"Errno::EMFILE: Too many open files" with local images on create - ruby-on-rails

Question

On create of an object in Rails, I want to automatically assign it a stock image from the assets directory which can be overwritten later by a user.
As a result, I execute the following private method upon creation of the object:
def save_stock_image
image_path = Dir.glob(<list-of-images-from-directory>).sample
File.open(image_path) do |file|
self.image = file
self.save!
end
end
However, after 6 RSpec tests, I begin to receive the following error:
Failure/Error: let(:object) { create(:object) }
Errno::EMFILE:
Too many open files - /tmp/16020130822-36578-q8j9v9.jpg
# ./app/models/object.rb:502:in `block in save_stock_image'
# ./app/models/object.rb:501:in `open'
# ./app/models/object.rb:501:in `save_stock_image'
# ./spec/controllers/object_controller_spec.rb:318:in `block (3 levels) in <top (required)>'
# ./spec/controllers/object_controller_spec.rb:344:in `block (4 levels) in <top (required)>'
The above error is on ~40 of 60 tests. I've looked at a few SO questions, as well as https://github.com/thoughtbot/paperclip/issues/1122 and https://github.com/thoughtbot/paperclip/issues/1000. The closest answer I could find was to ensure the file descriptor was closing. Before I used File.open in the block, I explicitly closed the file with file.close - this didn't work either.
Something obvious that I'm doing wrong? Is there a better way to accomplish what I'm trying to do?
UPDATE
It looks like it has something to do with the temporary files which Paperclip creates before they are uploaded to S3. Is there something with closing those tempfiles that I'm missing?

Answer 1

Just ran into this myself. It looks like the master branch has a fix. See my comments here:
https://github.com/thoughtbot/paperclip/issues/1326?source=cc

Answer 2

If this is a development/test environment and you want a quick resolution.
Try to identify resque process id, kill it and restart the resque server.
Additionally you may try the below
Redis.current.client.reconnect
$redis = Redis.current

Answer 3

Just ran into this and the latest code didn't help me. So, I delegated the work of closing those temp files to the OS by spawning a child process:
def save_stock_image
ActiveRecord::Base.connection.disconnect!
Proces.fork do
image_path = Dir.glob(<list-of-images-from-directory>).sample
File.open(image_path) do |file|
self.image = file
self.save!
end
end
Process.wait
ActiveRecord::Base.establish_connection
end
Also, consider placing a timeout on the Process.wait like suggested here: Waiting for Ruby child pid to exit