Rake tasks are missing when installed in Rails via another gem

[wscourge]

Problem

I have a gem with the following code:

# whatever/whatever.gemspec
Gem::Specification.new do |spec|
  # ...
  # ...
  spec.files = Dir['{app,lib}/**/*', 'CHANGELOG.md', 'LICENSE.md', 'README.md']
  spec.add_dependency('rails')
  spec.add_dependency('data_migrate')
  # ...
end

After bundling it into my brand-new Rails app:

# brand_new_rails_app/Gemfile
# ...
# ...
gem 'whatever', path: 'path/to/whatever'
# ...
# ...

and running rails -T in the command line, I do not see the rake tasks available via the data_migrate gem. Running rails data:migrate produces the following:

Don't know how to build task 'data:migrate' (See the list of available tasks with rails --tasks)

Additionally, what seems weird and makes me think that this is rake-tasks specific, the data_migrate generator is available - running rails g --help lists it as follows:

# ...
DataMigration:
  data_migration
# ...

Question

Any of you guys have an idea what am I doing wrong? The problem is obviously on my side, cause when 'data_migrate' is added directly to the brand new rails app, the tasks are available.

Related SO questions

I went through all of the stuff below with no avail. As you can see:

1. I use the add_dependency, not the add_development_dependency
2. I install my 'whatever' gem outside any of the groups, so it is available for every Rails.env
3. I include files using /**/* wildcard (without extension Dir['{app,lib}/**/*']) - I don't think it is actually relevant, as tasks come from the data_migrate gem dependency, not my gem.

---

Including rake tasks in gems
Why are db tasks missing from rake?
Rake tasks inside gem not being found
Why is this gem not adding rake tasks to a rails app?

I'll appreciate any help, thanks in advance.

[wscourge]

I have also tried using add_runtime_dependency with no avail

[kaka-ruto]

This works for me when I add the gem "data_migrate" into the gem's Gemfile and not the .gemspec

However, the task names are preceded by an app namespace

rake -T data
rake app:data:abort_if_pending_migrations          # Raises an error if there are pending data migrations
rake app:data:dump                                 # Create a db/data_schema.rb file that stores the current data version
rake app:data:forward                              # Pushes the schema to the next version (specify steps w/ STEP=n)
rake app:data:migrate                              # Migrate data migrations (options: VERSION=x, VERBOSE=false)
rake app:data:migrate:down                         # Runs the "down" for a given migration VERSION
rake app:data:migrate:redo                         # Rollbacks the database one migration and re migrate up (options: STEP=x, VERSION=x)
rake app:data:migrate:status                       # Display status of data migrations
rake app:data:migrate:up                           # Runs the "up" for a given migration VERSION
rake app:data:rollback                             # Rolls the schema back to the previous version (specify steps w/ STEP=n)
rake app:data:schema:load                          # Load data_schema.rb file into the database
rake app:data:version                              # Retrieves the current schema version number for data migrations
rake app:db:abort_if_pending_migrations:with_data  # Raises an error if there are pending migrations or data migrations
rake app:db:forward:with_data                      # Pushes the schema to the next version (specify steps w/ STEP=n)
rake app:db:migrate:down:with_data                 # Runs the "down" for a given migration VERSION
rake app:db:migrate:redo:with_data                 # Rollbacks the database one migration and re migrate up (options: STEP=x, VERSION=x)
rake app:db:migrate:status:with_data               # Display status of data and schema migrations
rake app:db:migrate:up:with_data                   # Runs the "up" for a given migration VERSION
rake app:db:migrate:with_data                      # Migrate the database data and schema (options: VERSION=x, VERBOSE=false)
rake app:db:rollback:with_data                     # Rolls the schema back to the previous version (specify steps w/ STEP=n)
rake app:db:schema:load:with_data                  # Load both schema.rb and data_schema.rb file into the database
rake app:db:structure:load:with_data               # Load both structure.sql and data_schema.rb file into the database
rake app:db:version:with_data                      # Retrieves the current schema version numbers for data and schema migrations

[jeffktan]

In the Rakefile, I added the following to the bottom to support having rake db:migrate run rake db:migrate:with_data from the root gem directory. (Don't forget to setup your Rakefile similar to this https://github.com/twinge/questionnaire_engine/blob/engine2/Rakefile)

# Adds data_migrate rake tasks to root
spec = Gem::Specification.find_by_name 'data_migrate'
load "#{spec.gem_dir}/tasks/databases.rake"
namespace :db do
  # Adds extra alias to support data_migrate tasks ran from root
  task :_dump => ["app:db:_dump"]
  # Create alias to run data migrations along with the normal db migrations
  task :migrate => ["db:migrate:with_data"]
end

In the engine.rb file, don't forget to configure the db and data configurations:

    # include migrations in enclosing app
    # https://tanzu.vmware.com/content/blog/leave-your-migrations-in-your-rails-engines
    initializer :append_migrations do |app|
      unless app.root.to_s.match root.to_s
        config.paths['db/migrate'].expanded.each do |expanded_path|
          app.config.paths['db/migrate'] << expanded_path
        end
      end
    end

    # include data migrations in parent app
    initializer :data_migrations do |app|
      ::DataMigrate.configure do |data_migrate|
        default_path = ::DataMigrate::Config.new.data_migrations_path
        data_migrate.data_migrations_path = [root.join('db', 'data')]
      end
    end

In the parent app, I had to run the rake db:load_config task before running rake db:migrate:with_data as it was missing it so it didn't pick up the gem's db/migrate files. (Maybe someone can add a PR to make sure rake db:migrate:with_data runs the load_config task like how Rails does it with rake db:migrate)
I added the following to the Rakefile in the parent app so that rake db:migrate would run all the db and data migrations in the parent app as well as the gem.

namespace :db do
  task :migrate => ["db:load_config", "db:migrate:with_data"]
end