使用for循环时畸形InstanceID的AWS InstanceID误差

Question

嗨，当使用for循环输入实例id时，我遇到了一个错误。下面是我的代码和错误。

代码只是将所有实例is放在一个文件中，我在for循环中使用该文件来获得一个描述实例输出。

格式似乎很好，当我手动输入实例id时，它工作得很好。让我知道

#!/usr/bin/python3
import boto3
import csv

ec2_re = boto3.resource('ec2')
ids= [instance.id for instance in ec2_re.instances.all()]
with open('ids.txt', 'w') as file_handler:
    for id in ids:
        file_handler.write("'{}'\n".format(id))

ec2 = boto3.client('ec2', region_name='us-east-1')
INSTANCE_ID = open("ids.txt", "r")  #need to loop thru this
for x in INSTANCE_ID:
    result = []
    response = ec2.describe_instances(
        InstanceIds=[
            x
        ]).get('Reservations')

错误

Traceback (most recent call last):
  File "./excel_new.py", line 17, in <module>
    x
  File "/usr/local/lib/python3.7/site-packages/botocore/client.py", line 514, in _api_call
    return self._make_api_call(operation_name, kwargs)
  File "/usr/local/lib/python3.7/site-packages/botocore/client.py", line 934, in _make_api_call
    raise error_class(parsed_response, operation_name)
botocore.exceptions.ClientError: An error occurred (InvalidInstanceID.Malformed) when calling the DescribeInstances operation: Invalid id: "'i-03b6908c79e0dd9dd'

Answer 1

在没有多余引号的情况下编写实例ID。例如：

file_handler.write("{}\n".format(id))

在以后如何读取文本文件中有一个次要问题。您需要从包含实例ID的文本行中删除换行符。例如：

with open("ids.txt", "r") as fp:
    for id in [line.rstrip() for line in fp.readlines()]:
        print(id)

下面是一个更完整的示例，它既写入又读取实例ID：

ids = ["id-12345", "id-23456", "id-34567"]

with open("ids.txt", "w") as fp:
    for id in ids:
        fp.write(f"{id}\n")

with open("ids.txt", "r") as fp:
    for id in [line.rstrip() for line in fp.readlines()]:
        print(id)

因为Python中的文件对象是迭代器，所以还可以使用：

for id in [line.rstrip() for line in open("ids.txt", "r")]:
    print(id)