feat(store): add debounce/throttle option

allow to use debounce/throttle when updating stores if there are 15 events in a row to update a store, it can be updated only once after all events completed in like 1.5s related to podman-desktop#3376 Signed-off-by: Florent Benoit <[email protected]>
benoitf · Aug 14, 2023 · 76948ac · 76948ac
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diff --git a/packages/renderer/src/stores/containers.ts b/packages/renderer/src/stores/containers.ts
@@ -62,7 +62,7 @@ const containersEventStore = new EventStore<ContainerInfo[]>(
   listContainers,
   ContainerIcon,
 );
-containersEventStore.setup();
+containersEventStore.setupWithDebounce();
 
 export const searchPattern = writable('');
 

diff --git a/packages/renderer/src/stores/event-store.spec.ts b/packages/renderer/src/stores/event-store.spec.ts
@@ -155,3 +155,120 @@ test('should call fetch method using listener event', async () => {
   expect(eventStoreInfo.bufferEvents[0]).toHaveProperty('args', undefined);
   expect(eventStoreInfo.bufferEvents[0]).toHaveProperty('length', 1);
 });
+
+test('Check debounce', async () => {
+  const myStoreInfo: Writable<MyCustomTypeInfo[]> = writable([]);
+  const checkForUpdateMock = vi.fn();
+
+  const windowEventName = 'my-custom-event';
+  const updater = vi.fn();
+
+  // return true to trigger the update
+  checkForUpdateMock.mockResolvedValue(true);
+
+  const eventStore = new EventStore('my-test', myStoreInfo, checkForUpdateMock, [windowEventName], [], updater);
+
+  // callbacks are empty
+  expect(callbacks.size).toBe(0);
+
+  // now call the setup with a debounce value of 200ms and no throttle
+  const eventStoreInfo = eventStore.setupWithDebounce(200, 0);
+
+  // check we have callbacks
+  expect(callbacks.size).toBe(1);
+
+  // now we call the listener
+  const callback = callbacks.get(windowEventName);
+  expect(callback).toBeDefined();
+
+  const myCustomTypeInfo: MyCustomTypeInfo = {
+    name: 'my-custom-type',
+  };
+  updater.mockResolvedValue([myCustomTypeInfo]);
+
+  // now, perform 20 calls every 50ms
+  for (let i = 0; i < 20; i++) {
+    await callback();
+    await new Promise(resolve => setTimeout(resolve, 50));
+  }
+
+  // wait debounce being called for 2 seconds
+  await new Promise(resolve => setTimeout(resolve, 2000));
+
+  // We did a lot of calls but with debounce, it should only be called once
+  expect(updater).toHaveBeenCalledOnce();
+
+  // check the store is updated
+  expect(get(myStoreInfo)).toStrictEqual([myCustomTypeInfo]);
+
+  // check the store is updated
+  expect(get(myStoreInfo)).toStrictEqual([myCustomTypeInfo]);
+
+  // check buffer events
+  expect(eventStoreInfo.bufferEvents.length).toBe(1);
+  expect(eventStoreInfo.bufferEvents[0]).toHaveProperty('name', windowEventName);
+  expect(eventStoreInfo.bufferEvents[0]).toHaveProperty('skipped', false);
+  expect(eventStoreInfo.bufferEvents[0]).toHaveProperty('args', undefined);
+  expect(eventStoreInfo.bufferEvents[0]).toHaveProperty('length', 1);
+});
+
+// check that we're still calling the update method
+// every throttle even if we have lot of calls and are postponing with debounce
+test('Check debounce+delay', async () => {
+  const myStoreInfo: Writable<MyCustomTypeInfo[]> = writable([]);
+  const checkForUpdateMock = vi.fn();
+
+  const windowEventName = 'my-custom-event';
+  const updater = vi.fn();
+
+  // return true to trigger the update
+  checkForUpdateMock.mockResolvedValue(true);
+
+  const eventStore = new EventStore('my-test', myStoreInfo, checkForUpdateMock, [windowEventName], [], updater);
+
+  // callbacks are empty
+  expect(callbacks.size).toBe(0);
+
+  // now call the setup with a debounce value of 200ms and a throttle of 1s
+  const eventStoreInfo = eventStore.setupWithDebounce(200, 1000);
+
+  // check we have callbacks
+  expect(callbacks.size).toBe(1);
+
+  // now we call the listener
+  const callback = callbacks.get(windowEventName);
+  expect(callback).toBeDefined();
+
+  const myCustomTypeInfo: MyCustomTypeInfo = {
+    name: 'my-custom-type',
+  };
+  updater.mockResolvedValue([myCustomTypeInfo]);
+
+  // now, perform 40 calls every 50ms
+  for (let i = 0; i < 20; i++) {
+    await callback();
+    await new Promise(resolve => setTimeout(resolve, 50));
+  }
+
+  // wait debounce being called for 3 seconds
+  await new Promise(resolve => setTimeout(resolve, 3000));
+
+  // We did a lot of calls but with debounce and throttle it should be only like 2 calls
+  // get number of calls
+  const calls = updater.mock.calls.length;
+  expect(calls).toBeGreaterThan(1);
+  expect(calls).toBeLessThanOrEqual(4);
+
+  // check the store is updated
+  expect(get(myStoreInfo)).toStrictEqual([myCustomTypeInfo]);
+
+  // check the store is updated
+  expect(get(myStoreInfo)).toStrictEqual([myCustomTypeInfo]);
+
+  // check buffer events
+  expect(eventStoreInfo.bufferEvents.length).toBeGreaterThan(1);
+  expect(eventStoreInfo.bufferEvents[0]).toHaveProperty('name', windowEventName);
+  expect(eventStoreInfo.bufferEvents[0]).toHaveProperty('skipped', false);
+  expect(eventStoreInfo.bufferEvents[0]).toHaveProperty('args', undefined);
+  expect(eventStoreInfo.bufferEvents[0]).toHaveProperty('length', 1);
+});
diff --git a/packages/renderer/src/stores/event-store.ts b/packages/renderer/src/stores/event-store.ts
@@ -25,26 +25,33 @@ import { addStore, updateStore } from './event-store-manager';
 import humanizeDuration from 'humanize-duration';
 import DesktopIcon from '../lib/images/DesktopIcon.svelte';
 
