Transcript
Multi-tenancy in Rails with PostgreSQL
Schemas
Tomasz Giereś
● Tomasz Giereś● tomaszgieres (github/twitter)● tomasz.gieres@gmail.com● almost 2 years at Lunar Logic● mainly developing Ruby on Rails
applications● also AngularJS, Backbone, Chef, bash,
anything needed● 10+ projects● work with clients
Me
● 50 lines of source code,● 1 meme,● 45 slides,● 30-40 minutes,● ask questions during the presentation,● feedback welcome
This talk and presentation
Meme
schema != schema.rb
The problem
1. You have a blog.2. Your friend wants a blog too.
Multiple instances
Multiple instances
1. Rent an another server / create new heroku application / whatever,
2. Buy a domain,3. Configure everything,4. Deploy a copy of the blog engine there.
Multiple instances
● Very easy at the beginning,● fixed price per instance* (server / hardware /
database / licences / external services ),● $100 to host a blog with 50 000 UU for you,● $100 to host a blog with 5 UU for your friend,● $100 dollars for every new instance,● deploy, administrate, backup separately,● separate admin panels etc., no easy way to
i.e. collect data from several applications
* Instance = application process(es) + database + (...)
Multiple instances
Multitenancy
Multitenancy
● One application instance serves all the blogs,
● One database for all the blogs,● No need to pay for the external services
separately?,● Easier to scale:
○ count traffic for all the blogs,○ just add more heroku dynos or application processes
when needed
Multitenancy
Multitenancy
1. Add root element to data structures:● User has a blog_id● Post has a blog_id● etc.
2. At storage and configuration level● keep the data for every tenant in a separate
storage ● dynamically switch the storage before
accessing the data
PostgreSQL schemas
● a namespace● a group of tables● an extra layer between a database and a
table● just an extra dot :)
○ <table_name>.<column_name>○ <schema_name>.<table_name>.<column_name>
PostgreSQL schemas
PostgreSQL schemas
● every tenant uses its own schema,● tables with common data are not in schemas
( in fact they are in ‘public’ schema )
PostgreSQL schemas
PostgreSQL schemas
PostgreSQL schemasanother_database=# CREATE DATABASE blogs OWNER postgres;CREATE DATABASE
blogs=# CREATE TABLE administrators (name varchar(40));CREATE TABLE
blogs=# INSERT INTO administrators (name) VALUES ('John');INSERT 0 1
PostgreSQL schemas
PostgreSQL schemasblogs=# CREATE SCHEMA rails_tips;CREATE SCHEMA
blogs=# CREATE TABLE rails_tips.posts ( title varchar(40),content text );CREATE TABLE
blogs=# INSERT INTO rails_tips.posts (title, content) VALUES ('Active Record basics', 'blah blah');INSERT 0 1
PostgreSQL schemas
PostgreSQL schemasblogs=# CREATE SCHEMA angularjs_tips;CREATE SCHEMA
blogs=# CREATE TABLE angularjs_tips.posts ( title varchar(40), content text );CREATE TABLE
blogs=# INSERT INTO angularjs_tips.posts (title, content) VALUES ('Active Record basics', 'blah blah');INSERT 0 1
PostgreSQL schemasblogs=# SELECT * FROM administrators;
name------ John(1 row)
PostgreSQL schemas
blogs=# SELECT * FROM angularjs_tips.posts;
title | content---------------+----------- Scopes basics | blah blah(1 row)
PostgreSQL schemas
Repeating schema name all the time is annyoing.
PostgreSQL schemas
united_states=# SELECT * FROM posts;
ERROR: relation "posts" does not existLINE 1: SELECT * FROM posts; ^
PostgreSQL schemas
blogs=# SHOW search_path;
search_path---------------- "$user",public(1 row)
PostgreSQL schemas
blogs=# SET search_path TO rails_tips, public;SET
blogs=# SELECT * FROM posts;
title | content----------------------+----------- Active Record basics | blah blah(1 row)
PostgreSQL schemas
Practice
Practice
● usually used with subdomains,● a client organization / a workspace / any
isolated unit = tenant ?● simpler application design and architecture,● less chance for the data leak
Practice
Rails
Wrocław
Rails
Active Record + pg gem:● supports schemas (create, drop, list),● can manipulate search path,● people prefer to execute SQL statements
anyway,● supports the same operations on the tables
within schema as on the public ones
RailsFrom Railscast:
#389 Multitenancy with PostgreSQL
with some modifications
Rails
Rails
RailsIt’s common to set search path
and current tenantin rack middleware
RailsMigrations
Rails
Useful information
● influitive / apartment (gem)● pow server● classes and methods to work in console● don’t forget about security● subdomains and schemas in testing
environment (lots of helpers needed),● rescue, sidekiq
Resources● http://www.postgresql.org/docs/9.3/static/ddl-schemas.html● http://timnew.github.io/blog/2012/07/17/use-postgres-multiple-schema-
database-in-rails/● http://blog.jerodsanto.net/2011/07/building-multi-tenant-rails-apps-with-
postgresql-schemas/● http://railscasts.com/episodes/123-subdomains-revised● http://railscasts.com/episodes/388-multitenancy-with-scopes● http://railscasts.com/episodes/389-multitenancy-with-postgresql
top related