nest-cron-manager

Overview

This project, nest-cron-manager, is a TypeScript-based library designed to manage and execute cron jobs efficiently within a NestJS application. It provides a robust interface for scheduling, executing, and logging cron jobs, with support for Redis-based locking mechanisms to ensure job execution integrity. The library leverages ORM frameworks like TypeORM or Mongoose for database operations and is designed to be extensible, allowing for easy integration with other ORMs in the future. It integrates seamlessly with NestJS's dependency injection system.

Installation

To install, use:

npm install nest-cron-manager

# or

yarn add nest-cron-manager

Getting Started

Please see the repository for examples of how to use the library.

Prerequisites

Before using the nest-cron-manager library, ensure the following requirements are met:

• Install ioredis, @nestjs/config, @nestjs/schedule

• Install typeorm, @nestjs/typeorm, pg or @nestjs/mongoose, mongoose depending on the ORM you are using.

  npm install ioredis typeorm @nestjs/config @nestjs/schedule @nestjs/typeorm pg

• Create CronConfig and CronJob models in your project which implement the CronConfigInterface and CronJobInterface respectively.

  // src/cron-manager/cron-config.model.ts
  
  import { CronManager } from 'nest-cron-manager';
  import {
    CronConfig as CronConfigInterface,
    CronJob as CronJobInterface,
  } from 'nest-cron-manager/types';
  import { Column, Entity, OneToMany, PrimaryGeneratedColumn } from 'typeorm';
  import { CronJob } from './cron-job.model';
  
  @Entity({ name: 'cron_configs' })
  export class CronConfig implements CronConfigInterface {
    @PrimaryGeneratedColumn()
    id: number;
  
    @Column({ unique: true })
    name: string;
  
    @Column({ nullable: true, default: CronManager.JobType.INLINE })
    jobType?: string;
  
    @Column({ default: false })
    enabled: boolean;
  
    @Column({ nullable: true, type: 'jsonb' })
    context?: any;
  
    @Column({ nullable: true })
    cronExpression?: string;
  
    @Column({ nullable: true })
    query?: string;
  
    @Column({ nullable: true, default: false })
    dryRun?: boolean;
  
    @Column({ nullable: true })
    deletedAt?: Date;
  
    @OneToMany(() => CronJob, (cronJob) => cronJob.config)
    jobs: CronJobInterface[];
  }

  // src/cron-manager/cron-job.model.ts
  
  import { Column, Entity, Index, ManyToOne, PrimaryGeneratedColumn } from 'typeorm';
  import { CronConfig } from './cron-config.model';
  import { CronJob as CronJobInterface } from 'nest-cron-manager/types';
  
  @Entity({ name: 'cron_jobs' })
  export class CronJob implements CronJobInterface {
    @PrimaryGeneratedColumn()
    id: number;
  
    @Index()
    @ManyToOne(() => CronConfig, (config) => config.jobs)
    config: CronJobInterface;
  
    @Column({ nullable: true, type: 'jsonb' })
    result?: any;
  
    @Column()
    startedAt: Date;
  
    @Column({ nullable: true })
    completedAt: Date;
  
    @Column({ nullable: true })
    failedAt: Date;
  }

• NB: You can implement whatever network and serialization protocol you want to use. For the purpose of this example, we will use gRPC.

• Create these protobuf service definitions: CreateCronConfig and UpdateCronConfig in your project.

  syntax = "proto3";
  
  package cron;
  
  service InventoryService {
    /**
    * Create new inventory cron config. Cron config name must match the function name
    */
    rpc CreateCronConfig(cron.CreateCronConfigRequest) returns (cron.CreateCronConfigResponse) {
        option (google.api.http) = {
            post: "/v1/inventory/cron-config"
            body: "*"
        };
    };
  
    /**
    * Update inventory cron config. Cron config name must match the function name
    */
    rpc UpdateCronConfig(cron.UpdateCronConfigRequest) returns (cron.UpdateCronConfigResponse) {
        option (google.api.http) = {
            put: "/v1/inventory/cron-config/{id}"
            body: "*"
        };
    };
  }
  

• Create a CronConfigController in your project to handle the creation and updating of cron configurations.

