$util.qr($context.args.input.put("createdAt", $util.defaultIfNull($ctx.args.input.createdAt, $util.time.nowISO8601() )))
$util.qr($context.args.input.put("value", $util.defaultIfNull($ctx.args.input.value, 0)))
{
  "version": "2017-02-28",
  "operation": "PutItem",
  "key": {
    "name": $util.dynamodb.toDynamoDBJson($ctx.args.input.name),
    "createdAt": $util.dynamodb.toDynamoDBJson($ctx.args.input.createdAt),
  },
  "attributeValues": $util.dynamodb.toMapValuesJson($ctx.args.input),
  "condition": {
    "expression": "attribute_not_exists(#name) AND attribute_not_exists(#createdAt)",
    "expressionNames": {
      "#name": "name",
      "#createdAt": "createdAt",
    },
  },
}