String values passed to Lambda-backed Custom Resource become E-notation

Question

**Issue:**  
  
Certain values that passed to Lambda-backed Custom Resource become exponential notation form.  
(even if I double-quoted the values)  
Values should be passed to lambda function as-is.

**CloudFormation Template to reproduce(non-important resources are omitted):**

```
  CfnCustomResourceFunction:
    Type: AWS::Lambda::Function
    Properties:
      FunctionName: cfn-custom-resource-function
      Handler:      index.handler
      Timeout:      900
      MemorySize:   128
      Runtime:      nodejs8.10
      Role:         !Sub ${CfnCustomResourceFunctionRole.Arn}
      Code:
        ZipFile: |
          var response = require('cfn-response');
          exports.handler = function(event, context) {
            console.log(JSON.stringify(event, null, 2));
            response.send(event, context, response.SUCCESS, {});
          };

  CustomResource:
    Type: Custom::CfnCustomResourceFunction
    Properties:
      ServiceToken: !Sub ${CfnCustomResourceFunction.Arn}
      Value1: "011111111111"
      Value2: "022222222222"
      Value3: "033333333333"
      Value4: "044444444444"
      Value5: "055555555555"
      Value6: "066666666666"
      Value7: "077777777777"
      Value8: "088888888888"
      Value9: "099999999999"
```

**CloudWatch Logs(some values are sanitized):**

```
2019-03-01T05:32:20.091Z	e3e35acf-96ce-4290-8315-1f0520fcd772
{
    "RequestType": "Create",
    "ServiceToken": "arn:aws:lambda:ap-northeast-1:xxxxxxxxxxxx:function:cfn-custom-resource-function",
    "ResponseURL": "https://cloudformation-custom-resource-response-apnortheast1.s3-ap-northeast-1.amazonaws.com/arn%3Aaws%3Acloudformation%3Aap-northeast-1%3Axxxxxxxxxxxx%3Astack/stack-name/18d8c640-0801-11e9-b562-0e819627e6da%7CCustomResource%7C59875204-de7e-4cd3-83db-83f260fea2d7?AWSAccessKeyId=AKIAI263AXSLMBRIXBRA&Expires=1551425539&Signature=L2fsXHLeMFeIlbQ5%2FUlhCLFgt0A%3D",
    "StackId": "arn:aws:cloudformation:ap-northeast-1:xxxxxxxxxxxx:stack/stack-name/18d8c640-0801-11e9-b562-0e819627e6da",
    "RequestId": "59875204-de7e-4cd3-83db-83f260fea2d7",
    "LogicalResourceId": "CustomResource",
    "ResourceType": "Custom::CfnCustomResourceFunction",
    "ResourceProperties": {
        "ServiceToken": "arn:aws:lambda:ap-northeast-1:xxxxxxxxxxxx:function:cfn-custom-resource-function",
        "Value9": "9.9999999999E10",
        "Value3": "033333333333",
        "Value4": "044444444444",
        "Value1": "011111111111",
        "Value2": "022222222222",
        "Value7": "077777777777",
        "Value8": "8.8888888888E10",
        "Value5": "055555555555",
        "Value6": "066666666666"
    }
}
```

Take a look at "Value8" and "Value9"  
  
**Background:**  
  
I noticed when I had been creating lambda function that takes list of AWS account numbers, and some of my AWS account numbers are actually hitting this issue.  
  
**Request/Question:**  
  
Is this a bug of Lambda Backed CFn Custom Resource?  
Is there any workaround for this issue?

Answer

I identified the root cause of the issue and it was not the problem of CloudFormation.  
It seems it is bug at `aws cloudformation package` command during the build pipeline.

```
Parameters:
  Value7:
    Type: String
    Default: "077777777777"
  Value8:
    Type: String
    Default: "088888888888"
  Value9:
    Type: String
    Default: "099999999999"
Resources:
  NestedStack:
    Type: AWS::CloudFormation::Stack
    Properties:
      TemplateURL: ./template_child.yml
```

```
$ aws --version
aws-cli/1.16.110 Python/3.7.2 Darwin/18.2.0 botocore/1.12.100

$ aws cloudformation package --s3-bucket BUCKET_NAME --template-file template.yml                                                           
Uploading to 137ce8b72427772da39a43ddc087908a.template  101 / 101.0  (100.00%)
Parameters:
  Value7:
    Type: String
    Default: '077777777777'
  Value8:
    Type: String
    Default: 088888888888
  Value9:
    Type: String
    Default: 099999999999
Resources:
  NestedStack:
    Type: AWS::CloudFormation::Stack
    Properties:
      TemplateURL: https://s3.amazonaws.com/BUCKET_NAME/137ce8b72427772da39a43ddc087908a.template
```

Quotes are removed after `aws cloudformation package` and treated as number value.  
  
I'll report this issue to aws-cli Github repository and mark this issue as "Answered".

String values passed to Lambda-backed Custom Resource become E-notation

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