unleash.unleash/src/lib/services/client-metrics/last-seen-service.ts

import { secondsToMilliseconds } from 'date-fns';
import { Logger } from '../../logger';
import { IUnleashConfig } from '../../server-impl';
import { IUnleashStores } from '../../types';
import { IClientMetricsEnv } from '../../types/stores/client-metrics-store-v2';
import { IFeatureToggleStore } from '../../types/stores/feature-toggle-store';

export class LastSeenService {
    private timers: NodeJS.Timeout[] = [];

    private lastSeenToggles: Set<string> = new Set();

    private logger: Logger;

    private featureToggleStore: IFeatureToggleStore;

    constructor(
        { featureToggleStore }: Pick<IUnleashStores, 'featureToggleStore'>,
        config: IUnleashConfig,
        lastSeenInterval = secondsToMilliseconds(30),
    ) {
        this.featureToggleStore = featureToggleStore;
        this.logger = config.getLogger(
            '/services/client-metrics/last-seen-service.ts',
        );

        this.timers.push(
            setInterval(() => this.store(), lastSeenInterval).unref(),
        );
    }

    async store(): Promise<number> {
        const count = this.lastSeenToggles.size;
        if (count > 0) {
            const lastSeenToggles = [...this.lastSeenToggles];
            this.lastSeenToggles = new Set();
            this.logger.debug(
                `Updating last seen for ${lastSeenToggles.length} toggles`,
            );
            await this.featureToggleStore.setLastSeen(lastSeenToggles);
        }
        return count;
    }

    updateLastSeen(clientMetrics: IClientMetricsEnv[]): void {
        clientMetrics
            .filter(
                (clientMetric) => clientMetric.yes > 0 || clientMetric.no > 0,
            )
            .forEach((clientMetric) =>
                this.lastSeenToggles.add(clientMetric.featureName),
            );
    }

    destroy(): void {
        this.timers.forEach(clearInterval);
    }
}