feat: debounce write to disk

Author: KatoakDR

electron/main/cache/__tests__/disk-cache-service.test.ts

@@ -1,6 +1,9 @@
 import * as fs from 'fs-extra';
 import { DiskCacheServiceImpl } from '../disk-cache.service';
 
+// To quickly skip past the debounced write to disk time.
+jest.useFakeTimers();
+
 describe('disk-cache-service', () => {
   const filepath = '/tmp/dsa2d';
 
@@ -10,6 +13,8 @@ describe('disk-cache-service', () => {
 
   afterEach(() => {
     fs.removeSync(filepath);
+    jest.clearAllMocks();
+    jest.clearAllTimers();
   });
 
   test('set - primitive', async () => {
@@ -21,6 +26,8 @@ describe('disk-cache-service', () => {
 
     await cacheService.set('key', 42);
 
+    await jest.advanceTimersToNextTimerAsync();
+
     const cacheAfter = await fs.readJson(filepath);
 
     expect(cacheBefore.key).toEqual(undefined);
@@ -36,6 +43,8 @@ describe('disk-cache-service', () => {
 
     await cacheService.set('key', { value: 42 });
 
+    await jest.advanceTimersToNextTimerAsync();
+
     const cacheAfter = await fs.readJson(filepath);
 
     expect(cacheBefore.key).toEqual(undefined);
@@ -87,6 +96,8 @@ describe('disk-cache-service', () => {
 
     await cacheService.remove('key');
 
+    await jest.advanceTimersToNextTimerAsync();
+
     const cacheAfter = await fs.readJson(filepath);
 
     expect(cacheBefore.key).toEqual(42);
@@ -104,6 +115,8 @@ describe('disk-cache-service', () => {
 
     await cacheService.remove('key');
 
+    await jest.advanceTimersToNextTimerAsync();
+
     const cacheAfter = await fs.readJson(filepath);
 
     expect(cacheBefore.key).toEqual({ value: 42 });
@@ -119,6 +132,8 @@ describe('disk-cache-service', () => {
 
     await cacheService.remove('non-existant-key');
 
+    await jest.advanceTimersToNextTimerAsync();
+
     const cacheAfter = await fs.readJson(filepath);
 
     expect(cacheBefore.key).toEqual(undefined);
@@ -136,6 +151,8 @@ describe('disk-cache-service', () => {
 
     await cacheService.clear();
 
+    await jest.advanceTimersToNextTimerAsync();
+
     const cacheAfter = await fs.readJson(filepath);
 
     expect(cacheBefore).toEqual({ key: { value: 42 } });

electron/main/cache/disk-cache.service.ts

@@ -1,4 +1,6 @@
 import * as fs from 'fs-extra';
+import type { DebouncedFunc } from 'lodash';
+import { debounce } from 'lodash';
 import type { Maybe } from '../../common/types';
 import { createLogger } from '../logger';
 import { AbstractCacheService } from './abstract-cache.service';
@@ -19,9 +21,15 @@ export class DiskCacheServiceImpl extends AbstractCacheService {
    */
   private delegate: CacheService;
 
+  /**
+   * Debounce writes to disk for performance.
+   */
+  private writeToDisk: DebouncedFunc<() => Promise<void>>;
+
   constructor(private options: DiskCacheOptions) {
     super();
     this.delegate = this.createCacheServiceFromDisk();
+    this.writeToDisk = this.createDebouncedWriteToDisk();
   }
 
   private createCacheServiceFromDisk(): CacheService {
@@ -44,6 +52,21 @@ export class DiskCacheServiceImpl extends AbstractCacheService {
     return new MemoryCacheServiceImpl(cache);
   }
 
+  private createDebouncedWriteToDisk(): DebouncedFunc<() => Promise<void>> {
+    return debounce(async () => {
+      const { filepath } = this.options;
+      try {
+        const cache = await this.delegate.readCache();
+        await fs.writeJson(filepath, cache);
+      } catch (error) {
+        logger.error('error writing cache to disk', {
+          filepath,
+          error,
+        });
+      }
+    }, 1000);
+  }
+
   public async set<T>(key: string, item: T): Promise<void> {
     await this.delegate.set(key, item);
     await this.writeToDisk();
@@ -66,18 +89,4 @@ export class DiskCacheServiceImpl extends AbstractCacheService {
   public async readCache(): Promise<Cache> {
     return this.delegate.readCache();
   }
-
-  protected async writeToDisk(): Promise<void> {
-    const { filepath } = this.options;
-
-    try {
-      const cache = await this.delegate.readCache();
-      await fs.writeJson(filepath, cache);
-    } catch (error) {
-      logger.error('error writing cache to disk', {
-        filepath,
-        error,
-      });
-    }
-  }
 }