在对流层中向现有sns主题添加订阅

Question

我有一个用例，其中我有一个现有的sns主题，并且我正在使用cloudformation和对流层创建lambda函数。我必须以某种方式创建我的堆栈，在这种方式下，主题向我的lambda函数发送订阅，但不应该重新创建主题本身。

下面是我的代码：

from troposphere import FindInMap, GetAtt, Join, Output
from troposphere import Template, Ref
from troposphere.awslambda import Function, Code, Permission
from troposphere.sns import Topic, SubscriptionResource

folder_names = ["welt", "jukin"]

t = Template()

t.set_version("2010-09-09")

t.add_mapping("MapperToTenantId",
              {
                  u'welt': {'id': u't-012'},
                  u'jukin': {'id': u't-007'}
              }
              )

t.add_mapping("LambdaExecutionRole",
                {u'lambda-execution-role': {u'ARN': u'arn:aws:iam::498129003450:role/service-role/lambda_execution_role'}}
            )

code = [
    "def lambda_handler(event, context):\n",
    "    message = event[‘Records’][0][‘Sns’][‘Message’]\n",
    "    print(“From SNS: “ + message)\n",
    "    return message\n"
]


for cp in folder_names:
    lambda_function = t.add_resource(Function(
        f"{cp}MapperLambda",
        Code=Code(
        ZipFile=Join("", code)
    ),
    Handler="index.handler",
    Role=FindInMap("LambdaExecutionRole", "lambda-execution-role", "ARN"),
    Runtime="python3.6",
    )
    )

    t.add_resource(Permission(
        f"InvokeLambda{cp}Permission",
        FunctionName=GetAtt(lambda_function, "Arn"),
        Action="lambda:InvokeFunction",
        SourceArn='arn:aws:sns:us-west-2:498129003450:IngestStateTopic',
        Principal="sns.amazonaws.com"
    ))

    t.add_resource(SubscriptionResource(
        EndPoint=GetAtt(lambda_function, "Arn"),
        Protocol='lambda',
        TopicArn='arn:aws:sns:us-west-2:498129003450:IngestStateTopic'
    ))



with open('mapper_cf.yaml', 'w') as y:
    y.write(t.to_yaml())

我得到了下面的错误，但我无法找到解决方法：

Traceback (most recent call last):
  File "create_cloudformation.py", line 54, in <module>
    TopicArn='arn:aws:sns:us-west-2:498129003450:IngestStateTopic'
TypeError: __init__() missing 1 required positional argument: 'title'

在对流层中这是可能的吗？我不想在云形成中硬编码块，但我想在对流层中生成它。

这有可能做到吗？

请给我一些提示。

Answer 1

您得到的错误与未指定标题字符串有关。试试这个：

t.add_resource(SubscriptionResource(
    f"{cp}Subscription",
    EndPoint=GetAtt(lambda_function, "Arn"),
    Protocol='lambda',
    TopicArn='arn:aws:sns:us-west-2:498129003450:IngestStateTopic'
))