Add multitenancy with apartment

Co-Authored-By: Javi Martín <javim@elretirao.net>

Gemfile

@@ -49,6 +49,7 @@ gem "recipient_interceptor", "~> 0.3.1"
 gem "redcarpet", "~> 3.5.1"
 gem "responders", "~> 3.0.1"
 gem "rinku", "~> 2.0.6", require: "rails_rinku"
+gem "ros-apartment", "~> 2.11.0", require: "apartment"
 gem "sassc-rails", "~> 2.1.2"
 gem "savon", "~> 2.13.0"
 gem "sitemap_generator", "~> 6.3.0"

Gemfile.lock

@@ -472,7 +472,7 @@ GEM
     pronto-scss (0.11.0)
       pronto (~> 0.11.0)
       scss_lint (~> 0.43, >= 0.43.0)
-    public_suffix (5.0.0)
+    public_suffix (4.0.7)
     puma (4.3.12)
       nio4r (~> 2.0)
     racc (1.6.0)
@@ -534,6 +534,11 @@ GEM
     retriable (3.1.2)
     rexml (3.2.5)
     rinku (2.0.6)
+    ros-apartment (2.11.0)
+      activerecord (>= 5.0.0, < 7.1)
+      parallel (< 2.0)
+      public_suffix (>= 2.0.5, < 5.0)
+      rack (>= 1.3.6, < 3.0)
     rspec-core (3.11.0)
       rspec-support (~> 3.11.0)
     rspec-expectations (3.11.0)
@@ -784,6 +789,7 @@ DEPENDENCIES
   redcarpet (~> 3.5.1)
   responders (~> 3.0.1)
   rinku (~> 2.0.6)
+  ros-apartment (~> 2.11.0)
   rspec-rails (~> 5.1.2)
   rubocop (~> 1.35.1)
   rubocop-performance (~> 1.11.4)

app/models/tenant.rb

@@ -0,0 +1,37 @@
+class Tenant < ApplicationRecord
+  validates :schema,
+    presence: true,
+    uniqueness: true,
+    exclusion: { in: ->(*) { excluded_subdomains }}
+  validates :name, presence: true, uniqueness: true
+
+  after_create :create_schema
+  after_update :rename_schema
+  after_destroy :destroy_schema
+
+  def self.excluded_subdomains
+    Apartment::Elevators::Subdomain.excluded_subdomains + %w[mail]
+  end
+
+  def self.switch(...)
+    Apartment::Tenant.switch(...)
+  end
+
+  private
+
+    def create_schema
+      Apartment::Tenant.create(schema)
+    end
+
+    def rename_schema
+      if saved_change_to_schema?
+        ActiveRecord::Base.connection.execute(
+          "ALTER SCHEMA \"#{schema_before_last_save}\" RENAME TO \"#{schema}\";"
+        )
+      end
+    end
+
+    def destroy_schema
+      Apartment::Tenant.drop(schema)
+    end
+end

