Achieving Multi-tenancy using Micronaut-data with MongoDB

[Saumya999]

I want to achieve multi tenancy using MongoDB , I am using Micronaut Kotlin with Micronaut-data for database connectivity.
I am not using HttpTenantResolver provided by Micronaut. I wrote my own logic in filter chain.

Now I have the tenant-id depend ending on that with some logic I want to override the mongoDb connection String mentioned in my application.yml . can anyone please help me how I can do that ?

and I avoided in built HttpTenantResolver because I don't know how many tenants will be there. It will dynamically increase - for each tenant database will be different with common collection schema ( with different data in it ). That's why it's impossible to maintain all the datasource connection string in Yml. It should be built dynamically in runtime.

thanks in advance

[graemerocher]

does this not help? https://micronaut-projects.github.io/micronaut-data/latest/guide/#multitenancy

[Saumya999]

If you see in the Doc - they are maintaining 2 server urls in the application.yml for FOO and Bar.
Here my requirement is little different. But in my case beforehand I don't know how many tenants will be there.

For example:
one endpoint = /register that will be public which doesn't need any tenantId in Header . It will create and registration id for the customer. Basically That generated Id will be tenant-id for respective calls. and tenant-Id will be the databse Name. Database will contain - per customer products, orders, billings etc as collections. (B2B)

application.yml

mongodb:
  uri: 'mongodb://localhost:27017/{tenantId}

This is something I need. - For now I am mentioning one fixed value in place of tenantId variable.

this tenantId I am getting below

@Singleton
@Filter("/**")
class TenantFilter(private val connectionStorage: ConnectionStorage) : HttpServerFilter{

  // TODO Multi-Tenancy implementation to add x-tenant-id in Header for dynamic database

  override fun doFilter(request: HttpRequest<*>?, chain: ServerFilterChain?): Publisher<MutableHttpResponse<*>> {
      val attribute: @Nullable String = request?.headers?.get("x-tenant-id") ?: throw RuntimeException("Missing Tenant Header")
      if (chain != null) {
          connectionStorage.setConnection(attribute)
          return chain.proceed(request)
      } else {
          throw RuntimeException("proper request chaining not happening")
      }
  }


}

@Singleton
class ConnectionStorage {
    private var threadLocal:ThreadLocal<String> = ThreadLocal()
    fun setConnection(tenantId: String) {
        threadLocal.set(tenantId)
    }
    fun removeConnection(tenantId: String) {
        threadLocal.remove()
    }
    fun getConnection(): String {
        return threadLocal.get()
    }
}

Now tenantId is set in ThreadLocal storage. I need to dynamically override the connection String of MongoDB in runtime.

@graemerocher Please check if you could help and save me :)

[dstepanov]

Please don't use thread-local but our new propagation API. (see Core docs)
The only way right now would be to replace the current MongoClient definition with some proxy that will delegate to the tenant client.

[Saumya999]

Can you give me some code examples how to achieve this ? I didn't get