AWS SNS Sample code.

_sns_description

Notes on how to use AWS SNS:

1.  Subscribe an HTTP endpoint (i.e. http://myhost/sns_endpoint) on AWS Console
2.  AWS will send subscription confirmation right away
3.  SNS_controller responds to subscription confirmation by sending confirmation using Fog.  
4.  Once AWS is happy, you can start sending notifications to your end point via SNS. 

sns_confirmation.rb

class SNSConfirmation
  def self.confirm(arn, token)
    Rails.logger.debug "#{Figaro.env.aws_access_key} wheee"
    sns = Fog::AWS::SNS.new(
                               aws_access_key_id: Figaro.env.aws_access_key,
                               aws_secret_access_key: Figaro.env.aws_secret_access_key
                             )
    sns.confirm_subscription(arn, token)
  end
end

sns_controller.rb

class SnsController < ApplicationController

  def sns_endpoint
    notification = Hashie::Mash.new JSON.parse(request.raw_post)
    case notification.Type
      when "SubscriptionConfirmation"
        SNSConfirmation.confirm(notification.TopicArn, notification.Token)
      when "Notification"
        SNSNotificationModel.create(:msg notification.Message)
      else
        Rails.logger.error "Unknown notification type #{notification.Type}"
    end

    render nothing: true
  end
end

sns_controller_spec.rb

require 'spec_helper'

describe SnsController do
  describe "confirmation" do
    let(:confirmation_raw_json) { '{
            "Type" : "SubscriptionConfirmation",
            "MessageId" : "33444d09-1ca3-442f-a736-c1848ccbfcd9",
            "TopicArn" : "arn:aws:sns:us-east-1:123456789012:MyTopic",
            "Token" : "2336412f37fb687f5d51e6e241d164b14f9e81c6c9aa29262ce3fb4117fb80948fc247162d9d2b1b74c51218008d9b17aa760450f775d3dc0a5bede65011342fd6b520e5404d4e01cc29f5ba5dcc07e91498edde82b7401f7a62cc272416eed80929ae7d3c5395ceb6730fa5a41d0029d0bae9128822d25c7b6ab5b5739c9f61",
            "SubscribeURL" : "https://sns.us-east-1.amazonaws.com/?Action=ConfirmSubscription&TopicArn=arn:aws:sns:us-east-1:123456789012:MyTopic&Token=2336412f37fb687f5d51e6e241d09c805a5a57b30d712f794cc5f6a988666d92768dd60a747ba6f3beb71854e285d6ad02428b09ceece29417f1f02d609c582afbacc99c583a916b9981dd2728f4ae6fdb82efd087cc3b7849e05798d2d2785c03b0879594eeac82c01f235d0e717736"}'
    }
    it "dispatches subscription confirmation" do
      h = JSON.parse(confirmation_raw_json)
      SNSConfirmation.should_receive(:confirm).with(h['TopicArn'], h['Token'])
      @request.env['RAW_POST_DATA'] = confirmation_raw_json
      post :sns_endpoint, {}
    end
  end

  describe "notification" do
    let(:notification_raw_json) {
      '{"Type" : "Notification",
        "Message" :  "{ \"uuid\": \"12341234uu\",  \"status\": \"Processing\" }" }'
    }

    it "dispatches notification" do
      h = JSON.parse(notification_raw_json)
      pst = mock_model(ProcessStatus)
      @request.env['RAW_POST_DATA'] = notification_raw_json
      ProcessStatus.should_receive(:where).with( uuid: "12341234uu" ).and_return(pst)
      pst.should_receive(:status=)
      pst.should_receive(:save!)
      post :sns_endpoint, {}
    end
  end
end

Thank you, this was extremely helpful!