Question

我希望从我的Lambda函数中获取EC2InstanceId，但不知何故我遇到了一个错误string indices must be integers: TypeError 这是代码：

from __future__ import print_function
import json
import re
import boto3

def lambda_handler(event, context):
    """
    lambda handler function.
    """
    message = event['Records'][0]['Sns']['Message']
    print(message)
    ec2InstanceId = event['Records'][0]['Sns']['Message']['EC2InstanceId']
    print(ec2InstanceId)

但是，我从print(message)得到以下输出：

{
    "Progress": 50,
    "AccountId": "*****************",
    "Description": "Launching a new EC2 instance: i-0316df8d5159ee6a7",
    "RequestId": "4b15abf1-7b48-4e9b-528a-891992eabc86",
    "EndTime": "2019-05-28T02:57:46.975Z",
    "AutoScalingGroupARN": "arn:aws:autoscaling:us-east-1:*****************:autoScalingGroup:*****************:autoScalingGroupName/dynamic-host-asg",
    "ActivityId": "*****************",
    "StartTime": "2019-05-28T02:57:13.747Z",
    "Service": "AWS Auto Scaling",
    "Time": "2019-05-28T02:57:46.975Z",
    "EC2InstanceId": "i-0316df8d5159ee6a7",
    "StatusCode": "InProgress",
    "StatusMessage": "",
    "Details": {
        "Subnet ID": "*****************",
        "Availability Zone": "us-east-1b"
    },
    "AutoScalingGroupName": "dynamic-host-asg",
    "Cause": "At 2019-05-28T02:56:47Z a user request update of AutoScalingGroup constraints to min: 1, max: 2, desired: 1 changing the desired capacity from 0 to 1.  At 2019-05-28T02:57:11Z an instance was started in response to a difference between desired and actual capacity, increasing the capacity from 0 to 1.",
    "Event": "autoscaling:EC2_INSTANCE_LAUNCH"
}

但是print(ec2InstanceId)给我以下错误：

string indices must be integers: TypeError
Traceback (most recent call last):
File "/var/task/lambda_function.py", line 27, in lambda_handler
ec2InstanceId = event['Records'][0]['Sns']['Message']['EC2InstanceId']
TypeError: string indices must be integers

您能帮我解决这个问题吗？

Answer 1

我让它像这样

    message = event['Records'][0]['Sns']['Message']
    if isinstance(message, str):
        try:
            message = json.loads(message)
        except Exception as e:
            print(e) 
    elif isinstance(message, list):
        message = message[0]
    asg_instances_list=message['EC2InstanceId']

有没有办法读取SNS传递的Lambda Function（Boto3）中的EC2InstanceId

1 个答案: