chore: add sync backoff mechanism checks (#2786)

packages/services/src/Domain/Sync/SyncBackoffService.spec.ts

@@ -0,0 +1,55 @@
+import { AnyItemInterface } from '@standardnotes/models'
+import { SyncBackoffService } from './SyncBackoffService'
+
+describe('SyncBackoffService', () => {
+  const createService = () => new SyncBackoffService()
+
+  it('should not be in backoff if no backoff was set', () => {
+    const service = createService()
+
+    expect(service.isItemInBackoff({ uuid: '123' } as jest.Mocked<AnyItemInterface>)).toBe(false)
+  })
+
+  it('should be in backoff if backoff was set', () => {
+    const service = createService()
+
+    service.backoffItem({ uuid: '123' } as jest.Mocked<AnyItemInterface>)
+
+    expect(service.isItemInBackoff({ uuid: '123' } as jest.Mocked<AnyItemInterface>)).toBe(true)
+  })
+
+  it('should not be in backoff if backoff expired', () => {
+    const service = createService()
+
+    jest.spyOn(Date, 'now').mockReturnValueOnce(1_000_000)
+
+    service.backoffItem({ uuid: '123' } as jest.Mocked<AnyItemInterface>)
+
+    jest.spyOn(Date, 'now').mockReturnValueOnce(2_000_000)
+
+    expect(service.isItemInBackoff({ uuid: '123' } as jest.Mocked<AnyItemInterface>)).toBe(false)
+  })
+
+  it('should double backoff penalty on each backoff', () => {
+    const service = createService()
+
+    jest.spyOn(Date, 'now').mockReturnValueOnce(1_000_000)
+
+    service.backoffItem({ uuid: '123' } as jest.Mocked<AnyItemInterface>)
+
+    jest.spyOn(Date, 'now').mockReturnValueOnce(1_000_000)
+    expect(service.isItemInBackoff({ uuid: '123' } as jest.Mocked<AnyItemInterface>)).toBe(true)
+
+    jest.spyOn(Date, 'now').mockReturnValueOnce(1_000_000)
+    service.backoffItem({ uuid: '123' } as jest.Mocked<AnyItemInterface>)
+
+    jest.spyOn(Date, 'now').mockReturnValueOnce(1_001_000)
+    expect(service.isItemInBackoff({ uuid: '123' } as jest.Mocked<AnyItemInterface>)).toBe(true)
+
+    jest.spyOn(Date, 'now').mockReturnValueOnce(1_000_000)
+    service.backoffItem({ uuid: '123' } as jest.Mocked<AnyItemInterface>)
+
+    jest.spyOn(Date, 'now').mockReturnValueOnce(1_003_000)
+    expect(service.isItemInBackoff({ uuid: '123' } as jest.Mocked<AnyItemInterface>)).toBe(true)
+  })
+})

packages/services/src/Domain/Sync/SyncBackoffService.ts

@@ -0,0 +1,37 @@
+import { AnyItemInterface } from '@standardnotes/models'
+import { SyncBackoffServiceInterface } from './SyncBackoffServiceInterface'
+
+export class SyncBackoffService implements SyncBackoffServiceInterface {
+  private backoffPenalties: Map<string, number>
+  private backoffStartTimestamps: Map<string, number>
+
+  constructor() {
+    this.backoffPenalties = new Map<string, number>()
+    this.backoffStartTimestamps = new Map<string, number>()
+  }
+
+  isItemInBackoff(item: AnyItemInterface): boolean {
+    const backoffStartingTimestamp = this.backoffStartTimestamps.get(item.uuid)
+    if (!backoffStartingTimestamp) {
+      return false
+    }
+
+    const backoffPenalty = this.backoffPenalties.get(item.uuid)
+    if (!backoffPenalty) {
+      return false
+    }
+
+    const backoffEndTimestamp = backoffStartingTimestamp + backoffPenalty
+
+    return backoffEndTimestamp > Date.now()
+  }
+
+  backoffItem(item: AnyItemInterface): void {
+    const backoffPenalty = this.backoffPenalties.get(item.uuid) || 0
+
+    const newBackoffPenalty = backoffPenalty === 0 ? 1_000 : backoffPenalty * 2
+
+    this.backoffPenalties.set(item.uuid, newBackoffPenalty)
+    this.backoffStartTimestamps.set(item.uuid, Date.now())
+  }
+}

