Table dosen't exists while setting up new application with grape mounted application

Question

I have mounted grape gem over exsting application & in kept grape api related changes in

app >> controller >> api

directory. (which is auto loaded. No code is written for autoloading)

And in that I have code like fetching values form the database table.

module API
  module V1
    class Users < Grape::API
      include API::V1::Defaults

      resource :users do

        desc 'Creates a User'
        params do
          requires :role_id,
            type: Integer,
            values: Role.all.collect { |role| role.id },
            desc: 'Role ID'

Here Role.all getting called while setting up new application, which is doesn't exists yet.

But while setting up new application, when I run "rake db:migrate" it gives table doesn't exists error.

How can I stop auto loading of the "api" folder inside controller while setting up new application so that it will not get called.

Or how can I handle above scenario.

& application.rb file where defined grape

module Api
  class Application < Rails::Application
    config.middleware.use Rack::Cors do
      allow do
        origins '*'
        resource '*', headers: :any, methods: [:get,
          :post, :put, :delete, :options]
      end
    end
  end
end

Thanks in advance.

Hmm if it asks for a missing table role, did you follow all required steps to run app/gem? — Nezir, Oct 03 '18 at 06:19
Yes, used bundle install to run app/gem and it executed successfully. — Akash Kinwad, Oct 03 '18 at 06:25
but maybe gem installation requiring some additional config. steps? Like these steps for Rails https://github.com/ruby-grape/grape — Nezir, Oct 03 '18 at 06:28
I have updated my question, added application.rb file changes where I have included the config changes for the grape — Akash Kinwad, Oct 03 '18 at 06:33
can you try this: https://blog.bigbinary.com/2016/08/29/rails-5-disables-autoloading-after-booting-the-app-in-production.html — Nezir, Oct 03 '18 at 06:44

score 0 · Answer 1 · answered Oct 04 '18 at 06:08

Above problem was solved by using lazy evaluation of the values.

Used proc for grape values

The :values option can also be supplied with a Proc, evaluated lazily with each request.

and reframed code will be as below

module API
  module V1
    class Users < Grape::API
      include API::V1::Defaults

      resource :users do

        desc 'Creates a User'
        params do
          requires :role_id,
            type: Integer,
            values: -> { Role.all.collect { |role| role.id } },
            desc: 'Role ID'

We can also use class methods inside proc to fasten the query.

Table dosen't exists while setting up new application with grape mounted application

1 Answers1