  // src/cron-manager/cron-config.controller.ts
  
  import { CronManager } from 'nest-cron-manager';
  import { Controller } from '@nestjs/common';
  import { GrpcMethod } from '@nestjs/microservices';
  import {
    CreateCronConfigRequest,
    UpdateCronConfigRequest,
  } from '../../generated_ts_proto/inventory/inventory_pb';
  
  @Controller()
  export class CronConfigController {
    constructor(private readonly cronManager: CronManager) {}
  
    @GrpcMethod('InventoryService', 'CreateCronConfig')
    async createCronConfig(data: CreateCronConfigRequest.AsObject) {
      return this.cronManager.createCronConfig(data);
    }
  
    @GrpcMethod('InventoryService', 'UpdateCronConfig')
    async updateCronConfig(data: UpdateCronConfigRequest.AsObject) {
      return this.cronManager.updateCronConfig(data);
    }
  
    // You have the flexibility to add additional methods/controllers as needed. 
    // The underlying data tables and their records are fully under your control, allowing you to interact with them as you see fit.
    // However, the shcemas must continue to conform to the CronConfigInterface` and `CronJobInterface`.
  }

• Create a CacheService in your project and ensure it implements a getClient method.

  import { Injectable, OnModuleDestroy } from '@nestjs/common';
  import { ConfigService } from '@nestjs/config';
  import Redis from 'ioredis';
  
  @Injectable()
  export class CacheService implements OnModuleDestroy {
    private client: Redis;
  
    constructor(private readonly config: ConfigService) {
      this.client = new Redis(this.config.get('app.redisUrl'));
    }
  
    async onModuleDestroy() {
      await this.client.quit();
    }
  
    getClient(): Redis {
      return this.client;
    }
  }

• Implement nestjs config service in your project. See the nestjs config documentation for more information.

  import { registerAs } from '@nestjs/config';
  
  export default registerAs('app', () => ({
    redisUrl: process.env.REDIS_URL,
    cronManager: {
      enabled: process.env.CRON_MANAGER_ENABLED,
      querySecret: process.env.CRON_MANAGER_QUERY_SECRET,
    },
  }));

Instantiating the CronManager class

Create an instance of CronManager by passing the required dependencies specified in CronManagerDeps:

// src/cron-manager/cron-manager.module.ts

import { CacheModule } from '@/cache/cache.module';
import { CacheService } from '@/cache/cache.service';
import { Logger, Module } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { getEntityManagerToken, getRepositoryToken, TypeOrmModule } from '@nestjs/typeorm';
import { CronManager } from 'nest-cron-manager';
import { EntityManager, Repository } from 'typeorm';
import { CronConfigController } from './cron-config.controller';
import { CronConfig } from './cron-config.model';
import { CronJob } from './cron-job.model';
import { CronJobService } from './cron-job.service';
import { ProductModule } from './product/product.module';

@Module({
  controllers: [CronConfigController],
  imports: [
    CacheModule,
    TypeOrmModule.forFeature([CronConfig, CronJob]),
    // Be mindful of circular dependencies for modules
    // which import the CronMangerModule
    forwardRef(() => ProductModule),
  ],
  providers: [
    CronJobService,
    {
      provide: CronManager,
      useFactory: async (
        cronConfigRepository: Repository<CronConfig>,
        cronJobRepository: Repository<CronJob>,
        configService: ConfigService,
        redisService: CacheService,
        cronJobService: CronJobService,
        entityManager: EntityManager,
      ) =>
        new CronManager({
          logger: new Logger(CronManager.name),
          configService,
          cronConfigRepository,
          cronJobRepository,
          redisService,
          cronJobService,
          entityManager,
          ormType: 'typeorm',
        }),
      inject: [
        getRepositoryToken(CronConfig),
        getRepositoryToken(CronJob),
        ConfigService,
        CacheService,
        CronJobService,
        getEntityManagerToken(),
      ],
    },
  ],
  exports: [CronManager],
})
export class CronMangerModule {}

CronManager Dependencies

Executing cron jobs

Depending on the specified jobType when creating your cronConfig, there are different ways the nest-cron-manager may execute a job:

1. inline:

Simply pass the cronConfig name and a callback function as first and second arguments respectively to the handleJob method of the CronManager class. The callback function will be executed at the specified cron interval.

curl -X 'POST' \
  'https://server.com/v1/inventory/cron-config' \
  -H 'accept: application/json' \
  -H 'Content-Type: application/json' \
  -d '{
  "name": "doSomething",
  "jobType": "inline",
  "enabled": true,
  "context": "{
    \"distributed\": true,
    \"ttl\": 20,
    \"[key]\":\"value\"
  }"
}'

The context field is optional and can be used to pass additional configuration to the cron job.

