database_dumping.rake

namespace :db do
  desc 'Dumps the database to db/backups'
  task :dump, [:backup_name] => :environment do |_task, args|
    params = gather_required_data(args)

    cmd = [
      'pg_dump',
      '-F c',
      '-v',
      '-h', params[:host],
      '-d', params[:database],
      '-f',
      Rails.root.join('db', 'backups', "#{params[:backup_name]}_#{params[:database]}.psql")
    ].join(' ')

    puts cmd
    exec cmd
  end

  desc 'Restores the database from db/backups'
  task :restore, [:backup_name] => :environment do |_task, args|
    params = gather_required_data(args)

    cmd = [
      'pg_restore',
      '-F c',
      '-v',
      '-h', params[:host],
      '-d', params[:database],
      Rails.root.join('db', 'backups', "#{params[:backup_name]}_#{params[:database]}.psql")
    ].join(' ')

    Rake::Task['db:drop'].invoke
    Rake::Task['db:create'].invoke

    puts cmd
    exec cmd
  end

  private

  def gather_required_data(args)
    with_config do |_app, host, database, _user|
      {
        backup_name: args.backup_name,
        host:        host,
        database:    database
      }.tap do |params|
        return params if params.values.reject(&:blank?).count == 3
      end
    end

    raise 'Missing required information. You need to pass in a backup name and your database.yml needs a host and a database name for this environment.'
  end

  def with_config
    yield Rails.application.class.parent_name.underscore,
    ActiveRecord::Base.connection_config[:host],
    ActiveRecord::Base.connection_config[:database],
    ActiveRecord::Base.connection_config[:username]
  end
end