Typeorm Transactional
A Transactional
Method Decorator for typeorm that uses ALS or cls-hooked to handle and propagate transactions between different repositories and service methods.
See Changelog
Installation
#
npm install --save typeorm-transactional
#
npm install --save typeorm reflect-metadata
Or
yarn add typeorm-transactional
#
yarn add typeorm reflect-metadata
Note: You will need to import reflect-metadata
somewhere in the global place of your app - https://github.com/typeorm/typeorm#installation
Initialization
In order to use it, you will first need to initialize the transactional context before your application is started
import { initializeTransactionalContext } from 'typeorm-transactional';
initializeTransactionalContext()
...
app = express()
...
IMPORTANT NOTE
Calling initializeTransactionalContext must happen BEFORE any application context is initialized!
Usage
New versions of TypeORM use DataSource
instead of Connection
, so most of the API has been changed and the old API has become deprecated.
To be able to use TypeORM entities in transactions, you must first add a DataSource using the addTransactionalDataSource
function:
import { DataSource } from 'typeorm';
import { initializeTransactionalContext, addTransactionalDataSource, StorageDriver } from 'typeorm-transactional';
...
const dataSource = new DataSource({
type: 'postgres',
host: 'localhost',
port: 5435,
username: 'postgres',
password: 'postgres'
});
...
initializeTransactionalContext({ storageDriver: StorageDriver.ASYNC_LOCAL_STORAGE });
addTransactionalDataSource(dataSource);
...
Example for Nest.js
:
import { NestFactory } from '@nestjs/core';
import { initializeTransactionalContext } from 'typeorm-transactional';
import { AppModule } from './app';
const bootstrap = async () => {
initializeTransactionalContext();
const app = await NestFactory.create(AppModule, {
abortOnError: true,
});
await app.listen(3000);
};
bootstrap();
import { Module } from '@nestjs/common';
import { TypeOrmModule } from '@nestjs/typeorm';
import { DataSource } from 'typeorm';
import { addTransactionalDataSource } from 'typeorm-transactional';
@Module({
imports: [
TypeOrmModule.forRootAsync({
useFactory() {
return {
type: 'postgres',
host: 'localhost',
port: 5435,
username: 'postgres',
password: 'postgres',
synchronize: true,
logging: false,
};
},
async dataSourceFactory(options) {
if (!options) {
throw new Error('Invalid options passed');
}
return addTransactionalDataSource(new DataSource(options));
},
}),
...
],
providers: [...],
exports: [...],
})
class AppModule {}
Unlike typeorm-transactional-cls-hooked
, you do not need to use BaseRepository
or otherwise define repositories.
You can also use this library with custom TypeORM repositories. You can read more about them here and here.
NOTE: You can add multiple DataSource
if you need it
Using Transactional Decorator
- Every service method that needs to be transactional, need to use the
@Transactional()
decorator - The decorator can take a
connectionName
as argument (by default it is default
) to specify the data source to be user - The decorator can take an optional
propagation
as argument to define the propagation behaviour - The decorator can take an optional
isolationLevel
as argument to define the isolation level (by default it will use your database driver's default isolation level)
export class PostService {
constructor(readonly repository: PostRepository)
@Transactional()
async createPost(id, message): Promise<Post> {
const post = this.repository.create({ id, message })
return this.repository.save(post)
}
}
You can also use DataSource
/EntityManager
objects together with repositories in transactions:
export class PostService {
constructor(readonly repository: PostRepository, readonly dataSource: DataSource)
@Transactional()
async createAndGetPost(id, message): Promise<Post> {
const post = this.repository.create({ id, message })
await this.repository.save(post)
return dataSource.createQueryBuilder(Post, 'p').where('id = :id', id).getOne();
}
}
Data Sources
In new versions of TypeORM
the name
property in Connection
/ DataSource
is deprecated, so to work conveniently with multiple DataSource
the function addTransactionalDataSource
allows you to specify custom the name:
addTransactionalDataSource({
name: 'second-data-source',
dataSource: new DataSource(...)
});
If you don't specify a name, it defaults to default
.
Now, you can use this name
in API by passing the connectionName
property as options to explicitly define which Data Source
you want to use:
@Transactional({ connectionName: 'second-data-source' })
async fn() { ... }
OR
runInTransaction(() => {
}, { connectionName: 'second-data-source' })
Transaction Propagation
The following propagation options can be specified:
MANDATORY
- Support a current transaction, throw an exception if none exists.NESTED
- Execute within a nested transaction if a current transaction exists, behave like REQUIRED
else.NEVER
- Execute non-transactionally, throw an exception if a transaction exists.NOT_SUPPORTED
- Execute non-transactionally, suspend the current transaction if one exists.REQUIRED
(default behaviour) - Support a current transaction, create a new one if none exists.REQUIRES_NEW
- Create a new transaction, and suspend the current transaction if one exists.SUPPORTS
- Support a current transaction, execute non-transactionally if none exists.
Isolation Levels
The following isolation level options can be specified:
READ_UNCOMMITTED
- A constant indicating that dirty reads, non-repeatable reads and phantom reads can occur.READ_COMMITTED
- A constant indicating that dirty reads are prevented; non-repeatable reads and phantom reads can occur.REPEATABLE_READ
- A constant indicating that dirty reads and non-repeatable reads are prevented; phantom reads can occur.SERIALIZABLE
= A constant indicating that dirty reads, non-repeatable reads and phantom reads are prevented.
