angry-boss/multi

Multi-tenancy

Config:

Create initializer file. config/initializers/multi.rb

Put into file

`` require_relative '../lib/multi_tenancy/multi/logic/subdomain'

Multi.configure do |config| config.middleware.use Multi::Logic::Subdomain end ``

Then,

1. Create lib/tasks/db_enhancements.rake

Put into file

``

namespace :db do desc 'Also create shared_extensions Schema' task :extensions => :environment do # Create Schema ActiveRecord::Base.connection.execute 'CREATE SCHEMA IF NOT EXISTS shared_extensions;' # Enable Hstore ActiveRecord::Base.connection.execute 'CREATE EXTENSION IF NOT EXISTS HSTORE SCHEMA shared_extensions;' # Enable UUID-OSSP ActiveRecord::Base.connection.execute 'CREATE EXTENSION IF NOT EXISTS "uuid-ossp" SCHEMA shared_extensions;' # Enable pgcrypto ActiveRecord::Base.connection.execute 'CREATE EXTENSION IF NOT EXISTS "pgcrypto" SCHEMA shared_extensions;' # Grant usage to public ActiveRecord::Base.connection.execute 'GRANT usage ON SCHEMA shared_extensions to public;' end end

Rake::Task["db:create"].enhance do Rake::Task["db:extensions"].invoke end

Rake::Task["db:test:purge"].enhance do Rake::Task["db:extensions"].invoke end

``

2. Drop database, Create new, Run task, Make migration rake db:drop rake db:create rake db:extensions rake db:migrate
3. Add extensions into database.yml ``

# database.yml
...
adapter: postgresql
schema_search_path: "public,shared_extensions"
...

4. and now

# config/initializers/multi.rb
...
config.persistent_schemas = ['shared_extensions']
...

Usage

to create a new tenant, run the following command:

Multi::Tenant.create('tenant_name')

Switching Tenants

To switch tenants using Multi, use the following command:

Multi::Tenant.switch('tenant_name') do
  # ...
end

To return to the default tenant, call switch with no arguments.

Switching Tenants per request

Multi is Rack middleware. Multi::Logic::Subdomain switch on your record and routing to your data.

to exclude a domain, for example www like a subdomain, in an initializer set the following:

# config/initializers/multi.rb
Multi::Logic::Subdomain.excluded_subdomains = ['www']

Middleware Considerations

In the examples above, we show the Apartment middleware being appended to the Rack stack with

Rails.application.config.middleware.use Multi::Logic::Subdomain

important to consider that you may want to maintain the "selected" tenant through different parts of the Rack application stack. For example, devise, gem adds the Warden::Manager middleware at the end of the stack in the examples above, our Apartment::Elevators::Subdomain middleware would come after it. Trouble is, Multi resets the selected tenant and redirects authentication in context of the "public" tenant. To resolve this issue:

Rails.application.config.middleware.insert_before Warden::Manager, Multi::Logic::Subdomain

To drop tenants:

Multi::Tenant.drop('tenant_name')

schema is dropped and all data from itself

Excluding models

config.excluded_models = ["User", "Company"]        # these models will not be multi-tenanted, but remain in the global (public) namespace

Managing Migrations

In order to migrate all of your tenants (or postgresql schemas) you need to provide a list of dbs to Apartment. You can make this dynamic by providing a Proc object to be called on migrations. This object should yield an array of string representing each tenant name. Example:

# Dynamically get tenant names to migrate
config.tenant_names = lambda{ Customer.pluck(:tenant_name) }

# Use a static list of tenant names for migrate
config.tenant_names = ['tenant1', 'tenant2']

You can then migrate your tenants using the normal rake task:

rake db:migrate

This just invokes Multi::Tenant.migrate(#{tenant_name})

disable default migrating of all tenants with db:migrate Multi.db_migrate_tenants = false in your Rakefile. Nlmt::Application.load_tasks

Tenants on different servers

You can store your tenants in different databases on one or more servers. To do it, specify your tenant_names as a hash, keys being the actual tenant names, values being a hash with the database configuration to use.

Example:

config.with_multi_server_setup = true
config.tenant_names = {
  'tenant1' => {
    adapter: 'postgresql',
    host: 'some_server',
    port: 5555,
    database: 'postgres' # this is not the name of the tenant's db
  }
}
# or using a lambda:
config.tenant_names = lambda do
  Tenant.all.each_with_object({}) do |tenant, hash|
    hash[tenant.name] = tenant.db_configuration
  end
end

Callbacks

execute callbacks when switching between tenants or creating a new one:

• before_create
• after_create
• before_switch
• after_switch

You can register a callback using ActiveSupport::Callbacks the following way:

require 'multi/adapters/abstract_adapter'

module Multi
  module Adapters
    class AbstractAdapter
      set_callback :switch, :before do |object|
        ...
      end
    end
  end
end

Tests

• Rake tasks (in multi-tenancy) setup dbs for tests