Rails migrations in non-Rails (and non Ruby) projects.
WHAT'S NEW
In the 1.0.x release we have moved to using Rails 3 migrations instead of maintaining our own migration related code. Just about anything you can do with Rails 3 migrations you can now do with Standalone Migrations too! This removed 95% of the code we have to maintain. Big thanks to Michael Grosser for undertaking this major rewrite!
CONTRIBUTE
Standalone Migrations relies on the contributions of the open-source community! To submit a fix or an enhancement fork the repository, checkout the develop branch, make your changes, add your name to the Contributors section in README.markdown, and send us a pull request! If you're active and do good work we'll add you as a collaborator!
USAGE
Install Ruby, RubyGems and a ruby-database driver (e.g. gem install mysql
) then:
sudo gem install standalone_migrations
Add to Rakefile
in your projects base directory:
begin
require 'tasks/standalone_migrations'
rescue LoadError => e
puts "gem install standalone_migrations to get db:migrate:* tasks! (Error: #{e})"
end
Add database configuration to db/config.yml
in your projects base directory e.g.:
development:
adapter: sqlite3
database: db/development.sqlite3
pool: 5
timeout: 5000
production:
adapter: mysql
encoding: utf8
reconnect: false
database: somedatabase_dev
pool: 5
username: root
password:
socket: /var/run/mysqld/mysqld.sock
test: &test
adapter: sqlite3
database: db/test.sqlite3
pool: 5
timeout: 5000
To create a new database migration:
rake db:new_migration name=foo_bar_migration
edit db/migrate/20081220234130_foo_bar_migration.rb
If you really want to, you can just execute raw SQL:
def self.up
execute "insert into foo values (123,'something');"
end
def self.down
execute "delete from foo where field='something';"
end
To apply your newest migration:
rake db:migrate
To migrate to a specific version (for example to rollback)
rake db:migrate VERSION=20081220234130
To migrate a specific database (for example your "testing" database)
rake db:migrate DB=test ... or ...
rake db:migrate RAILS_ENV=test
To execute a specific up/down of one single migration
rake db:migrate:up VERSION=20081220234130
To revert your last migration
rake db:rollback
To revert your last 3 migrations
rake db:rollback STEP=3
Custom configuration
By default, Standalone Migrations will assume there exists a "db/" directory in your project. But if for some reason you need a specific directory structure to work with, you can use a configuration file named .standalone_migrations in the root of your project containing the following:
db:
seeds: db/seeds.rb
migrate: db/migrate
schema: db/schema.rb
config:
database: db/config.yml
These are the configurable options available. You can omit any of the keys and Standalone Migrations will assume the default values.
Changing environment config in runtime
If you are using Heroku or have to create or change your connection
configuration based on runtime aspects (maybe environment variables),
you can use the StandaloneMigrations::Configurator.environments_config
method. Check the usage example:
require 'tasks/standalone_migrations'
StandaloneMigrations::Configurator.environments_config do |env|
env.on "production" do
if (ENV['DATABASE_URL'])
db = URI.parse(ENV['DATABASE_URL'])
return {
:adapter => db.scheme == 'postgres' ? 'postgresql' : db.scheme,
:host => db.host,
:username => db.user,
:password => db.password,
:database => db.path[1..-1],
:encoding => 'utf8'
}
end
nil
end
end
You have to put this anywhere on your Rakefile
. If you want to
change some configuration, call the #on method on the object
received as argument in your block passed to ::environments_config
method call. The #on method receives the key to the configuration
that you want to change within the block. The block should return
your new configuration hash or nil if you want the configuration
to stay the same.
Your logic to decide the new configuration need to access some data in your current configuration? Then you should receive the configuration in your block, like this:
require 'tasks/standalone_migrations'
StandaloneMigrations::Configurator.environments_config do |env|
env.on "my_custom_config" do |current_custom_config|
p current_custom_config
# => the values on your current "my_custom_config" environment
nil
end
end
Exporting Generated SQL
If instead of the database-agnostic schema.rb
file you'd like to
save the database-specific SQL generated by the migrations, simply
add this to your Rakefile
.
require 'tasks/standalone_migrations'
ActiveRecord::Base.schema_format = :sql
You should see a db/structure.sql
file the next time you run a
migration.
Contributors
- Todd Huss
- Two Bit Labs
- Class Monkeys
- Michael Grosser
- Eric Lindvall
- Steve Hodgkiss
- Rich Meyers
- Wes Bailey
- Robert J. Berger
- Federico Builes
- Ricardo Valeriano
- Gazler
- Yuu Yamashita
This work is originally based on Lincoln Stoll's blog post and David Welton's post.