sdelamo/gorm-multitenancy-additional-tenant-query

Grails Multi-Tenancy Example

The cache branch of this repository contains logic showing how to use Grails Cache Plugin with the tenant Id as part of the cache key.

The sample code

• Overrides bean customCacheKeyGenerator. It adds the tenantId as part of the key.
• Creates several cache related classes based on the plugin default CustomCacheKeyGenerator
• Adds a EvictController and service. They show how to evict cache for a particular tenant.
• Adds @Cacheable to the BookListService.

When the cache is not hit you will see a log line:

INFO --- [nio-8080-exec-2] example.BookListService : not cached

The index page of the application http://localhost:8080 contains links to evict the cache.

---

This Grails application uses GORM for Hibernate.

It uses DISCRIMINATOR multi-tenancy mode by setting at grails-app/conf/application.yml the following:

grails:
    gorm:
        multiTenancy:
            mode: DISCRIMINATOR

It has a domain class Book which uses a custom field tenant as the tenancy discriminator.

package example

import grails.compiler.GrailsCompileStatic
import grails.gorm.MultiTenant

@GrailsCompileStatic
class Book implements MultiTenant<Book> {
    ...
    String tenant
    static constraints = {
...
    static mapping = {
        tenantId name:'tenant'
    }
}

In grails-app/init/BootStrap.groovy multiple Books are saved. To select the tenant, for which the books are being saved, the method MultiTenant::withTenant(Serializable, Closure) is used.

• For tenant groovy, the application saves 5 books
• For tenant grails, the application saves 8 books
• For tenant micronaut, the application saves 1 books

To save the books, Boostrap injects BookService a GORM Data Service annotaed with @CurrentTenant, an annotation which resolves the current tenant for the context of a class or method. It uses the method BookService::save(String, String, String, String, String)

The application exposes following endpoints:

• GET /books/groovy returns books of current tenant groovy
• GET /books/grails returns books of current tenant grails
• GET /books/micronaut returns books of current tenant micronaut
• GET /books/groovygrails returns books of current tenant groovy and books of an extra tenant grails

To allow queries which fetch current tenant items plus items belonging to other tenant BookService extends an abstractclass DataService

@CompileStatic
@CurrentTenant
@Service(Book)
abstract class BookService extends DataService<Book> {

    @Autowired
    HibernateDatastore hibernateDatastore

    @Override
    HibernateDatastore getHibernateDataStore() {
        return this.hibernateDatastore
    }

    @Override
    DetachedCriteria<Book> getDetachedCriteria() {
        Book.where {}
    }
    ...

To allow fetching information coming from multiple tenants DataService<T> exposes a method:

DetachedCriteria<T> criteriaInTenants(String... additionalTenant = null)

DetachedCriteria allows for dynamic constructions of queries. If you build the criteria with criteriaInTenant execute the query within the Closure of Tenants.withoutId(Closure). Example:

    ...
    Number count(String additionalTenant = null) {
        DetachedCriteria<Book> c = criteriaInTenants(additionalTenant)
        Tenants.withoutId {
            c.count()
        }
    }
    ...