Add label to dimensions

[rflume]

Hi,
as CloudWatch supports labeling an instance in the widget (e.g. 'Production' rather than the instance ID) I thought it would be awesome to be able to add a label to the dimensions list of the module as well.

The JSON with an instance/metric label looks as follows:

{
    "widgets": [
        {
            "type": "metric",
            ...
            "properties": {
                "metrics": [
                    [
                        "System/Linux",
                        "MemoryUtilization",
                        "InstanceId",
                        "i-098b4673130e90378",
                        {
                            "label": "Production"
                        }
                    ]
                ],
                "view": "timeSeries",
                ...
            }
        }
    ]
}

I thought about adding the label object as follows:

dimensions = [
    "InstanceId, i-12345, {\"label\": \"test1\"}",
    "InstanceId, i-67890, {\"label\": \"test2\"}"
]  

This would generate the template correctly in the output:

cpu_utilization_metrics = [["AWS/EC2","CPUUtilization","InstanceId","i-04e11cef7ecb23847","{\"label\": \"test1\"}"], ["AWS/EC2","CPUUtilization","InstanceId","i-0131fab3c1a26f959","{\"label\": \"test2\"}"]]

But applying the template to a dashboard resource I get the following error:

Error: Error running plan: 1 error occurred:
	* aws_cloudwatch_dashboard.dashboard: "dashboard_body" contains an invalid JSON: invalid character '/' looking for beginning of value

Do you think there's another way of achieving this?
Maybe by passing a listofmaps as a seperate variable to the module and combine the dimensions with a map somehow?