db.rake tasks for cassanity + migrations.

db.rake

# ******************************************************************************
# NOTE: You will need to replace keyspace and migrations_path in the rake tasks 
# below with whatever makes sense for your application. You will also need a 
# task named environment that loads whatever is need to make cassanity available.
# ******************************************************************************
namespace :db do
  desc "Run any pending migrations."
  task :migrate => :environment do
    require 'cassanity/migrator'

    keyspace = Cassanity::Client.new[:my_app]
    migrations_path = Rails.root.join('db', 'migrate')

    migrator = Cassanity::Migrator.new(keyspace, migrations_path)

    if ENV["VERSION"]
      version = ENV["VERSION"].to_i
      direction = ENV.fetch('DIRECTION', :up).to_sym
      migrator.migrate_to(version, direction)
    else
      migrator.migrate
    end
  end

  desc "List pending migrations."
  task :pending => :environment do
    require 'cassanity/migrator'

    keyspace = Cassanity::Client.new[:my_app]
    migrations_path = Rails.root.join('db', 'migrate')

    migrator = Cassanity::Migrator.new(keyspace, migrations_path)
    pending = migrator.pending_migrations

    display_migrations pending
  end

  desc "List all migrations."
  task :migrations => :environment do
    require 'cassanity/migrator'

    keyspace = Cassanity::Client.new[:my_app]
    migrations_path = Rails.root.join('db', 'migrate')

    migrator = Cassanity::Migrator.new(keyspace, migrations_path)
    display_migrations migrator.migrations
  end

  def display_migrations(migrations)
    max_size = migrations.map(&:name).map(&:size).max + 1
    migrations.each do |migration|
      display_migration migration, size: max_size
    end
  end

  def display_migration(migration, options = {})
    size = options[:size] || migration.name.size
    puts "- #{migration.name.ljust(size)} #{migration.version}"
  end

  desc "Create the keyspace"
  task :create => :environment do
    keyspace = Cassanity::Client.new[:my_app]

    unless keyspace.exists?
      puts "Creating keyspace #{keyspace.name}"
      keyspace.create
    end
  end

  desc "Drop the keyspace"
  task :drop => :environment do
    keyspace = Cassanity::Client.new[:my_app]

    if keyspace.exists?
      puts "Dropping keyspace #{keyspace.name}"
      keyspace.drop
    end
  end
end

I think it would be good to use database.yml or some config to pass keyspace creation arguments. RF and strategy are highly dependent upon environment.