About This Repository

This is a boilerplate for a BE with multitenancy on row level. Using nestjs as main framework and sequelize as orm

Folders structure

• config, migrations and seeders are used by sequelize-cli to setup the DB
• src
  • lib common providers shared accross all tenants
  • models sequelize models
  • shippings module where I want to implement the multi-tenancy

Multi tenancy implementation

To keep it simple there are only essential elements to understand the requirements:

Database models

• Tenant (list of tenants)
• TenantsConfig (every tenant should have its own configs)
• User (list of users)

multi-tananted:

• Shippings (this table has also a tenantId field for the row level tenancy)

Controllers for shipping

There should be only controller for creating shippings.

POST /shippings should read the x-tenant header and through shippingService load the proper fedexService with the tenant config.

This boilerplate is for example only, you can change it as you think is better.

Shipping module

Inside the shippings.service.ts there is a rough implementation of what i'm trying to achieve

TODO

Im looking for a BE structure that can handle multiple tenants (10-20 tenants)

1. the BE should be aware of TenantConfig changes, to always use the latest config data (without app reload)

   this can be done moving tenantConfigs store to a class (then invocking the class from the tenant.intercepto, and when updating the db, changing also the tenantConfig store)

2. ideally providers should be instantiated just once for tenant( and then cached somehow, until config changed)

   imo it is a task that requires advanced knowledge in nestjs and probably it requires a complete refactoring of the codebase. I'm exploring some solutions

   1. choose a nomenclature for providers and then call them by @Inject('fedexService'+tenantId) //fedexService1 https://docs.nestjs.com/providers#property-based-injection
   2. Load all tenant + tenant configs at bootstrap and register all services at once https://docs.nestjs.com/fundamentals/custom-providers#factory-providers-usefactory
   3. Do all at module level: idk with contextId, useFactory or dynamic instantiation of provide https://docs.nestjs.com/fundamentals/module-ref#registering-request-provider

3. there should be some centralized middleware/interceptor to manage/return tenants configs
4. there should be some centalized middleware/interceptor to check if user belongs to the declared tenant

   this can be achieved by adding a guard that has loaded all users and tenant, and checks if user belongs to declared tenant