Adding tags in CFT

Question

I am trying to add tags by passing all the tags in key value pair from the parameters. But I am not able to do so because of this error.

`Properties validation failed for resource bucket with message: #/Tags: expected type: JSONArray, found: String
`

Here is my template:
{
  "AWSTemplateFormatVersion": "2010-09-09",
  "Description": "The template for S3 bucket",
  "Parameters": {
    "s3BucketName": {
      "Type": "String",
      "Default": "test-bucket"
    },
    "projectName": {
      "Type": "String",
      "Default": "test"
    },
    "tag": {
      "Type": "String",
      "Default": "[{\"Key\":\"project\",\"Value\":\"test\"},{\"Key\":\"owner\",\"Value\":\"test\"}]"
    }
    
  },
  "Resources": {
    "bucket": {
      "Type": "AWS::S3::Bucket",
      "Properties": {
        "BucketName": {"Ref": "s3BucketName"},
        "PublicAccessBlockConfiguration": {
          "BlockPublicAcls": false,
          "BlockPublicPolicy": false,
          "IgnorePublicAcls": false,
          "RestrictPublicBuckets": false
        },
        "Tags": {"Fn::Sub": "${tag}"}

}
    }
  },
  "Outputs": {
    "arn": {
      "Description": "The Arn of the S3 bucket.",
      "Value": {"Fn::GetAtt": ["bucket", "Arn"]}
    }
  }
}

Answer

CloudFormation supports adding resource tags directly to the resources that support tagging, for example;

```
    "Resources": {
        "bucket": {
            "Type": "AWS::S3::Bucket",
            "Properties": {
                "BucketName": {
                    "Ref": "s3BucketName"
                },
                "PublicAccessBlockConfiguration": {
                    "BlockPublicAcls": false,
                    "BlockPublicPolicy": false,
                    "IgnorePublicAcls": false,
                    "RestrictPublicBuckets": false
                },
                "Tags": [
                    {
                        "Key": "keyname1",
                        "Value": "value1"
                    },
                    {
                        "Key": "keyname2",
                        "Value": "value2"
                    }
                ]
            }
        }
    },
```

CloudFormation does not support adding Tags as a **Parameter** value within the stack. The following is the list of supported [Types](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/parameters-section-structure.html#parameters-section-structure-properties-type). Tags are required to be a List hence the error message returned requesting a JSONArray rather a String. However, CloudFormation currently only supports a List type.

Adding tags in CFT

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