Simple cron job for Heroku to back up your database to S3 and remove stale database sessions.

cron.rb

task :cron => :environment do

  # removes day old sessions from the database
  puts "====> Removing stale sessions from the database…”
  Rake::Task['db:sessions:clear_stale'].execute
  
  # run the following tasks on sunday
  if Time.now.wday == 0
    # backs up the database to S3
    puts "====> Backing up database to S3…”
    Rake::Task['db:backup'].invoke
  end
  
end

db_backup.rb

namespace :db do

  desc "Backs up the database to S3"
  task :backup => :environment do 
    
    puts "Back up started on #{Time.now}..."    
    
    PATH_TO_CLIENT_BACKUP = 'specific-path-in-bucket'

    puts "Pulling database..."    
    backup_name = "ew#{Time.now.to_i}.db" 
    backup_path = "tmp/#{backup_name}" 
    YamlDb.dump backup_path 
    
    puts "Compressing database..." 
    'gzip #{backup_path}' 
    backup_name += ".gz" 
    backup_path = "tmp/#{backup_name}" 
    
    puts "Uploading #{backup_name} to S3..." 
    
    puts "Connecting to AWS..."
    config = YAML.load(File.open("#{RAILS_ROOT}/config/s3.yml"))[RAILS_ENV]
    AWS::S3::Base.establish_connection!( 
      :access_key_id => config['access_key_id'], 
      :secret_access_key => config['secret_access_key'] 
    )
    
    puts "Finding S3 bucket..." 
    begin 
      bucket = AWS::S3::Bucket.find config['bucket'] 
    rescue AWS::S3::NoSuchBucket 
      AWS::S3::Bucket.create config['bucket'] 
      bucket = AWS::S3::Bucket.find config['bucket'] 
    end
    
    puts "Storing backup database on S3..." 
    AWS::S3::S3Object.store backup_name, 
      File.read(backup_path), 
      bucket.name + PATH_TO_CLIENT_BACKUP, 
      :content_type => 'application/x-gzip' 
    
      puts "Backup ended on #{Time.now}" 
  end
  
end

db_session_clear_stale.rb

namespace :db do
  namespace :sessions do
    desc "Clears stale (e.g. day old) sessions"
    task :clear_stale => :environment do
      session_count = ActiveRecord::SessionStore::Session.delete_all(['updated_at < ?', 1.day.ago])
      puts "#{session_count} sessions removed..."
    end
  end
end