Getting Error: 'No connection pool for ActiveRecord::Base' when generating the devise_token_auth generator inside an Rails Engine

[abhilashak]

I have an Rails Engine in my app (authentication_manager). I tried to implement this gem inside my engine. So I added this gem inside the engines Gemfile and installed it.

But I am getting the following error:
No connection pool for ActiveRecord::Base (ActiveRecord::ConnectionNotEstablished)

I am using postgresql and all configuration is correct. And I tried devise and generated it inside this engine and not found any issue.

vagrant@vagrant-ubuntu-trusty-64:~/my-app/components/authentication_manager$ rails g devise_token_auth:install User auth
create config/initializers/devise_token_auth.rb
create db/migrate/20160324104352_devise_token_auth_create_user.rb
/home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/activerecord-4.2.6/lib/active_record/connection_adapters/abstract/connection_pool.rb:570:in retrieve_connection': No connection pool for ActiveRecord::Base (ActiveRecord::ConnectionNotEstablished) from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/activerecord-4.2.6/lib/active_record/connection_handling.rb:113:inretrieve_connection'
from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/activerecord-4.2.6/lib/active_record/connection_handling.rb:87:in connection' from /home/vagrant/.rbenv/versions/2.2.1/gemsets/my-app-authentication-manager/gems/devise_token_auth-0.1.37/lib/generators/devise_token_auth/install_generator.rb:151:indatabase_name'
from **/home/vagrant/.rbenv/versions/2.2.1/gemsets/my-app-authentication-manager/gems/devise_token_auth-0.1.37/lib/generators/devise_token_auth/install_generator.rb:135:in postgres?'** from /home/vagrant/.rbenv/versions/2.2.1/gemsets/my-app-authentication-manager/gems/devise_token_auth-0.1.37/lib/generators/devise_token_auth/install_generator.rb:131:in json_supported_database?'
from (erb):43:inmigration_template' from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/2.2.0/erb.rb:863:in eval'
from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/2.2.0/erb.rb:863:inresult' from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/railties-4.2.6/lib/rails/generators/migration.rb:64:in block in migration_template'
from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/actions/create_file.rb:53:incall' from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/actions/create_file.rb:53:in render'
from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/actions/create_file.rb:62:inblock (2 levels) in invoke!' from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/actions/create_file.rb:62:in open'
from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/actions/create_file.rb:62:inblock in invoke!' from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/actions/empty_directory.rb:116:in call'
from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/actions/empty_directory.rb:116:ininvoke_with_conflict_check' from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/actions/create_file.rb:60:in invoke!'
from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/actions.rb:94:inaction' from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/railties-4.2.6/lib/rails/generators/migration.rb:34:in create_migration'
from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/railties-4.2.6/lib/rails/generators/migration.rb:63:inmigration_template' from /home/vagrant/.rbenv/versions/2.2.1/gemsets/my-app-authentication-manager/gems/devise_token_auth-0.1.37/lib/generators/devise_token_auth/install_generator.rb:18:in copy_migrations'
from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/command.rb:27:inrun' from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/invocation.rb:126:in invoke_command'
from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/invocation.rb:133:inblock in invoke_all' from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/invocation.rb:133:in each'
from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/invocation.rb:133:inmap' from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/invocation.rb:133:in invoke_all'
from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/group.rb:232:indispatch' from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/thor-0.19.1/lib/thor/base.rb:440:in start'
from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/railties-4.2.6/lib/rails/generators.rb:157:ininvoke' from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/railties-4.2.6/lib/rails/commands/generate.rb:13:in <top (required)>'
from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/railties-4.2.6/lib/rails/engine/commands.rb:19:inrequire' from /home/vagrant/.rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/railties-4.2.6/lib/rails/engine/commands.rb:19:in <top (required)>'
from bin/rails:12:inrequire' from bin/rails:12:in

'

[kolyastepanets]

+1

[kopchak]

+1

[kolyastepanets]

If it helps anyone, you can resolve it by manual creating migration file, add routes, add all stuff that generator do.

[abhilashak]

This bug comes from the devise_token_auth gem where the gem checks the database is Postgres or not in 'postgres?' method.
/home/vagrant/.rbenv/versions/2.2.1/gemsets/my-app-authentication-manager/gems/devise_token_auth-0.1.37/lib/generators/devise_token_auth/install_generator.rb

So I just done a monkey patching inside the method and returned true (just say 'yes' to postgres? method, because I am using postgres). And run the generator again.

Hope this will be soon solved by the authors of 'devise_token_auth' gem.

[zachfeldman]

Sounds like we have a proposed solution here, so closing for now.