sns simple example added

Author: vlopatkin

README.md

@@ -105,6 +105,10 @@ Make sure :
 This file you can obtain on Getting Started page inside your IronWorker project (https://hud.iron.io/dashboard).
 * you have specified a valid docker repository name in DOCKER_REPO_NAME variable of _./deploy.env_ file.
 
+## Examples
+
+* [Amazon Simple Notification Service](./examples/sns/README.md)
+
 ## Notes
 ### Windows Users
 

examples/sns/README.md

@@ -0,0 +1,13 @@
+Amazon SNS can be used as a mediator to bypass events from other Amazon Web Services to iron-lambda ([Amazon Simple Storage Service (S3)](http://docs.aws.amazon.com/AmazonS3/latest/dev/ways-to-add-notification-config-to-bucket.html) for example)
+
+To use Amazon SNS as event source to you lambda function you should the following steps:
+
+1. Upload your lambda function with [`iron-lambda deploy`](../../README.md)
+2. On existing SNS topic Create New Subsription with the parameters:
+   * Protocol: HTTPS
+   * Endpoint: The webhook url for the lambda function (the url is located in _Webhook URL_ field on _Code_ page of the worker created for your lambda function)
+3. Request the confirmation of the new subscription. The confirmation is sent to your lambda function. You should be interested in _SubscribeURL_ in the payload. The payload can be viewed on on _Tasks_ page of the worker.
+4. Confirm subscription by either following the _SubscribeURL_ or entring this URL on _Confirm subscription_ dialog in AWS Management Console.
+5. From this point every message published to topic will be sent to the lambda function in `Message` property of `event` parameter. Optionally, you could parse the message to json (see [example](./lambda.js)).
+
+**Note**: For security reason it's desured to validate the incoming message signature. More information can be obtained [here](http://docs.aws.amazon.com/sns/latest/dg/SendMessageToHttp.verify.signature.html)

examples/sns/lambda.js

@@ -0,0 +1,26 @@
+exports.handler = function(event, context) {
+//structure of SNS event see here: http://docs.aws.amazon.com/sns/latest/dg/json-formats.html#http-notification-json
+    console.log("event.Type", event.Type);
+
+    if (event.Type == 'Notification') {
+      var message = JSON.parse(event.Message);
+
+      console.log( "message",  message);
+
+      context.done();
+    }
+    else if (event.Type == 'SubscriptionConfirmation'){
+      console.log( "confimation URL",  event.SubscribeURL);
+
+      context.done();
+    }
+    else if (event.Type == 'UnsubscribeConfirmation'){
+
+      context.done();
+    }
+    else {
+      console.log("unknown event.Type", event.Type);
+
+      context.fail();
+    }
+};

package.json

@@ -18,6 +18,7 @@
     "url" : "https://github.com/vlopatkin/iron-lambda"
   },
   "files": [
+    "examples",
     "templates",
     "app.js",
     "package.json",