Dibber
A set of tools to tidy up rails seeds.rb files.
Dibber has two compoments:
Seeder
Seeder is designed to simplify the process of pulling attributes from YAML files, and populating ActiveRecord objects with those attributes.
ProcessLog
ProcessLog provides Seeder with a simple before and after reporting tool.
Installation
Add this to your Gemfile:
gem 'dibber'
Rails Examples
You have a rails app with a ‘Thing` model, and you want to seed it with some things. `Thing` instances have the attributes `name`, `colour`, `size`. You have a YAML file `db/seeds/things.yml` that looks like this:
foo:
colour: red
size: large
bar:
colour: blue
size: small
Add this to your ‘db/seeds.rb’
Seeder = Dibber::Seeder
Seeder.seed Thing
puts Seeder.report
Then run ‘rake db:seed`
Seeder will create two new things.
You’ll then be able to do this:
thing = Thing.find_by(name: 'foo')
thing.colour ---> 'red'
Pass the name of the class to seed
All of these are equivalent commands
Dibber::Seeder.seed Thing
Dibber::Seeder.seed :thing
Dibber::Seeder.seed 'Thing'
Dynamic content
Seed content can also have dynamic content added via ERB. For example, if you want the colour of the ‘foo` thing to be either ’red’ or ‘yellow’, change ‘db/seeds/things.yml` to
foo:
colour: <%= ['red', 'yellow'].sample %>
size: large
Then when we run ‘Dibber::Seeder.seed :thing` a new `Thing` will be created with the colour set to either ’red’ or ‘yellow’.
Report
Seeder.report outputs a report detailing start and end time, and a log of how the number of things has changed
Overwriting existing entries
Seeder#build will not overwrite existing data unless directed to do so.
thing.update_attribute(:colour, 'black')
Seeder.seed :thing
thing.reload.colour ----> 'black'
Seeder.seed(:thing, overwrite: true)
thing.reload.colour ----> 'red'
Using alternative class and field name mappings
Seeder.seed calls Seeder#build to build the objects defined in the seed files. You can call the build method directly if your seed file names do not match the class name:
Seeder.new(Thing, 'other_things.yml').build
Outside Rails
Dibber can be used outside of Rails, but in this case you will need to specify the location of the seed files.
Seeder.seeds_path = "some/path/to/seeds"
You can also use this technique in Rails if you want to put your seed files in a folder other than ‘db/seeds’
More examples
Take a look at test/examples/seeds.rb for some more usage examples.
If you clone this app, you can run this example at the project root:
ruby test/examples/seeds.rb
There is also an example of process log usage:
ruby test/examples/process_logs.rb