编写Boto3过滤器以使用自定义标签名称的正确方法是什么？ [英] What is the correct ways to write Boto3 filters to use customise tag name?

问题描述

我试图在不同标签键
的标签值上列出实例，例如>一个标签键-环境，其他标签键-角色。
我的代码如下：

I am trying to list the instances on tag values of different tag keys For eg> one tag key - Environment, other tag key - Role. My code is given below :

import argparse
import boto3

AWS_ACCESS_KEY_ID = '<Access Key>'
AWS_SECRET_ACCESS_KEY = '<Secret Key>'

def get_ec2_instances(Env,Role):
    ec2 = boto3.client("ec2", region)
    reservations = ec2.describe_instances(Filters={"tag:environment" :   Env, "tag:role" : Role})
    for reservation in reservations["Reservations"] :
        for instance in reservation["Instances"]:
             print  "%s" % (instance.tags['Name'])

if  __name__ == '__main__':

    regions = ['us-east-1','us-west-1','us-west-2','eu-west-1','sa-east-1',
               'ap-southeast-1','ap-southeast-2','ap-northeast-1']
    parser = argparse.ArgumentParser()
    parser.add_argument('Env', default="environment", help='value for   tag:environment');
    parser.add_argument('Role', default="role", help='value for tag:role');
    args = parser.parse_args()

    for region in regions: get_ec2_instances(args.Env, args.Role)

运行此脚本后：python script.py arg1 arg2

After running this script : python script.py arg1 arg2

我遇到以下错误

Traceback (most recent call last):
  File "script.py", line 27, in <module>
    for region in regions: get_ec2_instances(args.Env, args.Role)
  File "script.py", line 10, in get_ec2_instances
    reservations = ec2.describe_instances(Filters={"tag:environment" :  Env, "tag:role" : Role})
  File "/usr/local/lib/python2.7/dist-packages/botocore/client.py", line 258, in _api_call
    return self._make_api_call(operation_name, kwargs)
  File "/usr/local/lib/python2.7/dist-packages/botocore/client.py", line 524, in _make_api_call
    api_params, operation_model, context=request_context)
  File "/usr/local/lib/python2.7/dist-packages/botocore/client.py", line 577, in _convert_to_request_dict
    api_params, operation_model)
  File "/usr/local/lib/python2.7/dist-packages/botocore/validate.py", line 270, in serialize_to_request
    raise ParamValidationError(report=report.generate_report())
botocore.exceptions.ParamValidationError: Parameter validation failed:
Invalid type for parameter Filters, value: {'tag:role': 'arg1', 'tag:environment': 'arg2'}, type: <type 'dict'>, valid types: <type 'list'>, <type 'tuple'>

推荐答案

这看起来很熟悉，我是否为某个地方的人修改过;-)。实际上，我编写的代码很匆忙，并且没有经过正确的测试（而且我不会费心修改％字符串格式并将其替换为str.format（））。实际上，在AWS中没有正确记录使用Filters参数。

This looks familiar, did I modify this for somebody somewhere ;-) . Actually the code I wrote is in rush and not tested properly (And I don't bother to amend the % string formating and replace it with str.format() ) . In fact,using Filters parameter is not properly documented in AWS.

请参阅Russell Ballestrini博客使用Boto3过滤AWS资源，以了解有关正确的Boto过滤器方法的更多信息。

Please refer to Russell Ballestrini blog Filtering AWS resources with Boto3 to learn more about correct boto Filters method.

1. 过滤器接受列表值，标记内的信息应为dict。因此[{}]


2. Boto3文档在如何使用指定标记名称方面非常含糊。没有示例，当他们说您可以使用tag：key时，这很令人困惑。这么多人只会做 [{ tag：keyname， Values ::]}] ，但它不起作用。 （实际上，我认为开发人员知道过滤器是如何工作的原始代码，因此我只修改了结构）。


3. 实际上，您必须明确指定名称和值对。因此，指定标签名称的正确方法是 [{ Name： tag：keyname， Values：[]}] 。

1. Filters accept list value, and info inside the tag should be dict. thus [{}]
2. Boto3 documentation is pretty ambiguous on how to use specify the tag name. It is confusing without examples when they say you may use tag:key. So many people will just do [{"tag:keyname","Values": [""] }] and it doesn't work. (Actually the origin code I assume the developer know how the filters works, so I just amend the structure only).
3. Actually, You MUST explicitly specify "Name" and "Values" pair. So the correct way to specify tag name is [{"Name" :"tag:keyname", "Values":[""] }]. It is tricky.

因此，如果要在示例中使用

So the correct way of formatting a filters if you want to use for your example

filters = [{'Name':'tag:environment', 'Values':[Env]},
           {'Name':'tag:role', 'Values':[Role]}
          ]

（更新）
为了确保argparse占用字符串值，您只需执行参数即可采用字符串值

(Update) And to make sure argparse take up string value, you just enforce the argument to take string values

parser.add_argument('Env', type=str, default="environment",
                    help='value for   tag:environment');
parser.add_argument('Role', type=str,default="role",
                    help='value for tag:role');

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