" KeyError:“记录""在AWS S3中-Lambda触发器 [英] "KeyError: 'Records'" in AWS S3 - Lambda trigger

问题描述

我有以下lambda函数代码，用于简单地打印出S3存储桶中已上传事件的作者和元数据:

I have the following lambda function code for simply printing out the Author and metadata of an uploaded event of an S3 bucket:

from __future__ import print_function
import json
import urllib
import boto3

print('Loading function')

s3 = boto3.client('s3')


def lambda_handler(event, context):

    #print("Received event: " + json.dumps(event, indent=2))
    # bucket = event['Records'][0]['s3']['bucket']['name']

    for record in event['Records']:
        bucket = record[0]['s3']['bucket']['name']
        key = record[0]['s3']['object']['key']
        response = s3.head_object(Bucket=bucket, Key=key)

        logger.info('Response: {}'.format(response))

        print("Author : " + response['Metadata']['author'])
        print("Description : " + response['Metadata']['description'])

但是，我在测试时遇到以下错误:

However, I am getting the following error while testing:

{
  "stackTrace": [
    [
      "/var/task/lambda_function.py",
      17,
      "lambda_handler",
      "for record in event['Records']:"
    ]
  ],
  "errorType": "KeyError",
  "errorMessage": "'Records'"
}

访问S3对象的存储桶名称和键名时，我做错什么了吗?如果没有，那我在做什么错了?

Am I doing anything wrong while accessing the bucket name and key name of the S3 object? If not, then what am I doing wrong here?

推荐答案

晚了一点.但是，这是我的第一篇文章！

bit late to the party. But here is my first post!

EXPLANATION:

当您在lambda面板中进行测试时-> def lambda_handler(event，context)<-事件将直接注入.

When you test in lambda panel -> def lambda_handler(event, context) <- event is injected directly.

但是在AWS API中，必须添加映射模板或否则->事件<-为空，从而导致测验:

However in AWS API its neccessary to add Mapping Template or otherwise -> event <- is empty, thus resulting in quizzing:

"errorType":"KeyError"，"errorMessage":'Records'"

"errorType": "KeyError", "errorMessage": "'Records'"

这是空指针.记录不存在，因为->事件<-不存在.

this is null pointer. Records doesnt exist, since -> event <- doesnt exist.

解决方案:

您需要在AWS API中配置集成请求. 点击身体映射模板. 然后添加映射模板 将内容类型设置为 application/json 然后编辑生成的映射模板:

You need to configure Integration Request inside AWS API. Click on Body Mapping Templates. Then add Mapping Template Set content type to application/json Then edit generated mapping template:

{
  "body" : $input.json('$'),
  "headers": {
    #foreach($header in $input.params().header.keySet())
    "$header": "$util.escapeJavaScript($input.params().header.get($header))" #if($foreach.hasNext),#end

    #end
  },
  "method": "$context.httpMethod",
  "params": {
    #foreach($param in $input.params().path.keySet())
    "$param": "$util.escapeJavaScript($input.params().path.get($param))" #if($foreach.hasNext),#end

    #end
  },
  "query": {
    #foreach($queryParam in $input.params().querystring.keySet())
    "$queryParam": "$util.escapeJavaScript($input.params().querystring.get($queryParam))" #if($foreach.hasNext),#end

    #end
  }  
}

和编辑Lambda函数:

替换:

用于事件['Records']中的记录:

for record in event['Records']:

具有:

用于事件['query'] ['Records']

for record in event['query']['Records']

不知道堆栈是否可以ping通您这个答案-所以我称呼您@ Dawny33 @KevinOelen @franklinsijo

don't know whether stack will ping you with this answer - so i call you @Dawny33 @KevinOelen @franklinsijo

至于解释，我自己想了一下.但是，映射模板"来自 https://medium.com/simple-thoughts-amplified/passing-variables-from-aws-api-gateway-to-lambda-3c5d8602081b

As for explanation i figured it on my own. However "mapping template" comes from https://medium.com/simple-thoughts-amplified/passing-variables-from-aws-api-gateway-to-lambda-3c5d8602081b

这篇关于&quot; KeyError:“记录""在AWS S3中-Lambda触发器的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！