-export interface EventStoreInfo {
+// 1.5 SECOND for DEBOUNCE and 5s for THROTTLE
+const SECOND = 1000;
+const DEFAULT_DEBOUNCE_TIMEOUT = 1.5 * SECOND;
+const DEFAULT_THROTTLE_TIMEOUT = 5 * SECOND;
+
+interface EventStoreInfoEvent {
   name: string;
 
-  iconComponent?: ComponentType;
+  // args of the event
+  args: unknown[];
 
-  // list last 100 events
-  bufferEvents: {
-    name: string;
+  date: number;
+  // if the event was skipped
+  skipped: boolean;
+  length?: number;
 
-    // args of the event
-    args: unknown[];
+  // update time in ms
+  humanDuration?: number;
+}
 
-    date: number;
-    // if the event was skipped
-    skipped: boolean;
-    length?: number;
+export interface EventStoreInfo {
+  name: string;
 
-    // update time in ms
-    humanDuration?: number;
-  }[];
+  iconComponent?: ComponentType;
+
+  // list last 100 events
+  bufferEvents: EventStoreInfoEvent[];
 
   // number of elements in the store
   size: number;
@@ -59,6 +66,14 @@ export interface EventStoreInfo {
 // Helper to manage store updated from events
 
 export class EventStore<T> {
+  // debounce delay in ms. If set to > 0 , timeout before updating store value
+  // if there are always new requests, it will never update the store
+  // as we postpone the update until there is no new request
+  private debounceTimeoutDelay = 0;
+
+  // debounce always delay in ms. If set to > 0 , update after this delay even if some requests are pending.
+  private debounceThrottleTimeoutDelay = 0;
+
   constructor(
     private name: string,
     private store: Writable<T>,
@@ -73,6 +88,15 @@ export class EventStore<T> {
     }
   }
 
+  protected updateEvent(eventStoreInfo: EventStoreInfo, event: EventStoreInfoEvent) {
+    // update the info object
+    eventStoreInfo.bufferEvents.push(event);
+    if (eventStoreInfo.bufferEvents.length > 100) {
+      eventStoreInfo.bufferEvents.shift();
+    }
+    updateStore(eventStoreInfo);
+  }
+
   protected async performUpdate(
     needUpdate: boolean,
     eventStoreInfo: EventStoreInfo,
@@ -100,22 +124,26 @@ export class EventStore<T> {
         this.store.set(result);
       }
     } finally {
-      // update the info object
-      eventStoreInfo.bufferEvents.push({
+      this.updateEvent(eventStoreInfo, {
         name: eventName,
         args: args,
         date: Date.now(),
         skipped: !needUpdate,
         length: numberOfResults,
         humanDuration: updateDuration,
       });
-      if (eventStoreInfo.bufferEvents.length > 100) {
-        eventStoreInfo.bufferEvents.shift();
-      }
-      updateStore(eventStoreInfo);
     }
   }
 
