Installation 🤖

Install the nestjs-transaction package with:

npm install @hodfords/nestjs-transaction --save

Usage 🚀

First, you need to import the TransactionModule into your AppModule and

import { Module } from '@nestjs/common';
import { TransactionModule } from '@hodfords/nestjs-transaction';

@Module({
    imports: [
        TransactionModule.forRoot({
            autoUseMasterNodeForChangeRequest: true
        }),
        // other modules
    ],
    controllers: [],
    providers: [],
})
export class AppModule {}

Optional Configuration

You can configure the TransactionModule with the following options:

• autoUseMasterNodeForChangeRequest: If set to true, the module will automatically use the master node for change requests (except GET). This is useful for ensuring that write operations are always directed to the correct database node.

How to use

Transactional

You can use the @Transactional decorator to mark a method as transactional. This means that all database operations within this method and child methods will be executed within a transaction context. If any operation fails, the entire transaction will be rolled back, ensuring data integrity.

In any service, you can use the @Transactional decorator to ensure that the method is executed within a transaction context:

Note: We suggest using the @Transactional decorator on Controller/Task/Cron jobs methods, as it will automatically handle the transaction lifecycle for you. However, you can also use it in services if needed.

@Transactional()
async myTransactionalMethod() {
    await this.myRepository.save(myEntity);
}

In controllers, you can also use the @Transactional decorator to ensure that the entire request is wrapped in a transaction:

import { Controller, Post } from '@nestjs/common';
import { Transactional } from '@hodfords/nestjs-transaction';
import { MyService } from './my.service';

@Controller('my')
export class MyController {
    constructor(private myService: MyService) {}
    
    @Post('create')
    @Transactional()
    async create() {
        return this.myService.create();
    }
}

You also use the @Transactional decorator with options to control the transaction behavior, such as isolation level. For example:

@Transactional({ isolationLevel: 'SERIALIZABLE'})
async myTransactionalMethod() {
    // This method will run in a transaction with SERIALIZABLE isolation level
    await this.myRepository.save(myEntity);
}

Replication

You can use the @UseMasterNode/@UseSlaveNode decorator to ensure that a method is executed on the master/slave node. This is useful for write operations that need to be directed to the master/slave database node.

import { Controller, Post } from '@nestjs/common';
import { UseMasterNode } from '@hodfords/nestjs-transaction';
import { MyService } from './my.service';

@Controller('my')
export class MyController {
    constructor(private myService: MyService) {}
    
    @Post('create')
    @UseMasterNode()
    async create() {
        return this.myService.create();
    }
}

Hooks

You can use the @RunAfterTransactionCommit decorator to run a method after a transaction has been successfully committed. This is useful for performing actions that should only occur if the transaction was successful.

import { Injectable } from '@nestjs/common';
import { RunAfterTransactionCommit } from '@hodfords/nestjs-transaction';
import { PostRepository } from './post.repository';

@Injectable()
export class MyService {

    constructor(private postRepo: PostRepository) {
    }

    @Transactional()
    async create() {
        // Perform some database operations
        await this.postRepo.createPost({ title: 'New Post', content: 'This is a new post.' });
        await this.emitEvent();
    }

    @RunAfterTransactionCommit()
    async emitEvent() {
        // This method will be called after the transaction is committed
        console.log('Transaction committed successfully!');
    }
}

You also use it with method runAfterTransactionCommit without the decorator:

this.postRepo.create(...);
runAfterTransactionCommit(() => {
    // This code will run after the transaction is committed
    console.log('Transaction committed successfully!');
});

License 📝

This project is licensed under the MIT License