annotate vendor/plugins/engines/generators/plugin_migration/USAGE @ 929:5f33065ddc4b redmine-1.3

Update to Redmine SVN rev 9414 on 1.3-stable branch
author Chris Cannam
date Wed, 27 Jun 2012 14:54:18 +0100
parents 513646585e45
children
rev   line source
Chris@0 1 Description:
Chris@0 2 The plugin migration generator assists in working with schema additions
Chris@0 3 required by plugins. Instead of running migrations from plugins directly,
Chris@0 4 the generator creates a regular Rails migration which will be responsible
Chris@0 5 for migrating the plugins from their current version to the latest version
Chris@0 6 installed.
Chris@0 7
Chris@0 8 This is important because the set of application migrations remains an
Chris@0 9 accurate record of the state of the database, even as plugins are installed
Chris@0 10 and removed during the development process.
Chris@0 11
Chris@0 12 Example:
Chris@0 13 ./script/generate plugin_migration [<plugin_name> <another_plugin_name> ...]
Chris@0 14
Chris@0 15 This will generate:
Chris@0 16
Chris@0 17 RAILS_ROOT
Chris@0 18 |- db
Chris@0 19 |-migrate
Chris@0 20 |- xxx_plugin_migrations.rb
Chris@0 21
Chris@0 22 which contains the migrations for the given plugin(s).
Chris@0 23
Chris@0 24
Chris@0 25 Advanced Usage:
Chris@0 26
Chris@0 27 There may be situations where you need *complete* control over the migrations
Chris@0 28 of plugins in your application, migrating a certainly plugin down to X, and
Chris@0 29 another plugin up to Y, where neither X or Y are the latest migrations for those
Chris@0 30 plugins.
Chris@0 31
Chris@0 32 For those unfortunate few, I have two pieces of advice:
Chris@0 33
Chris@0 34 1. Why? This is a code smell [http://c2.com/xp/CodeSmell.html].
Chris@0 35
Chris@0 36 2. Well, OK. Don't panic. You can completely control plugin migrations by
Chris@0 37 creating your own migrations. To manually migrate a plugin to a specific
Chris@0 38 version, simply use
Chris@0 39
Chris@0 40 Engines.plugins[:your_plugin_name].migrate(version)
Chris@0 41
Chris@0 42 where version is the integer of the migration this plugin should end
Chris@0 43 up at.
Chris@0 44
Chris@0 45 With great power comes great responsibility. Use this wisely.