执行PutItem时发生ValidationException:项中缺少键：ClientError

Question

我在Python 2.7中配置了一个AWS Lambda，用于从Firehose交付流中读取事件，并写入DynamoDB表“My_Tab”，其中属性“element_class”(类型字符串)作为分区键

import json
import boto3

def lambda_data_handler(event, context):

    dynamodb = boto3.resource('dynamodb', region_name='ap-south-1')
    table = dynamodb.Table('My_Tab')

    response = table.put_item(Item = event)
    print(json.dumps(response))
    print("Row-" + str(index) + " written to DynamoDB successfully")

对于流式传输到Firehose，我是对JSON文件进行二进制编码my_data.json然后使用AWS CLI put-记录实用程序发送数据，如下所示：

c:\Program Files\Amazon\AWSCLI>aws firehose put-record --delivery-stream-name My_Dlv_Stream --record file://C:/Users/somnath/my_data.json
{
    "RecordId": "DvH2dm5W75F9+bwjJesUW8FoPqQZJOF66etwGoWUycMX..."
}

json文件my_data.json有一个JSON记录，如下所示:

{"Data":"{\"element_class\":\"1001\"}\n"}

但是数据没有被写入DynamoDB表My_Tab，下面是CloudWatch错误日志:

An error occurred (ValidationException) when calling the PutItem operation: One or more parameter values were invalid: Missing the key element_class in the item: ClientError
Traceback (most recent call last):
File "/var/task/lambda_KFH_2_DynDB.py", line 21, in lambda_data_handler
response = table.put_item(Item = event)
File "/var/task/boto3/resources/factory.py", line 520, in do_action
response = action(self, *args, **kwargs)
File "/var/task/boto3/resources/action.py", line 83, in __call__
response = getattr(parent.meta.client, operation_name)(**params)
File "/var/task/botocore/client.py", line 314, in _api_call
return self._make_api_call(operation_name, kwargs)
File "/var/task/botocore/client.py", line 612, in _make_api_call
raise error_class(parsed_response, operation_name)
ClientError: An error occurred (ValidationException) when calling the PutItem operation: One or more parameter values were invalid: Missing the key element_class in the item

Answer 1

只是添加了下面的代码来从事件的记录属性的记录ID中提取数据，而不是直接获取事件。它奏效了。

    it = json.loads(event['records'][0]['data'])
    response = table.put_item(Item = it)

@blueCat:感谢指向打印事件。我期望的数据格式是错误的。