Add segment garbage collection.

src/camera/cache.ts

@@ -103,6 +103,20 @@ export class MemoryRangedCache<Data> {
     }
     return output;
   }
+
+  public size(): number {
+    return this._data.length;
+  }
+
+  /**
+   * Remove old data that matches a given predicate. No change to the covered
+   * ranges is made, i.e. this is asserting authoritiatively that this data does
+   * not exist in the current ranges.
+   * @param predicate A predicate to run on each data element.
+   */
+  public expireMatches(predicate: (data: Data) => boolean): void {
+    this._data = this._data.filter(predicate);
+  }
 }
 
 export class RecordingSegmentsCache {
@@ -128,4 +142,19 @@ export class RecordingSegmentsCache {
   public get(cameraID: string, range: DateRange): RecordingSegment[] | null {
     return this._segments.get(cameraID)?.get(range) ?? null;
   }
+
+  public getCache(cameraID: string): MemoryRangedCache<RecordingSegment> | null {
+    return this._segments.get(cameraID) ?? null;
+  }
+
+  public getCameraIDs(): string[] {
+    return [...this._segments.keys()];
+  }
+
+  public expireMatches(
+    cameraID: string,
+    func: (segment: RecordingSegment) => boolean,
+  ): void {
+    this._segments.get(cameraID)?.expireMatches(func);
+  }
 }

src/camera/frigate/engine-frigate.ts

@@ -1,10 +1,9 @@
 import { HomeAssistant } from 'custom-card-helpers';
 import add from 'date-fns/add';
 import endOfHour from 'date-fns/endOfHour';
-import getUnixTime from 'date-fns/getUnixTime';
 import startOfHour from 'date-fns/startOfHour';
 import { CAMERA_BIRDSEYE } from '../../const';
-import { CameraConfig } from '../../types';
+import { CameraConfig, RecordingSegment } from '../../types';
 import { MediaQueriesResults } from '../../view/media-queries-results';
 import { MediaQueriesClassifier } from '../../view/media-queries-classifier';
 import { ViewMedia, ViewMediaFactory } from '../../view/media';
@@ -42,6 +41,10 @@ import {
 } from './requests';
 import { MediaQueries } from '../../view/media-queries';
 import orderBy from 'lodash-es/orderBy';
+import throttle from 'lodash-es/throttle';
+import { runWhenIdleIfSupported } from '../../utils/basic';
+import { fromUnixTime } from 'date-fns';
+import { sum } from 'lodash-es';
 
 const EVENT_REQUEST_CACHE_MAX_AGE_SECONDS = 60;
 const RECORDING_SUMMARY_REQUEST_CACHE_MAX_AGE_SECONDS = 60;
@@ -74,6 +77,13 @@ class FrigateQueryResultsClassifier {
 export class FrigateCameraManagerEngine implements CameraManagerEngine {
   protected _recordingSegmentsCache: RecordingSegmentsCache;
 
+  // Garbage collect segments at most once an hour.
+  protected _throttledSegmentGarbageCollector = throttle(
+    this._garbageCollectSegments.bind(this),
+    60 * 60 * 1000,
+    { trailing: true },
+  );
+
   constructor(recordingSegmentsCache: RecordingSegmentsCache) {
     this._recordingSegmentsCache = recordingSegmentsCache;
   }
@@ -220,9 +230,9 @@ export class FrigateCameraManagerEngine implements CameraManagerEngine {
           (!query.end || endHour <= query.end)
         ) {
           recordings.push({
-            camera: cameraConfig.frigate.camera_name,
-            start_time: getUnixTime(startHour),
-            end_time: getUnixTime(endHour),
+            cameraID: query.cameraID,
+            startTime: startHour,
+            endTime: endHour,
             events: hourData.events,
           });
         }
@@ -234,7 +244,7 @@ export class FrigateCameraManagerEngine implements CameraManagerEngine {
       // this simulates it.
       recordings = orderBy(
         recordings,
-        (recording: FrigateRecording) => recording.start_time,
+        (recording: FrigateRecording) => recording.startTime,
         'desc',
       ).slice(0, query.limit);
     }
@@ -287,6 +297,8 @@ export class FrigateCameraManagerEngine implements CameraManagerEngine {
     const segments = await getRecordingSegments(hass, request);
     this._recordingSegmentsCache.add(query.cameraID, range, segments);
 
