ExTenant (ExTenant v0.2.1) View Source

Call the use ExTenant macro to inject all the required behaviour into your Application Repo module to enable all multi-tenancy functions.

Setup

In the application Config file the repo and tenanted_field settings need to be configured. ExTenant will default the tenanted_field setting to be tenant_id.

Config

config :ex_tenant,
  tenant_repo: MyAppRepo,
  tenanted_field: "tenant_id",
  get_tenant_from_subdomain_func: &your_application_get_tenant_from_subdomain_function/1
  • If the repo is not configured ExTenant will raise an exception.
  • the get_tenant_from_subdomain_func is optional if you decide to use the Plug - see example below

Repo

In your application Repo file call the use macro as per this example

def YourApplication.Repo do
  use ExTenant,
    config: [
      otp_app: :name_of_your_elixir_phoenix_app_as_atom,
      adapter: Ecto.Adapters.Postgres,
      tenanted_field: "tenant_id"
    ]
end

In order to get the tenant_id into the progress dictionary in Phoenix we recommend to use a plug - there you should retrieve the tenant name from something like the sub domain in the url. Then using the tenant name retrieve the tenant, and call:

  • Repo.put_tenant_id(tenant_id)

To insert the tenant_id into the process dictionary.

Plug

  • An example of how a Plug can be used to insert the tenant_id into the process dictionary

  • Take a look at the module ExTenant.SubdomainPlug

From here all your Repo callbacks (Repo.get/Repo.one/Repo.all etc) will have a where clause applied to them with the tenant_id injected into the clause.

In order to set the tenant_id on insert and update functions the tenant_id needs to be inserted into the attributes to be inserted. The tenanted_schema macro & the tenanted() function inserts the correct belongs_to tenanted foreign key based relationship.

Further the cast_tenant method overloads the standard Ecto.Changeset.cast function by injecting the tenant_id into the params and allowed keys. This function raises exceptions when the Repo was not configured correctly in config.exs and also if the tenant_id value is not set in the process_dictionary.

Ecto Schema/Changeset

defmodule Post do
  use ExTenant.Schema
  use ExTenant.Changeset

  tenanted_schema "posts" do
    field(:name, :string)
    field(:body, :string)

    tenanted()
  end

  defp changeset(attrs) do
    %__MODULE__{}
    |> cast_tenanted(params, [:name, :body])
  end
end

NB: If the tenant_id is not set in the changeset, Repo.insert/update callbacks will raise a Postgrex.Error (not_null_violation)

Migrations

  • documentation to be added.