engineyard_redis_to_s3.rb

# backup redis databases to s3 on the engineyard platform

require 'zlib'
require 'rubygems'
require 'crack/json'
require 'aws/s3'

class Redis2S3

  DATABASE = '/db/redis/redis_state.rdb'
  CREDENTIALS_FILE = '/etc/chef/dna.json'
  BACKUPS_TO_KEEP = 5
      
  def self.run
    @config = Crack::JSON.parse(File.read(CREDENTIALS_FILE))

    @app_name = @config['environment']['name']
    
    AWS::S3::Base.establish_connection!(
      :access_key_id     => @config['aws_secret_id'],
      :secret_access_key => @config['aws_secret_key']
    )

    # There's a few buckets; we want the ey_backup bucket
    db_backup_bucket = AWS::S3::Service.buckets.detect {|b| b.instance_variable_get(:@attributes)["name"].match(/ey-backup/)}
    
    file_name = "#{@app_name}_#{Time.now.utc.iso8601}.rdb.gz"
      
    # open the file and gzip it
    File.open("/tmp/#{file_name}", 'w') do |file|
      gz = Zlib::GzipWriter.new(file)
      gz.write File.open(DATABASE).read
      gz.close
    end  
    
    # open the gzip and upload it to s3
    AWS::S3::S3Object.store(file_name, open("/tmp/#{file_name}"), db_backup_bucket.name)
       
    # now clear out old backups
    app_backups = db_backup_bucket.objects.select {|o| o.path.match(/#{@app_name}_.*\.rdb.gz/) }
    
    if app_backups.size > BACKUPS_TO_KEEP
      oldest_backup = app_backups.sort_by {|o| Time.parse(o.about["last-modified"]).to_i }.first
      oldest_backup = oldest_backup.key.gsub(/^.*?\//, '')
      AWS::S3::S3Object.delete oldest_backup, db_backup_bucket.name
    end
    
   end

end


Redis2S3.run