从 aws lambda 事件中检索存储桶名称时，我收到此错误。 （“errorMessage”：“'Records'”“errorType”：“KeyError”）

Question

我要运行的命令是

def lambda_handler(event, context):
    print(event)
    
    #retrieve bucket name and file_key from the S3 event
    bucket_name = event['Records'][0]['s3']['bucket']['name']
    file_key = event['query']['Records'][0]['s3']['object']['key']

结果：

{'key1': 'value1', 'key2': 'value2', 'key3': 'value3'}

错误：

[ERROR] KeyError: 'Records'
Traceback (most recent call last):
  File "/var/task/lambda_function.py", line 12, in lambda_handler
    bucket_name = event['Records'][0]['s3']['bucket']['name']
END RequestId: 29150087-77bd-49db-a88b-61eb8a1645fd

Answer 1

查看print 语句的输出，很明显该事件没有名为Records 的属性。

{
    'key1': 'value1', 
    'key2': 'value2', 
    'key3': 'value3'
}

所以当你运行event['Records'] 时它不起作用。因为上面的 JSON 没有名称为 Records 的属性。

如果您有以下 JSON，这将起作用：

{
    'Records': [],
    'key1': 'value1', 
    'key2': 'value2', 
    'key3': 'value3'
}

如果那是 JSON，那么 events['Records'] 将返回 []。

根据您的事件 JSON，我可以判断您正在使用 AWS 控制台“测试”功能默认事件 JSON。

您需要在 AWS 控制台中为 AWS S3 事件提供正确的 JSON。

在此处记录：Event message structure

JSON 应该如下所示：

{  
   "Records":[  
      {  
         "eventVersion":"2.2",
         "eventSource":"aws:s3",
         "awsRegion":"us-west-2",
         "eventTime":"The time, in ISO-8601 format, for example, 1970-01-01T00:00:00.000Z, when Amazon S3 finished processing the request",
         "eventName":"event-type",
         "userIdentity":{  
            "principalId":"Amazon-customer-ID-of-the-user-who-caused-the-event"
         },
         "requestParameters":{  
            "sourceIPAddress":"ip-address-where-request-came-from"
         },
         "responseElements":{  
            "x-amz-request-id":"Amazon S3 generated request ID",
            "x-amz-id-2":"Amazon S3 host that processed the request"
         },
         "s3":{  
            "s3SchemaVersion":"1.0",
            "configurationId":"ID found in the bucket notification configuration",
            "bucket":{  
               "name":"bucket-name",
               "ownerIdentity":{  
                  "principalId":"Amazon-customer-ID-of-the-bucket-owner"
               },
               "arn":"bucket-ARN"
            },
            "object":{  
               "key":"object-key",
               "size":"object-size",
               "eTag":"object eTag",
               "versionId":"object version if bucket is versioning-enabled, otherwise null",
               "sequencer": "a string representation of a hexadecimal value used to determine event sequence, only used with PUTs and DELETEs"
            }
         },
         "glacierEventData": {
            "restoreEventData": {
               "lifecycleRestorationExpiryTime": "The time, in ISO-8601 format, for example, 1970-01-01T00:00:00.000Z, of Restore Expiry",
               "lifecycleRestoreStorageClass": "Source storage class for restore"
            }
         }
      }
   ]
}