Amazon web services 执行PutItem时发生ValidationException:项中缺少键：ClientError

我在Python2.7中配置了一个AWS Lambda，从Firehose交付流读取事件，并将属性“element_class”（type String）作为分区键写入DynamoDB表“My_Tab”

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")

为了流式传输到消防软管，我对JSON文件my_data.JSON进行二进制编码，然后使用AWS CLI put record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..."
}

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

JSON文件my_data.JSON有一个JSON记录，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..."
}

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

但是数据没有写入DynamoDB表My_选项卡，并带有以下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

---

只是添加了下面的代码来从事件的recordId of records属性中提取数据，而不是直接获取事件。它成功了

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

---

@blueCat：感谢您指向打印事件。我期望的数据格式是错误的

在函数开头添加一个

print（json.dumps（event））

。您的事件是否有一个顶级键

元素类

？是的，我的事件有一个名为“元素类”的顶级键。它将有一个字符串值。您可以从日志中添加

print（json.dumps（event））

的输出吗？