+    runWhenIdleIfSupported(() => this._throttledSegmentGarbageCollector(hass, cameras));
+
     return {
       type: QueryResultsType.RecordingSegments,
       engine: Engine.Frigate,
@@ -381,4 +393,68 @@ export class FrigateCameraManagerEngine implements CameraManagerEngine {
     }
     return cameraConfig;
   }
+
+  /**
+   * Garbage collect recording segments that no longer feature in the recordings
+   * returned by the Frigate backend.
+   */
+  protected async _garbageCollectSegments(
+    hass: HomeAssistant,
+    cameras: Map<string, CameraConfig>,
+  ): Promise<void> {
+    const cameraIDs = this._recordingSegmentsCache.getCameraIDs();
+    const recordingQueries: RecordingQuery[] = cameraIDs.map((cameraID) => ({
+      cameraID: cameraID,
+      type: QueryType.Recording,
+    }));
+
+    const countSegments = () =>
+      sum(
+        cameraIDs.map(
+          (cameraID) => this._recordingSegmentsCache.getCache(cameraID)?.size() ?? 0,
+        ),
+      );
+    const segmentsStart = countSegments();
+
+    const results: Map<RecordingQuery, FrigateRecordingQueryResults> = new Map();
+
+    await Promise.all(
+      recordingQueries.map((query) =>
+        (async () => {
+          const recordings = await this.getRecordings(hass, cameras, query);
+          if (recordings && recordings.engine === Engine.Frigate) {
+            results.set(query, recordings as FrigateRecordingQueryResults);
+          }
+        })(),
+      ),
+    );
+
+    // Performance: _recordingSegments is potentially very large (e.g. 10K - 1M
+    // items) and each item must be examined, so care required here to stick to
+    // nothing worse than O(n) performance.
+    const getHourID = (cameraID: string, startTime: Date): string => {
+      return `${cameraID}/${startTime.getDate()}/${startTime.getHours()}`;
+    };
+
+    for (const [query, result] of results) {
+      const goodHours: Set<string> = new Set();
+      for (const recording of result.recordings) {
+        goodHours.add(getHourID(recording.cameraID, recording.startTime));
+      }
+
+      this._recordingSegmentsCache.expireMatches(
+        query.cameraID,
+        (segment: RecordingSegment) => {
+          const hourID = getHourID(query.cameraID, fromUnixTime(segment.start_time));
+          // ~O(1) lookup time for a JS set.
+          return goodHours.has(hourID);
+        },
+      );
+    }
+
+    console.debug(
+      'Frigate Card recording segment garbage collection: ' +
+        `Released ${segmentsStart - countSegments()} segment(s)`,
+    );
+  }
 }

src/camera/frigate/types.ts

@@ -50,9 +50,8 @@ export const retainResultSchema = z.object({
 export type RetainResult = z.infer<typeof retainResultSchema>;
 
 export interface FrigateRecording {
-  // Frigate camera name (may not be unique)
-  camera: string;
-  start_time: number;
-  end_time: number;
+  cameraID: string;
+  startTime: Date;
+  endTime: Date;
   events: number;
 }

src/view/view.ts

@@ -1,7 +1,7 @@
 // Medium:
-//  - TODO: Add garbage collecting of segments not present in the recording summaries anymore.
 //  - TODO: Move frigate specific view-media under the camera manager.
 //  - TODO: ts-prune https://camchenry.com/blog/deleting-dead-code-in-typescript
+//  - TODO: Use sortedUniqBy in the engine sort/uniq combo.
 
 // Hard:
 //  - TODO: Implement dragging the timeline seeking forward in both Frigate recordings & events.
@@ -85,8 +85,9 @@ export class View {
       !curr ||
       prev.view !== curr.view ||
       prev.camera !== curr.camera ||
-      // When in the live view, the target contains the events that happened in
-      // the past -- not reflective of the actual live media viewer.
+      // When in the live view, the queryResults contain the events that
+      // happened in the past -- not reflective of the actual live media viewer
+      // the user is seeing.
       (curr.view !== 'live' &&
         (prev.queryResults !== curr.queryResults ||
           prev.queryResults?.getSelectedResult() !==
@@ -103,9 +104,6 @@ export class View {
       camera: this.camera,
       query: this.query?.clone() ?? null,
       queryResults: this.queryResults?.clone() ?? null,
-      // target: this.target,
-      // targetIndex: this.targetIndex,
-      // targetFingerprint: this.targetFingerprint,
       context: this.context,
     });
   }