How to export data to CSV and upload to a separate FTP site from Heroku?

Question

I have some data to export from DB and save as CSV file, and then upload to an FTP server. The site is hosted on Heroku and I understand that you can only write to the tmp (or log?) directories.

This works great on my local machine, but does not work on Heroku.

Here's my rake task:

require 'csv' 
require 'net/ftp'

task :export_data => :environment do
  path = "tmp/" 
  filename = 'test_' + Date.today.to_s + '.dat' 

  messages = Message.where( :foo => bar) 
  CSV.open(path + filename, "wb", :col_sep => '|') do |csv| 

    messages.each do |m| 
      csv << [m.id.to_s, m.name] 
      puts "Processing message " + m.id.to_s 
    end 
  end 

  puts "Uploading " + filename 
  ftp = Net::FTP.new('ftp.hostname.com') 
  ftp.login(user = "******", passwd = "*******") 
  ftp.puttextfile(path + filename, filename) 
  ftp.quit() 

  puts "Finished." 
end

There are 2 issues:

Q1. It is incredibly slow to iterate through the records. 5 minutes for 200. I don't know if this will be usable.

Q2. The ftp has an error and crashes. It starts to put the file on the FTP server, but does not write any data to it. It is an empty file. The log reads:

Starting process with command `rake jobs:work`
2011-10-17T21:17:11+00:00 app[worker.1]: (in /app)
2011-10-17T21:17:13+00:00 heroku[worker.1]: State changed from starting to up
2011-10-17T21:17:13+00:00 app[worker.1]: rake aborted!
2011-10-17T21:17:13+00:00 app[worker.1]: Don't know how to build task 'jobs:work'
2011-10-17T21:17:13+00:00 app[worker.1]: /usr/ruby1.9.2/lib/ruby/1.9.1/rake.rb:1720:in `[]'
2011-10-17T21:17:13+00:00 app[worker.1]: /usr/ruby1.9.2/lib/ruby/1.9.1/rake.rb:2040:in `invoke_task'
2011-10-17T21:17:13+00:00 app[worker.1]: /usr/ruby1.9.2/lib/ruby/1.9.1/rake.rb:2019:in `block (2 levels) in top_level'
2011-10-17T21:17:13+00:00 app[worker.1]: /usr/ruby1.9.2/lib/ruby/1.9.1/rake.rb:2019:in `each'
2011-10-17T21:17:13+00:00 app[worker.1]: /usr/ruby1.9.2/lib/ruby/1.9.1/rake.rb:2019:in `block in top_level'
2011-10-17T21:17:13+00:00 app[worker.1]: /usr/ruby1.9.2/lib/ruby/1.9.1/rake.rb:2058:in `standard_exception_handling'
2011-10-17T21:17:13+00:00 app[worker.1]: /usr/ruby1.9.2/lib/ruby/1.9.1/rake.rb:2013:in `top_level'
2011-10-17T21:17:13+00:00 app[worker.1]: /usr/ruby1.9.2/lib/ruby/1.9.1/rake.rb:1992:in `run'
2011-10-17T21:17:13+00:00 app[worker.1]: /usr/ruby1.9.2/bin/rake:31:in `<main>'
2011-10-17T21:17:13+00:00 heroku[worker.1]: Process exited
2011-10-17T21:17:14+00:00 heroku[worker.1]: State changed from up to crashed

Is there is an issue with the file not being available or some other issue with the file system? Works on local machine.

Any ideas?

Thanks.

Answer 1

Answers:

Q1: It's not slow. It only looks slow because the slow part is outputting to the console.

Q2: FTP was fixed by setting ftp.passive = true

Answer 2

The answer is in

2011-10-17T21:17:13+00:00 app[worker.1]: Don't know how to build task 'jobs:work'

For some reason, your Rakefile isn't aware of jobs:work. Considering that this is a delayed_job task, are you sure you've covered every step of the delayed_job installation properly?

Have you tried this locally in production mode?