config/initializers/apartment.rb

@@ -0,0 +1,117 @@
+# You can have Apartment route to the appropriate Tenant by adding some Rack middleware.
+# Apartment can support many different "Elevators" that can take care of this routing to your data.
+# Require whichever Elevator you're using below or none if you have a custom one.
+#
+# require "apartment/elevators/generic"
+# require "apartment/elevators/domain"
+require "apartment/elevators/subdomain"
+# require "apartment/elevators/first_subdomain"
+# require "apartment/elevators/host"
+
+#
+# Apartment Configuration
+#
+Apartment.configure do |config|
+  config.seed_after_create = true
+
+  # Add any models that you do not want to be multi-tenanted, but remain in the global (public) namespace.
+  # A typical example would be a Customer or Tenant model that stores each Tenant's information.
+  #
+  config.excluded_models = %w[Tenant]
+
+  # In order to migrate all of your Tenants you need to provide a list of Tenant names to Apartment.
+  # You can make this dynamic by providing a Proc object to be called on migrations.
+  # This object should yield either:
+  # - an array of strings representing each Tenant name.
+  # - a hash which keys are tenant names, and values custom db config
+  # (must contain all key/values required in database.yml)
+  #
+  # config.tenant_names = lambda{ Customer.pluck(:tenant_name) }
+  # config.tenant_names = ["tenant1", "tenant2"]
+  # config.tenant_names = {
+  #   "tenant1" => {
+  #     adapter: "postgresql",
+  #     host: "some_server",
+  #     port: 5555,
+  #     database: "postgres" # this is not the name of the tenant's db
+  #                          # but the name of the database to connect to before creating the tenant's db
+  #                          # mandatory in postgresql
+  #   },
+  #   "tenant2" => {
+  #     adapter:  "postgresql",
+  #     database: "postgres" # this is not the name of the tenant's db
+  #                          # but the name of the database to connect to before creating the tenant's db
+  #                          # mandatory in postgresql
+  #   }
+  # }
+  # config.tenant_names = lambda do
+  #   Tenant.all.each_with_object({}) do |tenant, hash|
+  #     hash[tenant.name] = tenant.db_configuration
+  #   end
+  # end
+  #
+  config.tenant_names = -> { Tenant.pluck :schema }
+
+  # PostgreSQL:
+  #   Specifies whether to use PostgreSQL schemas or create a new database per Tenant.
+  #
+  # MySQL:
+  #   Specifies whether to switch databases by using `use` statement or re-establish connection.
+  #
+  # The default behaviour is true.
+  #
+  # config.use_schemas = true
+
+  #
+  # ==> PostgreSQL only options
+
+  # Apartment can be forced to use raw SQL dumps instead of schema.rb for creating new schemas.
+  # Use this when you are using some extra features in PostgreSQL that can't be represented in
+  # schema.rb, like materialized views etc. (only applies with use_schemas set to true).
+  # (Note: this option doesn't use db/structure.sql, it creates SQL dump by executing pg_dump)
+  #
+  # config.use_sql = false
+
+  # There are cases where you might want some schemas to always be in your search_path
+  # e.g when using a PostgreSQL extension like hstore.
+  # Any schemas added here will be available along with your selected Tenant.
+  #
+  # config.persistent_schemas = %w{ hstore }
+
+  # <== PostgreSQL only options
+  #
+
+  # By default, and only when not using PostgreSQL schemas, Apartment will prepend the environment
+  # to the tenant name to ensure there is no conflict between your environments.
+  # This is mainly for the benefit of your development and test environments.
+  # Uncomment the line below if you want to disable this behaviour in production.
+  #
+  # config.prepend_environment = !Rails.env.production?
+
+  # When using PostgreSQL schemas, the database dump will be namespaced, and
+  # apartment will substitute the default namespace (usually public) with the
+  # name of the new tenant when creating a new tenant. Some items must maintain
+  # a reference to the default namespace (ie public) - for instance, a default
+  # uuid generation. Uncomment the line below to create a list of namespaced
+  # items in the schema dump that should *not* have their namespace replaced by
+  # the new tenant
+  #
+  # config.pg_excluded_names = ["uuid_generate_v4"]
+
+  # Specifies whether the database and schema (when using PostgreSQL schemas) will prepend in ActiveRecord log.
+  # Uncomment the line below if you want to enable this behavior.
+  #
+  # config.active_record_log = true
+end
+
+# Setup a custom Tenant switching middleware. The Proc should return the name of the Tenant that
+# you want to switch to.
+# Rails.application.config.middleware.use Apartment::Elevators::Generic, lambda { |request|
+#   request.host.split(".").first
+# }
+
+# Rails.application.config.middleware.use Apartment::Elevators::Domain
+Rails.application.config.middleware.use Apartment::Elevators::Subdomain
+# Rails.application.config.middleware.use Apartment::Elevators::FirstSubdomain
+# Rails.application.config.middleware.use Apartment::Elevators::Host
+Apartment::Elevators::Subdomain.excluded_subdomains = %w[public www]

db/migrate/20180502075740_create_tenants.rb

@@ -0,0 +1,12 @@
+class CreateTenants < ActiveRecord::Migration[4.2]
+  def change
+    create_table :tenants do |t|
+      t.string :name
+      t.string :schema
+      t.timestamps null: false
+
+      t.index :name, unique: true
+      t.index :schema, unique: true
+    end
+  end
+end

db/schema.rb

@@ -1555,6 +1555,15 @@ ActiveRecord::Schema.define(version: 2022_09_15_154808) do
     t.index ["proposals_count"], name: "index_tags_on_proposals_count"
   end
 
