Feature/sns filter policy

examples/2016-10-31/lambda_sns_filter_policy/README.md

@@ -0,0 +1,35 @@
+# Lambda function + Filtered SNS Subscription Example
+
+This example shows you how to create a Lambda function with a SNS event source. 
+
+The Lambda function does not receive all messages published to the SNS topic but only a subset. The messages are filtered based on the attributes attached to
+ the message.
+
+## Running the example 
+
+Deploy the example into your account:
+
+```bash
+# Replace YOUR_S3_ARTIFACTS_BUCKET with the name of a bucket which already exists in your account
+aws cloudformation package --template-file template.yaml --output-template-file template.packaged.yaml --s3-bucket YOUR_S3_ARTIFACTS_BUCKET
+
+aws cloudformation deploy --template-file ./template.packaged.yaml --stack-name sam-example-lambda-sns-filter-policy --capabilities CAPABILITY_IAM
+```
+
+The Lambda function will only receive messages with the attribute `sport` set to `football`.
+
+In the AWS console go to the topic sam-example-lambda-sns-filter-policy and push the Publish to Topic button.
+At the bottom of the Publish page you can add message attributes. Add one attribute:
+- key: sport
+- Attribute type: String
+- value: football
+
+Enter an arbitrary message body and publish the message.
+In Cloudwatch the log group /aws/lambda/sam-example-lambda-sns-filter-policy-notification-logger appears and the logging contains the message attributes of 
+the received message.
+
+Now publish a couple of other messages with other values for the attribute `sport` or without the attribute `sport`. 
+The Lambda function will not receive these messages.  
+
+## Additional resources
+https://docs.aws.amazon.com/sns/latest/dg/message-filtering.html

examples/2016-10-31/lambda_sns_filter_policy/src/index.js

@@ -0,0 +1,8 @@
+'use strict';
+
+
+exports.handler = async (event, context, callback) => {
+    console.log("Message attributes: " + JSON.stringify(event.Records[0].Sns.MessageAttributes));
+
+    callback(null, "Success");
+};

examples/2016-10-31/lambda_sns_filter_policy/template.yaml

@@ -0,0 +1,24 @@
+AWSTemplateFormatVersion: '2010-09-09'
+Transform: AWS::Serverless-2016-10-31
+Description: Lambda function with SNS filter policy
+Resources:
+  NotificationLogger:
+    Type: AWS::Serverless::Function
+    Properties:
+      CodeUri: ./src
+      Handler: index.handler
+      Runtime: nodejs8.10
+      FunctionName: sam-example-lambda-sns-filter-policy-notification-logger
+      Events:
+        NotificationTopic:
+          Type: SNS
+          Properties:
+            Topic: !Ref Notifications
+            FilterPolicy:
+              sport:
+                - football
+
+  Notifications:
+    Type: AWS::SNS::Topic
+    Properties:
+      TopicName: sam-example-lambda-sns-filter-policy

samtranslator/model/eventsources/push.py

@@ -299,7 +299,8 @@ class SNS(PushEventSource):
     resource_type = 'SNS'
     principal = 'sns.amazonaws.com'
     property_types = {
-            'Topic': PropertyType(True, is_str())
+            'Topic': PropertyType(True, is_str()),
+            'FilterPolicy': PropertyType(False, dict_of(is_str(), list_of(one_of(is_str(), is_type(dict)))))
     }
 
     def to_cloudformation(self, **kwargs):
@@ -315,14 +316,17 @@ def to_cloudformation(self, **kwargs):
             raise TypeError("Missing required keyword argument: function")
 
         return [self._construct_permission(function, source_arn=self.Topic),
-                self._inject_subscription(function, self.Topic)]
+                self._inject_subscription(function, self.Topic, self.FilterPolicy)]
 
-    def _inject_subscription(self, function, topic):
+    def _inject_subscription(self, function, topic, filterPolicy):
         subscription = SNSSubscription(self.logical_id)
         subscription.Protocol = 'lambda'
         subscription.Endpoint = function.get_runtime_attr("arn")
         subscription.TopicArn = topic
 
+        if filterPolicy is not None:
+            subscription.FilterPolicy = filterPolicy
+
         return subscription
 
 

samtranslator/model/sns.py

@@ -1,11 +1,12 @@
 from samtranslator.model import PropertyType, Resource
-from samtranslator.model.types import is_str
+from samtranslator.model.types import is_type, is_str
 
 
 class SNSSubscription(Resource):
     resource_type = 'AWS::SNS::Subscription'
     property_types = {
         'Endpoint': PropertyType(True, is_str()),
         'Protocol': PropertyType(True, is_str()),
-        'TopicArn': PropertyType(True, is_str())
+        'TopicArn': PropertyType(True, is_str()),
+        'FilterPolicy': PropertyType(False, is_type(dict))
     }

samtranslator/validator/sam_schema/schema.json

@@ -619,6 +619,9 @@
       "properties": {
         "Topic": {
           "type": "string"
+        },
+        "FilterPolicy": {
+          "type": "object"
         }
       },
       "required": [

