StepFunction, DynamoDB: Query condition missed key schema element

Question

I'm trying to query a DynamoDB table in a Step Function but it's throwing the following error.

Query condition missed key schema element: Scope (Service: DynamoDb, Status Code: 400, Request ID: FN4G...)

The Step Function Task definition is;

    "Obtain Users info": {
      "Type": "Task",
      "Parameters": {
        "TableName": "Users",
        "KeyConditionExpression": "#Scope = :Global",
        "ExpressionAttributeNames": {
          "#Scope": {
            "S": "Scope"
          }
        },
        "ExpressionAttributeValues": {
          ":Global": {
            "S": "Global"
          }
        }
      },
      "Resource": "arn:aws:states:::aws-sdk:dynamodb:query",
      "Next": "Pass"
    },

The DyanmoDB definition is;

And here's a sample item from the table

{
  "Scope": {
    "S": "Global"
  },
  "ServiceName": {
    "S": "driver"
  },
  "lastVisitDateTime": {
    "N": "1680022106"
  },
  "Status": {
    "S": "ONLINE"
  }
}

Any pointers on what I'm missing?? Thanks!

Answer 1

Your parameters should be as follows:

    "Obtain Users info": {
      "Type": "Task",
      "Parameters": {
        "TableName": "Users",
        "KeyConditionExpression": "#Scope = :Global",
        "ExpressionAttributeNames": {
          "#Scope": "Scope"
        },
        "ExpressionAttributeValues": {
          ":Global": {
            "S": "Global"
          }
        }
      },
      "Resource": "arn:aws:states:::aws-sdk:dynamodb:query",
      "Next": "Pass"
    },

ExpressionAttributeNames does not take a data type as they are always defined as strings.