+  setupWithDebounce(
+    debounceTimeoutDelay = DEFAULT_DEBOUNCE_TIMEOUT,
+    debounceThrottleTimeoutDelay = DEFAULT_THROTTLE_TIMEOUT,
+  ): EventStoreInfo {
+    this.debounceTimeoutDelay = debounceTimeoutDelay;
+    this.debounceThrottleTimeoutDelay = debounceThrottleTimeoutDelay;
+    return this.setup();
+  }
+
   setup(): EventStoreInfo {
     const bufferEvents = [];
 
@@ -136,10 +164,74 @@ export class EventStore<T> {
     };
     addStore(eventStoreInfo);
 
+    // for debounce
+    let timeout: NodeJS.Timeout | undefined;
+    let timeoutEventName: string | undefined;
+
+    // for throttling every 5s if not already done
+    let timeoutThrottle: NodeJS.Timeout | undefined;
+
     const update = async (eventName: string, args?: unknown[]) => {
-      const needUpdate = await this.checkForUpdate(eventName, args);
-      await this.performUpdate(needUpdate, eventStoreInfo, eventName, args);
+      // method that do the update
+      const doUpdate = async () => {
+        const needUpdate = await this.checkForUpdate(eventName, args);
+        await this.performUpdate(needUpdate, eventStoreInfo, eventName, args);
+      };
+
+      // no debounce, just do it
+      if (this.debounceTimeoutDelay <= 0) {
+        await doUpdate();
+        return;
+      }
+
+      // debounce timeout. If there is a pending action, cancel it and wait longer
+      if (timeout) {
+        clearTimeout(timeout);
+
+        this.updateEvent(eventStoreInfo, {
+          name: `debounce-${timeoutEventName}`,
+          args: args,
+          date: Date.now(),
+          skipped: true,
+          length: 0,
+          humanDuration: 0,
+        });
+
+        timeout = undefined;
+        timeoutEventName = eventName;
+      }
+      timeout = setTimeout(() => {
+        // cancel the throttleTimeout if any
+        if (timeoutThrottle) {
+          clearTimeout(timeoutThrottle);
+          timeoutThrottle = undefined;
+        }
+
+        doUpdate()
+          .catch((error: unknown) => {
+            console.error(`Failed to update ${this.name}`, error);
+          })
+          .finally(() => {
+            timeout = undefined;
+          });
+      }, this.debounceTimeoutDelay);
+
+      // throttle timeout, ask after 5s to update anyway to have at least UI being refreshed every 5s if there is a lot of events
+      // because debounce will defer all the events until the end so it's not so nice from UI side.
+      if (!timeoutThrottle && this.debounceThrottleTimeoutDelay > 0) {
+        timeoutThrottle = setTimeout(() => {
+          doUpdate()
+            .catch((error: unknown) => {
+              console.error(`Failed to update ${this.name}`, error);
+            })
+            .finally(() => {
+              clearTimeout(timeoutThrottle);
+              timeoutThrottle = undefined;
+            });
+        }, this.debounceThrottleTimeoutDelay);
+      }
     };
+
     this.windowEvents.forEach(eventName => {
       window.events?.receive(eventName, async (args?: unknown[]) => {
         await update(eventName, args);

diff --git a/packages/renderer/src/stores/images.ts b/packages/renderer/src/stores/images.ts
@@ -65,7 +65,7 @@ const imagesEventStore = new EventStore<ImageInfo[]>(
   listImages,
   ImageIcon,
 );
-imagesEventStore.setup();
+imagesEventStore.setupWithDebounce();
 
 export const searchPattern = writable('');
 

diff --git a/packages/renderer/src/stores/pods.ts b/packages/renderer/src/stores/pods.ts
@@ -64,7 +64,7 @@ const eventStore = new EventStore<PodInfo[]>(
   grabAllPods,
   PodIcon,
 );
-eventStore.setup();
+eventStore.setupWithDebounce();
 
 export async function grabAllPods(): Promise<PodInfo[]> {
   let result = await window.listPods();

diff --git a/packages/renderer/src/stores/volumes.ts b/packages/renderer/src/stores/volumes.ts
@@ -65,7 +65,7 @@ export const volumesEventStore = new EventStore<VolumeListInfo[]>(
   listVolumes,
   VolumeIcon,
 );
-const volumesEventStoreInfo = volumesEventStore.setup();
+const volumesEventStoreInfo = volumesEventStore.setupWithDebounce();
 
 export const searchPattern = writable('');