web/src/services/audius-sdk/discoveryNodeSelector.ts

@@ -3,7 +3,69 @@ import { DiscoveryNodeSelectorService } from '@audius/common'
 import { env } from '../env'
 import { remoteConfigInstance } from '../remote-config/remote-config-instance'
 
+const DISCOVERY_PROVIDER_TIMESTAMP = '@audius/libs:discovery-node-timestamp'
+const CACHE_TTL = 24 * 60 * 1000 // 24 hours
+
+type CachedDiscoveryNodeTimestamp =
+  | {
+      endpoint?: string
+      timestamp?: number
+    }
+  | null
+  | undefined
+
+const getCachedDiscoveryNode = () => {
+  const cached = localStorage.getItem(DISCOVERY_PROVIDER_TIMESTAMP)
+  if (cached) {
+    try {
+      const cachedDiscoveryNodeTimestamp = JSON.parse(
+        cached
+      ) as CachedDiscoveryNodeTimestamp
+      if (
+        cachedDiscoveryNodeTimestamp?.timestamp &&
+        cachedDiscoveryNodeTimestamp.timestamp >
+          new Date().getTime() - CACHE_TTL
+      ) {
+        const cachedDiscoveryNode =
+          cachedDiscoveryNodeTimestamp.endpoint ?? undefined
+        console.debug(
+          '[discovery-node-selector-service] Using cached discovery node',
+          cachedDiscoveryNode
+        )
+        return cachedDiscoveryNode
+      } else {
+        console.debug(
+          '[discovery-node-selector-service] Cached discovery node expired',
+          cachedDiscoveryNodeTimestamp
+        )
+      }
+    } catch (e) {
+      console.error(
+        "[discovery-node-selector-service] Couldn't parse cached discovery node",
+        e
+      )
+    }
+  }
+}
+
+const updateCachedDiscoveryNode = (endpoint: string) => {
+  const newTimestamp: CachedDiscoveryNodeTimestamp = {
+    endpoint,
+    timestamp: new Date().getTime()
+  }
+  console.debug(
+    '[discovery-node-selector-service] Updating cached discovery provider',
+    newTimestamp
+  )
+  localStorage.setItem(
+    DISCOVERY_PROVIDER_TIMESTAMP,
+    JSON.stringify(newTimestamp)
+  )
+}
+
 export const discoveryNodeSelectorService = new DiscoveryNodeSelectorService({
   env,
-  remoteConfigInstance
+  remoteConfigInstance,
+  initialSelectedNode: getCachedDiscoveryNode(),
+  onChange: updateCachedDiscoveryNode
 })