nagios check script to check for max age of files in an s3 bucket. written in ruby, requires aws-sdk v2 gem.

check_s3_age.rb

require 'aws-sdk'

CONFIG = {

    # nil to load from env
    :aws_access_key => nil,
    :aws_secret_access_key => nil,
    :aws_region => nil,

    # in seconds
    :warning_age => 86400 * 1,
    :critical_age => 86400 * 2,

    # regex that key must match, nil for all keys.
    # use /pattern/ syntax
    :name_pattern => nil
}


class CheckS3Age

  def initialize
    @debug = ENV['CHECK_S3_AGE_DEBUG'] == 'true'
  end

  def run(args)
    bucket = args[0]

    abort "usage: #{$0} <bucket>" unless bucket

    objects = get_bucket_objects(bucket)
    newest = newest_object(objects.contents)

    puts "newest object was last modified at: #{Time.at newest}" if @debug

    now = Time.now.to_i

    if now - CONFIG[:critical_age] > newest
      puts "CRITICAL - no file newer than #{CONFIG[:critical_age]} seconds ago was found"
      exit 2
    elsif now - CONFIG[:warning_age] > newest
      puts "WARNING - no file newer than #{CONFIG[:warning_age]} seconds ago was found"
      exit 1
    else
      puts "OK - recent file found"
      exit 0
    end
  end

  def api_init
    if CONFIG[:aws_access_key] && CONFIG[:aws_secret_access_key]
      Aws.config[:credentials] = Aws::Credentials.new(CONFIG[:aws_access_key], CONFIG[:aws_secret_access_key])
    end

    Aws.config[:region] = CONFIG[:aws_region] || ENV['AWS_REGION'] || 'us-east-1'

    Aws::S3::Client.new
  end

  def api
    @api ||= api_init
  end

  def get_bucket_objects(bucket)
    api.list_objects({:bucket => bucket})
  end

  def newest_object(objects)
    newest = 0
    objects.each do |obj|
      if CONFIG[:name_pattern]
        next unless obj.key =~ CONFIG[:name_pattern]
      end
      puts "found #{obj.key} last modified at #{obj.last_modified}" if @debug
      if obj.last_modified.to_i > newest
        newest = obj.last_modified.to_i
      end
    end
    newest
  end

end

if __FILE__ == $0
  CheckS3Age.new.run(ARGV)
end