feat(server): custom library scanning interval (#4390)

* add automatic library scan config options

* add validation

* open api

* use CronJob instead of cron-validator

* fix tests

* catch potential error of the library scan initialization

* better description for input field

* move library scan job initialization to server app service

* fix tests

* add comments to all parameters of cronjob contructor

* make scan a child of a more general library object

* open api

* chore: cleanup

* move cronjob handling to job repoistory

* web: select for common cron expressions

* fix open api

* fix tests

* put scanning settings in nested accordion

* fix system config validation

* refactor, tests

---------

Co-authored-by: Jason Rasmussen <jrasm91@gmail.com>

server/src/infra/entities/system-config.entity.ts

@@ -94,6 +94,9 @@ export enum SystemConfigKey {
   TRASH_DAYS = 'trash.days',
 
   THEME_CUSTOM_CSS = 'theme.customCss',
+
+  LIBRARY_SCAN_ENABLED = 'library.scan.enabled',
+  LIBRARY_SCAN_CRON_EXPRESSION = 'library.scan.cronExpression',
 }
 
 export enum TranscodePolicy {
@@ -232,4 +235,10 @@ export interface SystemConfig {
   theme: {
     customCss: string;
   };
+  library: {
+    scan: {
+      enabled: boolean;
+      cronExpression: string;
+    };
+  };
 }

server/src/infra/repositories/job.repository.ts

@@ -2,7 +2,9 @@ import { IJobRepository, JobCounts, JobItem, JobName, JOBS_TO_QUEUE, QueueName,
 import { getQueueToken } from '@nestjs/bullmq';
 import { Injectable, Logger } from '@nestjs/common';
 import { ModuleRef } from '@nestjs/core';
+import { SchedulerRegistry } from '@nestjs/schedule';
 import { Job, JobsOptions, Processor, Queue, Worker, WorkerOptions } from 'bullmq';
+import { CronJob, CronTime } from 'cron';
 import { bullConfig } from '../infra.config';
 
 @Injectable()
@@ -10,7 +12,10 @@ export class JobRepository implements IJobRepository {
   private workers: Partial<Record<QueueName, Worker>> = {};
   private logger = new Logger(JobRepository.name);
 
-  constructor(private moduleRef: ModuleRef) {}
+  constructor(
+    private moduleRef: ModuleRef,
+    private schedulerReqistry: SchedulerRegistry,
+  ) {}
 
   addHandler(queueName: QueueName, concurrency: number, handler: (item: JobItem) => Promise<void>) {
     const workerHandler: Processor = async (job: Job) => handler(job as JobItem);
@@ -18,6 +23,43 @@ export class JobRepository implements IJobRepository {
     this.workers[queueName] = new Worker(queueName, workerHandler, workerOptions);
   }
 
+  addCronJob(name: string, expression: string, onTick: () => void, start = true): void {
+    const job = new CronJob(
+      expression,
+      onTick,
+      // function to run onComplete
+      undefined,
+      // whether it should start directly
+      start,
+      // timezone
+      undefined,
+      // context
+      undefined,
+      // runOnInit
+      undefined,
+      // utcOffset
+      undefined,
+      // prevents memory leaking by automatically stopping when the node process finishes
+      true,
+    );
+
+    this.schedulerReqistry.addCronJob(name, job);
+  }
+
+  updateCronJob(name: string, expression?: string, start?: boolean): void {
+    const job = this.schedulerReqistry.getCronJob(name);
+    if (expression) {
+      job.setTime(new CronTime(expression));
+    }
+    if (start !== undefined) {
+      start ? job.start() : job.stop();
+    }
+  }
+
+  deleteCronJob(name: string): void {
+    this.schedulerReqistry.deleteCronJob(name);
+  }
+
   setConcurrency(queueName: QueueName, concurrency: number) {
     const worker = this.workers[queueName];
     if (!worker) {