ActiveRecordRedisLock

Exhibit A.

Post:
  id: Int
  title: String
  body: String

User:
  id: Int
  ...

Post.redis_lock(current_user, "create_post") do |p|
  p.create(title: "Blah", body: "Blah blah blah")
end

Exhibit B.

Post.redis_lock(current_user, "create_post") do
  Post.create(title: "Blah", body: "Blah blah blah")
end

Exhibit C.

# (In Controller)
profile, new_job_application = redis_lock(current_user, "attach_new") do
  return [
    ApplicantProfile.create(:phone_number => params[:phone], :user => user),
    JobApplication.create(:job => Job.find(params[:job_id]), :user => user)
  ]
end
render :json => {:saved => profile, :url => employer_portal_job_application_path(new_job_application)}.to_json

Usage

# Gemfile
gem 'active_record_redis_lock', git: "git@github.com:aaronlifton/ActiveRecordRedisLock.git"