AWS Lambda DynamoDB查询错误

Question

I am programming an AWS Lambda function in python. I am using boto3 to connect to the DynamoDB database and I am trying to retrieve the last location entry.

The DynamoDB table is has a primary partition key of "Serial" which is a string, and a primary sort key of "Time", also a string.

When I run this code, trying to get the last entry for serial "0001" I get the following error

def getPriorGeofence(device):
client = boto3.client('dynamodb')
response = client.query(
    TableName='Locations',
    IndexName='Serial',
    Select='ALL_ATTRIBUTES',
    Limit=1,
    ScanIndexForward=True,
    KeyConditions={
        "Serial":{
            'ComparisonOperator': "EQ",
            'AttributeValueList': [device]
        }
    }
    )
return response

Error

{
  "stackTrace": [
    [
      "/var/task/lambda_function.py",
      154,
      "lambda_handler",
      "priorGeofence = getPriorGeofence(serial)"
    ],
    [
      "/var/task/lambda_function.py",
      110,
      "getPriorGeofence",
      "'AttributeValueList': [device]"
    ],
    [
      "/var/runtime/botocore/client.py",
      253,
      "_api_call",
      "return self._make_api_call(operation_name, kwargs)"
    ],
    [
      "/var/runtime/botocore/client.py",
      517,
      "_make_api_call",
      "api_params, operation_model, context=request_context)"
    ],
    [
      "/var/runtime/botocore/client.py",
      572,
      "_convert_to_request_dict",
      "api_params, operation_model)"
    ],
    [
      "/var/runtime/botocore/validate.py",
      270,
      "serialize_to_request",
      "raise ParamValidationError(report=report.generate_report())"
    ]
  ],
  "errorType": "ParamValidationError",
  "errorMessage": "Parameter validation failed:\nInvalid type for parameter KeyConditions.Serial.AttributeValueList[0], value: 0001, type: <type 'unicode'>, valid types: <type 'dict'>"
}

Answer 1

Change the AttributeValueList value as mentioned below (ie mentioning the data type as String 'S' explicitly):-

 KeyConditions={
        "Serial":{
            'ComparisonOperator': "EQ",
            'AttributeValueList': [{'S' : device}]
        }
    }