AWS DynamoDB数据转换为Python/Boto3/Lamba中的json格式

Question

我有一个DynamoDB表，它需要转换为json格式，并使用Python/Boto3/AWS Lambda环境在API响应中共享

userMetrics[
{
  "userid": 1234567890,  ==> key
  "likemetrics": 0,
  "lasttimestamp": 1604553995
},
{
  "userid": 1234567891,  ==> key
  "likemetrics": 0,
  "lasttimestamp": 1604553998
}]

我试图使用Formatting DynamoDB data to normal JSON in AWS Lambda中提到的示例将整个DynamoDB表复制为json格式 但在执行过程中也会面临错误

{
"errorMessage": "'dynamodb.Table' object has no attribute 'items'",
"errorType": "AttributeError",
"stackTrace":[
"  File \"/var/task/lambda_function.py\", line 75, in lambda_handler\n    'usermetrics': json.dumps(from_dynamodb_to_json(dydb_userTable))\n",
"  File \"/var/task/lambda_function.py\", line 7, in from_dynamodb_to_json\n    return {k: d.deserialize(value=v) for k, v in item.items()}\n"
]
}

我的lambda代码实现：

import json
import boto3
from boto3.dynamodb.types import TypeDeserializer, TypeSerializer

def from_dynamodb_to_json(item):
    d = TypeDeserializer()
    return {k: d.deserialize(value=v) for k, v in item.items()}

dydb = boto3.resource('dynamodb')
dydb_userTable = dydb.Table('userMetrics')

def lambda_handler(event, context):
        return {
            'statusCode': 200,
            'usermetrics': json.dumps(from_dynamodb_to_json(dydb_userTable))
        }

Answer 1

Table（dydb_userTable在代码中）对象没有您要查找的items。您需要在该表上调用一个方法，该方法将为您检索项，例如dydb_userTable.scan()或dydb_userTable.query()

参考：https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/dynamodb.html#table