NOTE: If a transaction already exist and a method is decorated with @Transactional
and propagation
does not equal to REQUIRES_NEW
, then the declared isolationLevel
value will not be taken into account.
Hooks
Because you hand over control of the transaction creation to this library, there is no way for you to know whether or not the current transaction was successfully persisted to the database.
To circumvent that, we expose three helper methods that allow you to hook into the transaction lifecycle and take appropriate action after a commit/rollback.
runOnTransactionCommit(cb)
takes a callback to be executed after the current transaction was successfully committedrunOnTransactionRollback(cb)
takes a callback to be executed after the current transaction rolls back. The callback gets the error that initiated the rollback as a parameter.runOnTransactionComplete(cb)
takes a callback to be executed at the completion of the current transactional context. If there was an error, it gets passed as an argument.
export class PostService {
constructor(readonly repository: PostRepository, readonly events: EventService) {}
@Transactional()
async createPost(id, message): Promise<Post> {
const post = this.repository.create({ id, message });
const result = await this.repository.save(post);
runOnTransactionCommit(() => this.events.emit('post created'));
return result;
}
}
Unit Test Mocking
@Transactional
can be mocked to prevent running any of the transactional code in unit tests.
This can be accomplished in Jest with:
jest.mock('typeorm-transactional', () => ({
Transactional: () => () => ({}),
}));
Repositories, services, etc. can be mocked as usual.
API
Library Options
{
storageDriver?: StorageDriver,
maxHookHandlers?: number
}
storageDriver
- Determines which underlying mechanism (like Async Local Storage or cls-hooked) the library should use for handling and propagating transactions. By default, it's StorageDriver.CLS_HOOKED
.maxHookHandlers
- Controls how many hooks (commit
, rollback
, complete
) can be used simultaneously. If you exceed the number of hooks of same type, you get a warning. This is a useful to find possible memory leaks. You can set this options to 0
or Infinity
to indicate an unlimited number of listeners. By default, it's 10
.
Transaction Options
{
connectionName?: string;
isolationLevel?: IsolationLevel;
propagation?: Propagation;
}
Storage Driver
Option that determines which underlying mechanism the library should use for handling and propagating transactions.
The possible variants:
AUTO
- Automatically selects the appropriate storage mechanism based on the Node.js version, using AsyncLocalStorage
for Node.js versions 16 and above, and defaulting to cls-hooked
for earlier versions.CLS_HOOKED
- Utilizes the cls-hooked
package to provide context storage, supporting both legacy Node.js versions with AsyncWrap for versions below 8.2.1, and using async_hooks
for later versions.ASYNC_LOCAL_STORAGE
- Uses the built-in AsyncLocalStorage
feature, available from Node.js version 16 onwards,
⚠️ WARNING: Currently, we use CLS_HOOKED
by default for backward compatibility. However, in the next major release, this default will be switched to AUTO
.
import { StorageDriver } from 'typeorm-transactional'
initializeTransactionalContext({ storageDriver: StorageDriver.AUTO });
initializeTransactionalContext(options): void
Initialize transactional context.
initializeTransactionalContext(options?: TypeormTransactionalOptions);
Optionally, you can set some options.
addTransactionalDataSource(input): DataSource
Add TypeORM DataSource
to transactional context.
addTransactionalDataSource(new DataSource(...));
addTransactionalDataSource({ name: 'default', dataSource: new DataSource(...), patch: true });
runInTransaction(fn: Callback, options?: Options): Promise<...>
Run code in transactional context.
...
runInTransaction(() => {
...
const user = this.usersRepo.update({ id: 1000 }, { state: action });
...
}, { propagation: Propagation.REQUIRES_NEW });
...
wrapInTransaction(fn: Callback, options?: Options): WrappedFunction
Wrap function in transactional context
...
const updateUser = wrapInTransaction(() => {
...
const user = this.usersRepo.update({ id: 1000 }, { state: action });
...
}, { propagation: Propagation.NEVER });
...
await updateUser();
...
runOnTransactionCommit(cb: Callback): void
Takes a callback to be executed after the current transaction was successfully committed
@Transactional()
async createPost(id, message): Promise<Post> {
const post = this.repository.create({ id, message });
const result = await this.repository.save(post);
runOnTransactionCommit(() => this.events.emit('post created'));
return result;
}
runOnTransactionRollback(cb: Callback): void
Takes a callback to be executed after the current transaction rolls back. The callback gets the error that initiated the rollback as a parameter.
@Transactional()
async createPost(id, message): Promise<Post> {
const post = this.repository.create({ id, message });
const result = await this.repository.save(post);
runOnTransactionRollback((e) => this.events.emit(e));
return result;
}
runOnTransactionComplete(cb: Callback): void
Takes a callback to be executed at the completion of the current transactional context. If there was an error, it gets passed as an argument.
@Transactional()
async createPost(id, message): Promise<Post> {
const post = this.repository.create({ id, message });
const result = await this.repository.save(post);
runOnTransactionComplete((e) => this.events.emit(e ? e : 'post created'));
return result;
}