+  create_table "tenants", id: :serial, force: :cascade do |t|
+    t.string "name"
+    t.string "schema"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["name"], name: "index_tenants_on_name", unique: true
+    t.index ["schema"], name: "index_tenants_on_schema", unique: true
+  end
+
   create_table "topics", id: :serial, force: :cascade do |t|
     t.string "title", null: false
     t.text "description"

spec/factories/administration.rb

@@ -98,4 +98,9 @@ FactoryBot.define do
     value_es { "Texto en español" }
     value_en { "Text in english" }
   end
+
+  factory :tenant do
+    sequence(:name) { |n| "Tenant #{n}" }
+    sequence(:schema) { |n| "subdomain#{n}" }
+  end
 end

spec/models/tenant_spec.rb

@@ -0,0 +1,64 @@
+require "rails_helper"
+
+describe Tenant do
+  describe "validations" do
+    let(:tenant) { build(:tenant) }
+
+    it "is valid" do
+      expect(tenant).to be_valid
+    end
+
+    it "is not valid without a schema" do
+      tenant.schema = nil
+      expect(tenant).not_to be_valid
+    end
+
+    it "is not valid with an already existing schema" do
+      expect(create(:tenant, schema: "subdomainx")).to be_valid
+      expect(build(:tenant, schema: "subdomainx")).not_to be_valid
+    end
+
+    it "is not valid with an excluded subdomain" do
+      %w[mail public www].each do |subdomain|
+        tenant.schema = subdomain
+        expect(tenant).not_to be_valid
+      end
+    end
+
+    it "is not valid without a name" do
+      tenant.name = ""
+      expect(tenant).not_to be_valid
+    end
+
+    it "is not valid with an already existing name" do
+      expect(create(:tenant, name: "Name X")).to be_valid
+      expect(build(:tenant, name: "Name X")).not_to be_valid
+    end
+  end
+
+  describe "#create_schema" do
+    it "creates a schema creating a record" do
+      create(:tenant, schema: "new")
+      expect { Tenant.switch("new") { nil } }.not_to raise_exception
+    end
+  end
+
+  describe "#rename_schema" do
+    it "renames the schema when updating the schema" do
+      tenant = create(:tenant, schema: "typo")
+      tenant.update!(schema: "notypo")
+
+      expect { Tenant.switch("typo") { nil } }.to raise_exception(Apartment::TenantNotFound)
+      expect { Tenant.switch("notypo") { nil } }.not_to raise_exception
+    end
+  end
+
+  describe "#destroy_schema" do
+    it "drops the schema when destroying a record" do
+      tenant = create(:tenant, schema: "wrong")
+      tenant.destroy!
+
+      expect { Tenant.switch("wrong") { nil } }.to raise_exception(Apartment::TenantNotFound)
+    end
+  end
+end

spec/rails_helper.rb

@@ -65,3 +65,14 @@ Capybara.enable_aria_label = true
 Capybara.disable_animation = true
 
 OmniAuth.config.test_mode = true
+
+def with_subdomain(subdomain, &block)
+  app_host = Capybara.app_host
+
+  begin
+    Capybara.app_host = "http://#{subdomain}.lvh.me"
+    block.call
+  ensure
+    Capybara.app_host = app_host
+  end
+end

spec/system/multitenancy_spec.rb

@@ -0,0 +1,63 @@
+require "rails_helper"
+
+describe "Multitenancy" do
+  before do
+    create(:tenant, schema: "mars")
+    create(:tenant, schema: "venus")
+  end
+
+  scenario "Disabled features", :no_js do
+    Tenant.switch("mars") { Setting["process.debates"] = true }
+    Tenant.switch("venus") { Setting["process.debates"] = nil }
+
+    with_subdomain("mars") do
+      visit debates_path
+
+      expect(page).to have_css "#debates"
+    end
+
+    with_subdomain("venus") do
+      expect { visit debates_path }.to raise_exception(FeatureFlags::FeatureDisabled)
+    end
+  end
+
+  scenario "Sign up into subdomain" do
+    with_subdomain("mars") do
+      visit "/"
+      click_link "Register"
+
+      fill_in "Username", with: "Marty McMartian"
+      fill_in "Email", with: "marty@consul.dev"
+      fill_in "Password", with: "20151021"
+      fill_in "Confirm password", with: "20151021"
+      check "By registering you accept the terms and conditions of use"
+      click_button "Register"
+
+      confirm_email
+
+      expect(page).to have_content "Your account has been confirmed."
+    end
+  end
+
+  scenario "Users from another tenant can't sign in" do
+    Tenant.switch("mars") { create(:user, email: "marty@consul.dev", password: "20151021") }
+
+    with_subdomain("mars") do
+      visit new_user_session_path
+      fill_in "Email or username", with: "marty@consul.dev"
+      fill_in "Password", with: "20151021"
+      click_button "Enter"
+
+      expect(page).to have_content "You have been signed in successfully."
+    end
+
+    with_subdomain("venus") do
+      visit new_user_session_path
+      fill_in "Email or username", with: "marty@consul.dev"
+      fill_in "Password", with: "20151021"
+      click_button "Enter"
+
+      expect(page).to have_content "Invalid Email or username or password."
+    end
+  end
+end