Boto3 缺少联系人标签值，没有错误

Question

我有这部分脚本应该返回一个联系人值，但脚本正在运行并且没有打印任何联系人值。 我试图将第二个 try 语句向后移动一个缩进，但结果仍然相同。 它应该打印出“instance_contacttag”作为联系人值。 我确定这很简单，但我似乎无法理解，谢谢。

for reservation in reservations:
        # tags = {}
        for instance in reservation['Instances']:
            tags = {}
            instance_ids = instance['InstanceId']
            print(instance_ids + " is the instance id within the instance_ids dictionary")
            try:
                for tag in instance['Tags']:
                    tags[tag['Key']] = tag['Value']
                    # print(instance['Tags'])

                    if tag['Key'] == 'Name':
                        # print(tag['Value'])
                        instance_nametag = tag['Value']
            except:
                pass
                
                try: 
                    if tag['Key'] == 'contact':
                        instance_contacttag = tag['Value']
                        print(instance_contacttag)
                                         
                except:
                    print("CONTACT TAG MISSING")

Answer 1

标签的枚举不会产生异常，这意味着如果该项目不在列表中，您将看不到该项目。

将标签列表转换为字典要容易得多，并执行简单的字典查找以查看是否存在项目：

import boto3
ec2 = boto3.client('ec2')
data = ec2.describe_instances()
reservations = data['Reservations']

for reservation in reservations:
    for instance in reservation['Instances']:
        tags = instance['Tags']
        # Convert the tag list to a Python dictionary to make looking up tags easier
        tags = {x['Key']: x['Value'] for x in tags}

        # Show the Instance ID
        instance_ids = instance['InstanceId']
        print(instance_ids + " is the instance id within the instance_ids dictionary")

        if 'Name' in tags:
            instance_nametag = tags['Name']
            print("Name: " + instance_nametag)

        # Look for the 'contact' tag
        if 'contact' in tags:
            instance_contacttag = tags['contact']
            print("Contact: " + instance_contacttag)
        else:
            # It's not present, show a warning
            print("CONTACT TAG MISSING")