packages/services/src/Domain/Sync/SyncBackoffServiceInterface.ts

@@ -0,0 +1,6 @@
+import { AnyItemInterface } from '@standardnotes/models'
+
+export interface SyncBackoffServiceInterface {
+  isItemInBackoff(item: AnyItemInterface): boolean
+  backoffItem(item: AnyItemInterface): void
+}

packages/services/src/Domain/index.ts

@@ -181,6 +181,8 @@ export * from './Subscription/AppleIAPReceipt'
 export * from './Subscription/SubscriptionManager'
 export * from './Subscription/SubscriptionManagerEvent'
 export * from './Subscription/SubscriptionManagerInterface'
+export * from './Sync/SyncBackoffService'
+export * from './Sync/SyncBackoffServiceInterface'
 export * from './Sync/SyncMode'
 export * from './Sync/SyncOpStatus'
 export * from './Sync/SyncOptions'

packages/snjs/lib/Application/Dependencies/Dependencies.ts

@@ -145,6 +145,8 @@ import {
   IsVaultAdmin,
   IsReadonlyVaultMember,
   DesignateSurvivor,
+  SyncBackoffService,
+  SyncBackoffServiceInterface,
 } from '@standardnotes/services'
 import { ItemManager } from '../../Services/Items/ItemManager'
 import { PayloadManager } from '../../Services/Payloads/PayloadManager'
@@ -1351,6 +1353,10 @@ export class Dependencies {
       )
     })
 
+    this.factory.set(TYPES.SyncBackoffService, () => {
+      return new SyncBackoffService()
+    })
+
     this.factory.set(TYPES.SyncService, () => {
       return new SyncService(
         this.get<ItemManager>(TYPES.ItemManager),
@@ -1369,6 +1375,7 @@ export class Dependencies {
         this.get<Logger>(TYPES.Logger),
         this.get<WebSocketsService>(TYPES.WebSocketsService),
         this.get<SyncFrequencyGuardInterface>(TYPES.SyncFrequencyGuard),
+        this.get<SyncBackoffServiceInterface>(TYPES.SyncBackoffService),
         this.get<InternalEventBus>(TYPES.InternalEventBus),
       )
     })

packages/snjs/lib/Application/Dependencies/Types.ts

@@ -30,6 +30,7 @@ export const TYPES = {
   SubscriptionManager: Symbol.for('SubscriptionManager'),
   HistoryManager: Symbol.for('HistoryManager'),
   SyncFrequencyGuard: Symbol.for('SyncFrequencyGuard'),
+  SyncBackoffService: Symbol.for('SyncBackoffService'),
   SyncService: Symbol.for('SyncService'),
   ProtectionService: Symbol.for('ProtectionService'),
   UserService: Symbol.for('UserService'),

packages/snjs/lib/Services/Sync/SyncService.ts

@@ -86,6 +86,7 @@ import {
   ApplicationSyncOptions,
   WebSocketsServiceEvent,
   WebSocketsService,
+  SyncBackoffServiceInterface,
 } from '@standardnotes/services'
 import { OfflineSyncResponse } from './Offline/Response'
 import {
@@ -171,6 +172,7 @@ export class SyncService
     private logger: LoggerInterface,
     private sockets: WebSocketsService,
     private syncFrequencyGuard: SyncFrequencyGuardInterface,
+    private syncBackoffService: SyncBackoffServiceInterface,
     protected override internalEventBus: InternalEventBusInterface,
   ) {
     super(internalEventBus)
@@ -452,7 +454,11 @@ export class SyncService
   }
 
   private itemsNeedingSync() {
-    return this.itemManager.getDirtyItems()
+    const dirtyItems = this.itemManager.getDirtyItems()
+
+    const itemsWithoutBackoffPenalty = dirtyItems.filter((item) => !this.syncBackoffService.isItemInBackoff(item))
+
+    return itemsWithoutBackoffPenalty
   }
 
   public async markAllItemsAsNeedingSyncAndPersist(): Promise<void> {