```ruby
#!/usr/bin/env ruby
#
# This handler assumes it runs on an ec2 instance with an iam role
# that has permission to send to the sns topic specified in the config.
# This removes the requirement to specify an access key and secret access key.
# See http://docs.aws.amazon.com/IAM/latest/UserGuide/WorkingWithRoles.html
#
# Requires the aws-sdk gem.
#
# Setting required in sns.json
#   topic_are  :  The arn for the destination sns topic
#
# Released under the same terms as Sensu (the MIT license); see LICENSE
# for details

require 'rubygems' if RUBY_VERSION < '1.9.0'
require 'sensu-handler'
require 'aws-sdk'

class SnsNotifier < Sensu::Handler
  def topic_arn
    settings['sns']['topic_arn']
  end

  def event_name
    "#{@event['client']['name']}/#{@event['check']['name']}"
  end

  def message
    @event['check']['notification'] || @event['check']['output']
  end

  def handle
    sns = AWS::SNS.new

    t = sns.topics[topic_arn]

    if @event['action'].eql?("resolve")
      t.publish("RESOLVED - [#{event_name}] - #{message}.")
    else
      t.publish("ALERT - [#{event_name}] - #{message}.")
    end
  rescue Exception => e
    puts "Exception occured in SnsNotifier: #{e.message}", e.backtrace
  end
end
```

Add region option for AWS config
user
```ruby
#!/usr/bin/env ruby
#
# This handler assumes it runs on an ec2 instance with an iam role
# that has permission to send to the sns topic specified in the config.
# This removes the requirement to specify an access key and secret access key.
# See http://docs.aws.amazon.com/IAM/latest/UserGuide/WorkingWithRoles.html
#
# Requires the aws-sdk gem.
#
# Setting required in sns.json
#   topic_are  :  The arn for the destination sns topic
#
# Released under the same terms as Sensu (the MIT license); see LICENSE
# for details

require 'rubygems' if RUBY_VERSION < '1.9.0'
require 'sensu-handler'
require 'aws-sdk'

class SnsNotifier < Sensu::Handler
  def topic_arn
    settings['sns']['topic_arn']
  end
  
  def region
    settings['sns']['region'] || 'us-east-1'
  end

  def event_name
    "#{@event['client']['name']}/#{@event['check']['name']}"
  end

  def message
    @event['check']['notification'] || @event['check']['output']
  end

  def handle
    AWS.config(:region => region)
    
    sns = AWS::SNS.new

    t = sns.topics[topic_arn]

    if @event['action'].eql?("resolve")
      t.publish("RESOLVED - [#{event_name}] - #{message}.")
    else
      t.publish("ALERT - [#{event_name}] - #{message}.")
    end
  rescue Exception => e
    puts "Exception occured in SnsNotifier: #{e.message}", e.backtrace
  end
end
```
assistant