tests/model/eventsources/test_sns_event_source.py

@@ -0,0 +1,50 @@
+from mock import Mock
+from unittest import TestCase
+from samtranslator.model.eventsources.push import SNS
+
+
+class SnsEventSource(TestCase):
+
+    def setUp(self):
+        self.logical_id = 'NotificationsProcessor'
+
+        self.sns_event_source = SNS(self.logical_id)
+        self.sns_event_source.Topic = 'arn:aws:sns:MyTopic'
+
+        self.function = Mock()
+        self.function.get_runtime_attr = Mock()
+        self.function.get_runtime_attr.return_value = 'arn:aws:lambda:mock'
+
+    def test_to_cloudformation_returns_permission_and_subscription_resources(self):
+        resources = self.sns_event_source.to_cloudformation(
+            function=self.function)
+        self.assertEquals(len(resources), 2)
+        self.assertEquals(resources[0].resource_type,
+                          'AWS::Lambda::Permission')
+        self.assertEquals(resources[1].resource_type,
+                          'AWS::SNS::Subscription')
+
+        subscription = resources[1]
+        self.assertEquals(subscription.TopicArn, 'arn:aws:sns:MyTopic')
+        self.assertEquals(subscription.Protocol, 'lambda')
+        self.assertEquals(subscription.Endpoint, 'arn:aws:lambda:mock')
+        self.assertIsNone(subscription.FilterPolicy)
+
+    def test_to_cloudformation_passes_the_filter_policy(self):
+        filterPolicy = {
+            'attribute1': ['value1'],
+            'attribute2': ['value2', 'value3'],
+            'attribute3': {'numeric': ['>=', '100']}
+        }
+        self.sns_event_source.FilterPolicy = filterPolicy
+
+        resources = self.sns_event_source.to_cloudformation(
+            function=self.function)
+        self.assertEquals(len(resources), 2)
+        self.assertEquals(resources[1].resource_type,
+                          'AWS::SNS::Subscription')
+        subscription = resources[1]
+        self.assertEquals(subscription.FilterPolicy, filterPolicy)
+
+    def test_to_cloudformation_throws_when_no_function(self):
+        self.assertRaises(TypeError, self.sns_event_source.to_cloudformation)

tests/translator/input/function_with_sns_event_source_all_parameters.yaml

@@ -0,0 +1,28 @@
+Resources:
+  MyAwesomeFunction:
+    Type: 'AWS::Serverless::Function'
+    Properties:
+      CodeUri: s3://sam-demo-bucket/hello.zip
+      Handler: hello.handler
+      Runtime: python2.7
+
+      Events:
+        NotificationTopic:
+          Type: SNS
+          Properties:
+            Topic: topicArn
+            FilterPolicy:
+              store:
+              - example_corp
+              event:
+              - anything-but: order_cancelled
+              customer_interests:
+              - rugby
+              - football
+              - baseball
+              price_usd:
+              - numeric:
+                - ">="
+                - 100
+
+

tests/translator/output/aws-cn/function_with_sns_event_source_all_parameters.json

@@ -0,0 +1,98 @@
+{
+  "Resources": {
+    "MyAwesomeFunctionNotificationTopic": {
+      "Type": "AWS::SNS::Subscription",
+      "Properties": {
+        "FilterPolicy": {
+          "store": [
+            "example_corp"
+          ],
+          "event": [
+            {
+              "anything-but": "order_cancelled"
+            }
+          ],
+          "customer_interests": [
+            "rugby",
+            "football",
+            "baseball"
+          ],
+          "price_usd": [
+            {
+              "numeric": [
+                ">=",
+                100
+              ]
+            }
+          ]
+        },
+        "Endpoint": {
+          "Fn::GetAtt": [
+            "MyAwesomeFunction",
+            "Arn"
+          ]
+        },
+        "Protocol": "lambda",
+        "TopicArn": "topicArn"
+      }
+    },
+    "MyAwesomeFunctionNotificationTopicPermission": {
+      "Type": "AWS::Lambda::Permission",
+      "Properties": {
+        "Action": "lambda:invokeFunction",
+        "Principal": "sns.amazonaws.com",
+        "FunctionName": {
+          "Ref": "MyAwesomeFunction"
+        },
+        "SourceArn": "topicArn"
+      }
+    },
+    "MyAwesomeFunctionRole": {
+      "Type": "AWS::IAM::Role",
+      "Properties": {
+        "ManagedPolicyArns": [
+          "arn:aws-cn:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"
+        ],
+        "AssumeRolePolicyDocument": {
+          "Version": "2012-10-17",
+          "Statement": [
+            {
+              "Action": [
+                "sts:AssumeRole"
+              ],
+              "Effect": "Allow",
+              "Principal": {
+                "Service": [
+                  "lambda.amazonaws.com"
+                ]
+              }
+            }
+          ]
+        }
+      }
+    },
+    "MyAwesomeFunction": {
+      "Type": "AWS::Lambda::Function",
+      "Properties": {
+        "Code": {
+          "S3Bucket": "sam-demo-bucket",
+          "S3Key": "hello.zip"
+        },
+        "Handler": "hello.handler",
+        "Role": {
+          "Fn::GetAtt": [
+            "MyAwesomeFunctionRole",
+            "Arn"
+          ]
+        },
+        "Runtime": "python2.7",
+        "Tags": [
+          {
+            "Value": "SAM",
+            "Key": "lambda:createdBy"
+          }
+        ]
+      }
+    }
+  }
+}