feat: introduce retention-rate aggregation

packages/backend/src/queue/processors/AggregateRetentionProcessorService.ts

@@ -0,0 +1,75 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { In, IsNull, MoreThan } from 'typeorm';
+import { DI } from '@/di-symbols.js';
+import type { Config } from '@/config.js';
+import type Logger from '@/logger.js';
+import { bindThis } from '@/decorators.js';
+import type { RetentionAggregationsRepository, UsersRepository } from '@/models/index.js';
+import { deepClone } from '@/misc/clone.js';
+import { IdService } from '@/core/IdService.js';
+import { QueueLoggerService } from '../QueueLoggerService.js';
+import type Bull from 'bull';
+
+@Injectable()
+export class AggregateRetentionProcessorService {
+	private logger: Logger;
+
+	constructor(
+		@Inject(DI.config)
+		private config: Config,
+
+		@Inject(DI.usersRepository)
+		private usersRepository: UsersRepository,
+
+		@Inject(DI.retentionAggregationsRepository)
+		private retentionAggregationsRepository: RetentionAggregationsRepository,
+
+		private idService: IdService,
+		private queueLoggerService: QueueLoggerService,
+	) {
+		this.logger = this.queueLoggerService.logger.createSubLogger('aggregate-retention');
+	}
+
+	@bindThis
+	public async process(job: Bull.Job<Record<string, unknown>>, done: () => void): Promise<void> {
+		this.logger.info('Aggregating retention...');
+
+		const now = new Date();
+		const dateKey = `${now.getFullYear()}-${now.getMonth() + 1}-${now.getDate()}`;
+
+		// 過去(だいたい)30日分のレコードを取得
+		const pastRecords = await this.retentionAggregationsRepository.findBy({
+			createdAt: MoreThan(new Date(Date.now() - (1000 * 60 * 60 * 24 * 31))),
+		});
+
+		// 今日登録したユーザーを全て取得
+		const targetUsers = await this.usersRepository.findBy({
+			host: IsNull(),
+			createdAt: MoreThan(new Date(Date.now() - (1000 * 60 * 60 * 24))),
+		});
+		const targetUserIds = targetUsers.map(u => u.id);
+
+		await this.retentionAggregationsRepository.insert({
+			id: this.idService.genId(),
+			createdAt: now,
+			updatedAt: now,
+			userIds: targetUserIds,
+			usersCount: targetUserIds.length,
+		});
+
+		for (const record of pastRecords) {
+			const retention = record.userIds.filter(id => targetUserIds.includes(id)).length;
+
+			const data = deepClone(record.data);
+			data[dateKey] = retention;
+
+			this.retentionAggregationsRepository.update(record.id, {
+				updatedAt: now,
+				data,
+			});
+		}
+
+		this.logger.succ('Retention aggregated.');
+		done();
+	}
+}