Rubocop::SafeMigrations

Rubocop cops to help ensure that migrations are safer to run in production environments without causing downtime and database issues.

Installation

Add this line to your application's Gemfile:

gem "rubocop-safe_migrations", require: false

And then execute:

$ bundle install

Or install it yourself as:

$ gem install rubocop-safe_migrations

Usage

After installed, you have to tell rubocop to require these new cops. For doing this, add this config to your .rubocop.yml file:

require:
  - rubocop-safe_migrations

Be sure that you are not excluding migrate files for all cops either.

The cops that will be checked are:

• Migration/UpdatingDataInMigration
• Migration/RenamingTableInMigration

Updating data in migration

This cop will check if active record migrations have any method that runs updates, creations or deletions on your database.

This is important to be avoided if you have your deploy pipeline configured to run database migrations on deploy or build time. Having data being manipulated or updated on deploy can cause unexpected downtime to your application database.

By default, all active record methods that generate update, create or delete queries are checked by the cop, and if used on migrations an offense will be generated.

To turn some method available to be used on migration, just add it to AllowedMethods config on rubocop.yml, for example:

Migration/UpdatingDataInMigration:
  AllowedMethods:
    - toggle

Using the configuration above, the cop will not add an offense when the toggle method is used on migrations.

Renaming table in migration

This cop will check if you have migrations that are renaming tables already created on your database.

This should be avoided because your tables can have triggers configured, that will stop working after the table gets renamed. Besides that, it can lead to an inconsistent scenario where you will keep indexes and foreign_keys with the old table name, and if a DBA or a developer see those in database, it can be confusing and create misunderstandings.

This cop has no options, the only thing that can be done is disabled it on rubocop.yml:

Migration/RenamingTableInMigration:
  Enabled: false

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/jplethier/rubocop-safe_migrations. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Rubocop::SafeMigrations project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.

TODO

For Updating data in migration cop

• Adds check to active record update_counters method called on migration
• Adds check to active record create method called on migration
• Adds check to active record create_or_update method called on migration
• Adds check to active record decrement method called on migration
• Adds check to active record increment method called on migration
• Adds check to active record find_or_create method called on migration
• Adds check to string sql execution with updates, inserts or deletions
• Position offense message on the method being called, not in the end of line
• Adds option to be able to add custom methods to blacklist

For renaming table in migration cop

• Adds a check to string sql execution renaming table
• [Maybe] Adds a possibility to renaming table if all indexes and foreign keys are renamed as well

For new rules

• Creates a rule to check if a column is being added with a default value
• Creates a rule to create indexes safier