seed_helper

SeedHelper

SeedHelper is a small gem I created while I was working on various projects with terrible Seed files.

Purpose

The goal of SeedHelper is to provide some commonly required functionality to make creating Seed files easier.

Dependencies

SeedHelper uses the colorize gem to present output.

Example: Seed implementation

I use rake tasks to create my seed data. That way you can easily run individual tasks for seeding specific pieces of data.

Using SeedHelper, a seed task might look like:

# in lib/tasks/seeds/create_roles.rake

SeedHelper.create_seed_task(:create_roles) do

  ["Admin", "Regular"].each do |role_name|

    # Will print out a red message if Role fails to save
    # Will print out a green message is Role succesfully creates
    # Will print out a cyan message if Role already exists
    SeedHelper.find_or_create_resource(Role, {name: role_name})

  end

end

# in lib/tasks/seeds/create_users.rake

include SeedHelper

# Specify a dependency on roles, so that running this task will first
# run the create_roles task
SeedHelper.create_seed_task(:create_users, [:create_roles]) do

  [
    ["[e-mail]", Role.admin],
    ["[e-mail]", Role.other]
  ].each do |email, role_name|

    role = Role.find_by(name: role_name)
    admin = SeedHelper.find_or_create_resource(User, {email: email, role: role_name})

  end

end

By default, the .find_or_create_resource method uses the hash you provide it to find a User with those attributes. It can then determine whether or not it needs to create a new User.

This becomes problematic when we have a lot of fields, since we don't want to try and identify a User by some of those fields - password, for example.

In that case, we can pass through a third argument of all those additional fields:

SeedHelper.find_or_create_resource(User, {email: email}, {password: "password", role: role_name})

Example: Using FactoryGirl for a single object

Sometimes you'll want to create an object using FactoryGirl. You can pass a block to .find_or_create_resource to achieve this. EG:

SeedHelper.find_or_create_resource(User, {email: "[e-mail]"}, {password: "Alligator8"}) do |attributes|
  FactoryGirl.build(:user, :admin, :with_profile_picture, attributes)
end

This will return a User that matches {email: "[e-mail]"} (and print out a message saying the object already exists), or it will use the FG call to create a new object (and return a success message if the object returned is valid).

NB: You should return an unpersisted object in this block.

Example: Using FactoryGirl for a collection of objects

If you don't want to provide specific attributes, you can use the .bulk_create function to do so. EG:

# If MyClass.count > 0, an already created message will be shown
# If MyClass.count == 0, the block will be run
# If the block fails, you'll get a red error message with the exception printed out.
SeedHelper.bulk_create(MyClass) do
  FactoryGirl.create_list(:my_class, 5)
end

If you want to bulk create some associated objects for a given object, you can pass a hash of attributes to scope the .bulk_create by:

Client.all.each do |client|
  SeedHelper.bulk_create(User, {client_id: client.id}) do |client_attributes|
    FactoryGirl.create_list(:user, 5, client_attributes)
  end
end

You can pass a custom message through:

Client.all.each do |client|
  SeedHelper.bulk_create(User, {client_id: client.id}, "Users for #{client.name}") do |client_attributes|
    FactoryGirl.create_list(:user, 5, client_attributes)
  end
end

# Users for DeathCorp already exists
# Created Users for DeathCorp
# Failed to create Users for DeathCorp

Example: Output

SeedHelper provides multiple methods for showing output that can be used outside of the create_resource method:

• message A general purpose message, generally used as a header. White by default.
• success Indicates a seed function was successful. Green by default.
• error Indicates a seed function has failed. Red by default.
• resource_already_exists Indicates that the data already exists in the database.
• special_message Show a purple multiline message. I use this to show logins for seed users.

Example: Creating a rake task

SeedHelper gives you an easy way to create consistently named rake tasks. Usage is as follows:

# rake db:seed:task_name
# :environment is automatically added as a dependency
SeedHelper.create_seed_task(:task_name)

# rake db:seed:second_task_name
# Dependent on :task_name, rake db:seed:task_name will be run before :second_task_name
SeedHelper.create_seed_task(:second_task_name, [:task_name])

# rake db:seed:third_task_name
# No dependencies (other than environment) but with a custom title. This will show up as
# description of task in `rake -T` and will be printed to screen when task runs
SeedHelper.create_seed_task(:third_task_name, [], "My sick name")