cloudformation-helpers/lookup_stack_outputs.template

{
  "AWSTemplateFormatVersion": "2010-09-09",
  "Resources": {
    "LookupStackOutputsRole": {
      "Type": "AWS::IAM::Role",
      "Properties": {
        "AssumeRolePolicyDocument": {
          "Version" : "2012-10-17",
          "Statement": [
            {
              "Effect": "Allow",
              "Principal": {
                "Service": [ "lambda.amazonaws.com" ]
              },
              "Action": [ "sts:AssumeRole" ]
            }
          ]
        },
        "Policies": [
          {
            "PolicyName": "LogWriter",
            "PolicyDocument": {
              "Version" : "2012-10-17",
              "Statement": [
                {
                  "Effect": "Allow",
                  "Action": [
                    "logs:CreateLogGroup",
                    "logs:CreateLogStream",
                    "logs:PutLogEvents"
                  ],
                  "Resource": "arn:aws:logs:*:*:*"
                }
              ]
            }
          },
          {
            "PolicyName": "CFReader",
            "PolicyDocument": {
              "Version" : "2012-10-17",
              "Statement": [
                {
                  "Effect": "Allow",
                  "Action": [
                    "cloudformation:DescribeStacks"
                  ],
                  "Resource": "*"
                }
              ]
            }
          }
        ]
      }
    },
    "LookupStackOutputs": {
      "Type": "AWS::Lambda::Function",
      "Properties": {
        "Handler": "index.handler",
        "Role": { "Fn::GetAtt": [ "LookupStackOutputsRole", "Arn" ] },
        "Code": {
          "ZipFile": {
            "Fn::Join": [
              "",
              [
                "var response = require('cfn-response');",
                "exports.handler = function(event, context) {",
                  "console.log('REQUEST RECEIVED:\\n', JSON.stringify(event));",
                  "if (event.RequestType == 'Delete') {",
                    "response.send(event, context, response.SUCCESS);",
                    "return;",
                  "}",
                  "var stackName = event.ResourceProperties.StackName;",
                  "var responseData = {};",
                  "if (stackName) {",
                    "var aws = require('aws-sdk');",
                    "var cfn = new aws.CloudFormation();",
                    "cfn.describeStacks({StackName: stackName}, function(err, data) {",
                      "if (err) {",
                        "responseData = {Error: 'DescribeStacks call failed'};",
                        "console.log(responseData.Error + ':\\n', err);",
                        "response.send(event, context, response.FAILED, responseData);",
                      "} else {",
                        "data.Stacks[0].Outputs.forEach(function(output) {",
                          "responseData[output.OutputKey] = output.OutputValue;",
                        "});",
                        "response.send(event, context, response.SUCCESS, responseData);",
                      "}",
                    "});",
                  "} else {",
                    "responseData = {Error: 'Stack name not specified'};",
                    "console.log(responseData.Error);",
                    "response.send(event, context, response.FAILED, responseData);",
                  "}",
                "};"
              ]
            ]
          }
        },
        "Runtime": "nodejs4.3",
        "Timeout": "30"
      },
      "DependsOn": [
        "LookupStackOutputsRole"
      ]
    }
  },
  "Outputs": {
    "LookupStackOutputsArn": {
      "Description": "The ARN of the LookupStackOutputs function, for use in other CloudFormation templates.",
      "Value": { "Fn::GetAtt" : ["LookupStackOutputs", "Arn"] }
    }
  }
}