LogListener.yaml

Resources:
    CrashingLambda:
        Type: AWS::Lambda::Function
        Properties: 
          Code:
            ZipFile: >
              exports.handler = function(event, context) {
                 FunctionDoesntExist(); 
              };
          Handler: index.handler
          Runtime: nodejs4.3
          Role: 
           Fn::GetAtt: 
           - "LoggingRole"
           - "Arn"
    LoggingLambda:
        Type: AWS::Lambda::Function
        Properties: 
          Code:
            ZipFile: >
              var zlib = require('zlib');
              exports.handler = function(event, context, callback) {
                var payload = new Buffer(event.awslogs.data, 'base64');
                zlib.gunzip(payload, function(err, res) {
                  var parsed = JSON.parse(res.toString('utf8'));
                  var logGroup = parsed.logGroup;
                  var logStream = parsed.logStream;
                  var time = new Date(parsed.logEvents[0].timestamp).toISOString();
                  var loggingLink = "<https://console.aws.amazon.com/cloudwatch/home?region=us-west-2#logEventViewer:group=LOG_GROUP;stream=LOG_STREAM;start=START|Logging>";
                  loggingLink = loggingLink.replace("LOG_GROUP", logGroup);
                  loggingLink = loggingLink.replace("LOG_STREAM", logStream);
                  loggingLink = loggingLink.replace("START", time);
                  var msg = "ERROR! In logGroup" + logGroup + ": " + loggingLink;
                  console.log(msg);
                  //sendToSlack(msg); //Pretend you have a method to send to your slack instance
                  callback(null, msg);
                });  
              };
          Environment:
            Variables:
              Test : Test
          Handler: index.handler
          Runtime: nodejs4.3
          Role: 
           Fn::GetAtt: 
           - "LoggingRole"
           - "Arn"
    CrashingLogGroup:
        Type: "AWS::Logs::LogGroup"
        Properties: 
          LogGroupName:
                    Fn::Join:
                        - ''
                        - - /aws/lambda/
                          - !Ref CrashingLambda
    LoggingSubscription:
        Type: "AWS::Logs::SubscriptionFilter"
        Properties: 
          DestinationArn: 
                    Fn::GetAtt: 
                        - "LoggingLambda"
                        - "Arn"
          FilterPattern: "Process exited before completing request"
          LogGroupName: !Ref CrashingLogGroup
        DependsOn: LambdaInvokePermission  
                          
    LambdaInvokePermission: 
      Type: "AWS::Lambda::Permission"
      Properties: 
        FunctionName: !Ref LoggingLambda
        Action: "lambda:InvokeFunction"
        Principal: "logs.us-west-2.amazonaws.com"
        SourceAccount: 
          Ref: "AWS::AccountId"
    LoggingRole:
        Type: "AWS::IAM::Role"
        Properties: 
          AssumeRolePolicyDocument:
            Version: "2012-10-17"
            Statement: 
              - 
                Effect: "Allow"
                Principal: 
                  Service: 
                    - "lambda.amazonaws.com"
                Action: 
                  - "sts:AssumeRole" 
          ManagedPolicyArns:
           - arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole