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unleash.unleash/src/lib/db/transaction.ts
Gastón Fournier db04a1eaa8
chore: introduce type to prevent potential issues (#5066)
## About the changes
This small improvement aims to help developers when instantiating
services. They need to be constructed without injecting services or
stores created elsewhere so they can be bound to the same transactional
scope.

This suggests that you need to create the services and stores on your
own
2023-10-17 12:30:44 +02:00

94 lines
3.4 KiB
TypeScript

import { Knex } from 'knex';
import { IUnleashConfig } from 'lib/server-impl';
export type KnexTransaction = Knex.Transaction;
export type MockTransaction = null;
export type UnleashTransaction = KnexTransaction | MockTransaction;
export type TransactionCreator<S> = <T>(
scope: (trx: S) => void | Promise<T>,
) => Promise<T>;
export const createKnexTransactionStarter = (
knex: Knex,
): TransactionCreator<UnleashTransaction> => {
function transaction<T>(
scope: (trx: KnexTransaction) => void | Promise<T>,
) {
if (!knex) {
console.warn(
'It looks like your DB is not provided. Very often it is a test setup problem in setupAppWithCustomConfig',
);
}
return knex.transaction(scope);
}
return transaction;
};
export type DeferredServiceFactory<S> = (db: Knex) => S;
/**
* Services need to be instantiated with a knex instance on a per-transaction basis.
* Limiting the input parameters, makes sure we don't inject already instantiated services
* that might be bound to a different transaction.
*/
export type ServiceFactory<S> = (
config: IUnleashConfig,
) => DeferredServiceFactory<S>;
export type WithTransactional<S> = S & {
transactional: <R>(fn: (service: S) => R) => Promise<R>;
};
/**
* @deprecated this is a temporary solution to deal with transactions at the store level.
* Ideally, we should handle transactions at the service level (each service method should be transactional).
* The controller should define the transactional scope as follows:
* https://github.com/Unleash/unleash/blob/cb034976b93abc799df774858d716a49f645d669/src/lib/features/export-import-toggles/export-import-controller.ts#L206-L208
*
* To be able to use .transactional method, services should be instantiated like this:
* https://github.com/Unleash/unleash/blob/cb034976b93abc799df774858d716a49f645d669/src/lib/services/index.ts#L282-L284
*
* This function makes sure that `fn` is executed in a transaction.
* If the db is already in a transaction, it will execute `fn` in that transactional scope.
*
* https://github.com/knex/knex/blob/bbbe4d4637b3838e4a297a457460cd2c76a700d5/lib/knex-builder/make-knex.js#L143C5-L144C88
*/
export async function inTransaction<R>(
db: Knex,
fn: (db: Knex) => R,
): Promise<R> {
if (db.isTransaction) {
return fn(db);
}
return db.transaction(async (tx) => fn(tx));
}
export function withTransactional<S>(
serviceFactory: (db: Knex) => S,
db: Knex,
): WithTransactional<S> {
const service = serviceFactory(db) as WithTransactional<S>;
service.transactional = async <R>(fn: (service: S) => R) =>
// Maybe: inTransaction(db, async (trx: Knex.Transaction) => fn(serviceFactory(trx)));
// this assumes that the caller didn't start a transaction already and opens a new one.
db.transaction(async (trx: Knex.Transaction) => {
const transactionalService = serviceFactory(trx);
return fn(transactionalService);
});
return service;
}
/** Just for testing purposes */
export function withFakeTransactional<S>(service: S): WithTransactional<S> {
const serviceWithFakeTransactional = service as WithTransactional<S>;
serviceWithFakeTransactional.transactional = async <R>(
fn: (service: S) => R,
) => fn(serviceWithFakeTransactional);
return serviceWithFakeTransactional;
}