Backup script to take a snapshot of the database and upload to Rockspace Cloud Files

backup.rake

# Backup script to take a snapshot of the database and upload to Rockspace Cloud Files 
# also manages the no of backups to keep.
# 
# Note: You will require a Rackspace Cloud account, more details @ http://www.rackspace.com/cloud/
#
# -------------
# Configuration
# -------------
# The script uses the database.yml for configuration. Backup database details should be 
# provided for the appropriate environment.
#
# ---------------------
# Sample Configuration
# ---------------------
# production:
#  adapter: mysql 
#  host: db_host
#  database: database_name
#  username: db_user
#  backup:
#    adapter: mysql
#    host: db_host
#    database: db_name
#    username: root
#    cloud_user: rackspace_cloud_user_id
#    cloud_key: api_key_provided_by_rackspace
#    cloud_container: container_to_store
#    keep_backups: no_of_backups_to_keep_in_the_container
#
# -----------------
# Gem Dependencies
# -----------------
#   rails 2.3.8
#   cloudfiles 

namespace :db do
  desc "Creates a snapshot of the database under tmp/backups/db and uploads to Rackspace Cloud"
  task :backup, :needs => :environment do
    
    BACKUP_DIR_PATH = File.expand_path(File.join(RAILS_ROOT,"tmp","backups","db"))
    
    # Create Directories if they don't exist
    FileUtils.mkpath BACKUP_DIR_PATH unless File.directory?(BACKUP_DIR_PATH) 
    
    # Check for lock file to ensure just one backup is being taken at a time
    lock_file = File.expand_path(File.join(BACKUP_DIR_PATH,".lock"))
    raise "There is a backup process being run or did not finish properly, check #{BACKUP_DIR_PATH}" if File.exists? lock_file
        
    # Create the lock file and write the process id, should delete this once the backup is done
    File.open(lock_file, 'w') {|f| f.write(Process.pid) }
  
    # Check if mysqldump exists in the path
    mysqldump_path = nil
    ENV['PATH'].split(':').each {|folder| mysqldump_path = folder + "/mysqldump" if File.exists?(folder+'/mysqldump')}
    raise "mysqldump executable not found in path" if mysqldump_path.blank?
    
    # Fetch Database details from database.yml
    db_config = Rails::Configuration.new.database_configuration[RAILS_ENV]["backup"]
    raise "backup DB is not defined in database config" if db_config.blank?
        
    # Consutrcting the mysqldump command
    command = "#{mysqldump_path} --opt "
    command += "-h #{db_config['host']} " unless db_config['host'].blank?
    command += "-P #{db_config['port']} " unless db_config['port'].blank?
    command += "-u #{db_config['username']} " unless db_config['username'].blank?
    command += "-p#{db_config['password']} " unless db_config['password'].blank?
    command += "#{db_config['database']} "
    
    file_name = Time.now.strftime("#{db_config['database']}-%d-%B-%YT%H%M.sql")
    file_path = File.expand_path(File.join(BACKUP_DIR_PATH,file_name))
    command += "> #{file_path}"
    
    
    puts "starting backup, writing to #{file_path}"
    system command # Run the command
    puts "backup complete, wrote to #{file_path}"
    
    # Upload to the cloud
    puts "starting upload"
    cloud_files = CloudFiles::Connection.new(:username => db_config['cloud_user'], :api_key => db_config['cloud_key'])
    container = cloud_files.container(db_config['cloud_container'])
    obj = container.create_object(file_name)
    obj.write File.open(file_path,'rb')
    puts "upload complete"
    
    # Cleanup
    File.delete(file_path)
    File.delete(lock_file)
    
    # Number of files should not exceed the number specified @ keep_backups
    if container.objects.count > db_config['keep_backups']
      objects = container.objects_detail # => Fetches all the object details
      no_objs_to_delete = objects.size - db_config['keep_backups'] - 1
      sorted_objects = objects.sort_by {|obj| obj[1][:last_modified]}
      sorted_objects[0..no_objs_to_delete].each {|obj| container.delete_object obj[0]}
    end
    
  end
end