In this example, we are passing a distributed flag to indicate that the job should be distributed across multiple instances of the application.

We are also passing a ttl field to specify the time to live for the job lock in seconds.

Asides the distributed and ttl fields which are used internally, you can pass any other configuration you want to the cron job which can be accessed in the job handler.

NB: The context field must be a valid JSON string.

You can access a lens object which is an instance of the Lens class to capture logs and metrics for the job.

import { CronManager } from 'nest-cron-manager';
import { Cron, CronExpression } from '@nestjs/schedule';
import { Injectable } from '@nestjs/common';
import { Lens } from 'nest-cron-manager/types';

@Injectable()
export class SomeService {
  constructor(private readonly cronManager: CronManager) {}

  @Cron(CronExpression.EVERY_5_MINUTES)
  async doSomething() {
    await this.cronManager.handleJob(
      'doSomething',
      async (context: Record<string, any>, config: Record<string, any>, lens: Lens) => {
        // Variables here

        // Perform an operation

        // Capture logs and metrics
        lens.capture({
          title: 'Operation 1',
          message: 'Operation 1 successful',
        });

        // Perform another operation

        // Capture logs and metrics
        lens.capture({
          title: 'Operation 2',
          message: 'Operation 2 successful',
          total: 5,
          // Add any other data you want to capture
        });

        // If an error is thrown, the job will be marked as failed
        // throw new Error('your error message');
      },
    );
  }
}

2. query:

The nest-cron-manager will execute a valid sql query if you create a CronConfig with the jobType set to query, and a valid cronExpression specified. The query will be encrypted at rest using the querySecret from the configService. During runtime, the same querySecret will be used to decrypt the query for execution.

curl -X 'POST' \
  'https://server.com/v1/inventory/cron-config' \
  -H 'accept: application/json' \
  -H 'Content-Type: application/json' \
  -d '{
  "name": "doSomething",
  "jobType": "query",
  "enabled": false,
  "query": "SELECT * FROM inventory",
}'

3. method:

The nest-cron-manager will execute methods defined on your CronJobService class if you create a CronConfig with the jobType set to method, and a valid cronExpression provided. The nest-cron-manager identifies the method to execute by matching the CronConfig name with the method name so ensure they match.

curl -X 'POST' \
  'https://server.com/v1/inventory/cron-config' \
  -H 'accept: application/json' \
  -H 'Content-Type: application/json' \
  -d '{
  "name": "doSomething",
  "jobType": "method",
  "enabled": false,
  "cronExpression": "0 0 * * *",
}'

Below is an example of how you may define your method on a CronJobService class:

import { Injectable } from '@nestjs/common';
import { bindMethods } from 'nest-cron-manager';

@Injectable()
export class CronJobService {
  constructor() {}

  onModuleInit() {
    // This is important to ensure that the `this` context is preserved
    bindMethods(this);
  }

  async doSomething() {
    // Perform some operation
  }
}

Congratulations! You have successfully set up the nest-cron-manager library in your NestJS application. With this powerful tool, you can now manage your cron jobs with ease and confidence. The library provides you with the ability to enable or disable individual cron jobs or even all jobs at once, giving you full control over your scheduled tasks. This ensures that your cron jobs run as expected, improving the reliability and maintainability of your application.

By integrating nest-cron-manager, you have taken a significant step towards automating and optimizing your application's background processes. Whether you need to schedule regular data backups, send periodic notifications, or perform routine maintenance tasks, this library has you covered.

Thank you for using nest-cron-manager. I hope it enhances your development experience and helps you achieve your project goals. Stay tuned for more because they sure are coming!

License

This project is licensed under the MIT License - see the LICENSE file for details.