AWS CloudFormation SNS Subscription

AWS CloudFormation SNS Subscription.json

{
  "AWSTemplateFormatVersion": "2010-09-09",
  "Resources": {
    "Topic": {
      "Type": "AWS::SNS::Topic",
      "Properties": {
      }
    },
    "Queue": {
      "Type": "AWS::SQS::Queue",
      "Properties": {
      }
    },
    "Subscription": {
      "Type": "Custom::TopicSubscription",
      "DependsOn": ["FunctionTopicSubscription"],
      "Properties": {
        "ServiceToken": { "Fn::GetAtt": ["FunctionTopicSubscription", "Arn"] },
        "TopicArn": { "Ref": "Topic" },
        "Endpoint": { "Fn::GetAtt": [ "Queue", "Arn" ] },
        "Protocol": "sqs"
      }
    },
    "FunctionTopicSubscription": {
      "Type": "AWS::Lambda::Function",
      "DependsOn": ["LambdaExecutionRole"],
      "Properties": {
        "Handler": "index.handler",
        "Role": { "Fn::GetAtt": ["LambdaExecutionRole", "Arn"] },
        "Code": {
          "ZipFile":  { "Fn::Join": ["\n", [
            "var response = require('cfn-response');",
            "exports.handler = function(event, context) {",
            "  console.log('REQUEST RECEIVED:\\n', JSON.stringify(event));",
            "  var responseData = {};",
            "  if (event.RequestType == 'Delete') {",
            "    var subscriptionArn = event.PhysicalResourceId;",
            "    var aws = require('aws-sdk');",
            "    var sns = new aws.SNS();",
            "    sns.unsubscribe({SubscriptionArn: subscriptionArn}, function(err, data) {",
            "      if (err) {",
            "          responseData = {Error: 'Failed to unsubscribe from SNS Topic'};",
            "          response.send(event, context, response.FAILED, responseData);",
            "      } else {",
            "          response.send(event, context, response.SUCCESS, data, data.SubscriptionArn);",
            "      }",
            "    });",
            "    return;",
            "  }",
            "  if (event.RequestType == 'Create' || event.RequestType == 'Update') {",
            "    var topicArn = event.ResourceProperties.TopicArn;",
            "    var endpoint = event.ResourceProperties.Endpoint;",
            "    var protocol = event.ResourceProperties.Protocol;",
            "    if (topicArn && endpoint && protocol) {",
            "      var aws = require('aws-sdk');",
            "      var sns = new aws.SNS();",
            "      sns.subscribe({TopicArn: topicArn, Endpoint: endpoint, Protocol: protocol}, function(err, data) {",
            "        if (err) {",
            "          responseData = {Error: 'Failed to subscribe to SNS Topic'};",
            "          console.log(responseData.Error + ':\\n', err);",
            "          response.send(event, context, response.FAILED, responseData);",
            "        } else {",
            "          response.send(event, context, response.SUCCESS, data, data.SubscriptionArn);",
            "        }",
            "      });",
            "    } else {",
            "      responseData = {Error: 'Missing one of required arguments'};",
            "      console.log(responseData.Error);",
            "      response.send(event, context, response.FAILED, responseData);",
            "    }",
            "  }",
            "};"
          ]]}
        },
        "Runtime": "nodejs",
        "Timeout": "30"
      }
    },
    "LambdaExecutionRole": {
      "Type": "AWS::IAM::Role",
      "Properties": {
        "AssumeRolePolicyDocument": {
          "Version": "2012-10-17",
          "Statement": [{
              "Effect": "Allow",
              "Principal": {"Service": ["lambda.amazonaws.com"]},
              "Action": ["sts:AssumeRole"]
          }]
        },
        "Path": "/",
        "Policies": [{
          "PolicyName": "DescribeStack",
          "PolicyDocument": {
            "Version": "2012-10-17",
            "Statement": [{
                "Effect": "Allow",
                "Action": ["logs:CreateLogGroup","logs:CreateLogStream","logs:PutLogEvents"],
                "Resource": "arn:aws:logs:*:*:*"
            }, {
                "Effect": "Allow",
                "Action": [
                  "sns:Subscribe",
                  "sns:Unsubscribe"
                ],
                "Resource": { "Ref": "Topic" }
            }]
          }
        }]
      }
    }
  }
}