# CDK Construct Library for Amazon Simple Notification Service Subscriptions
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This library provides constructs for adding subscriptions to an Amazon SNS topic.
Subscriptions can be added by calling the `.addSubscription(...)` method on the topic.
## Subscriptions
Subscriptions can be added to the following endpoints:
* HTTPS
* Amazon SQS
* AWS Lambda
* Email
* SMS
Subscriptions to Amazon SQS and AWS Lambda can be added on topics across regions.
Create an Amazon SNS Topic to add subscriptions.
```python
my_topic = sns.Topic(self, "MyTopic")
```
### HTTPS
Add an HTTP or HTTPS Subscription to your topic:
```python
my_topic = sns.Topic(self, "MyTopic")
my_topic.add_subscription(subscriptions.UrlSubscription("https://foobar.com/"))
```
The URL being subscribed can also be [tokens](https://docs.aws.amazon.com/cdk/latest/guide/tokens.html), that resolve
to a URL during deployment. A typical use case is when the URL is passed in as a [CloudFormation
parameter](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/parameters-section-structure.html). The
following code defines a CloudFormation parameter and uses it in a URL subscription.
```python
my_topic = sns.Topic(self, "MyTopic")
url = CfnParameter(self, "url-param")
my_topic.add_subscription(subscriptions.UrlSubscription(url.value_as_string))
```
### Amazon SQS
Subscribe a queue to your topic:
```python
my_queue = sqs.Queue(self, "MyQueue")
my_topic = sns.Topic(self, "MyTopic")
my_topic.add_subscription(subscriptions.SqsSubscription(my_queue))
```
KMS key permissions will automatically be granted to SNS when a subscription is made to
an encrypted queue.
Note that subscriptions of queues in different accounts need to be manually confirmed by
reading the initial message from the queue and visiting the link found in it.
### AWS Lambda
Subscribe an AWS Lambda function to your topic:
```python
import aws_cdk.aws_lambda as lambda_
# my_function: lambda.Function
my_topic = sns.Topic(self, "myTopic")
my_topic.add_subscription(subscriptions.LambdaSubscription(my_function))
```
### Email
Subscribe an email address to your topic:
```python
my_topic = sns.Topic(self, "MyTopic")
my_topic.add_subscription(subscriptions.EmailSubscription("foo@bar.com"))
```
The email being subscribed can also be [tokens](https://docs.aws.amazon.com/cdk/latest/guide/tokens.html), that resolve
to an email address during deployment. A typical use case is when the email address is passed in as a [CloudFormation
parameter](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/parameters-section-structure.html). The
following code defines a CloudFormation parameter and uses it in an email subscription.
```python
my_topic = sns.Topic(self, "Topic")
email_address = CfnParameter(self, "email-param")
my_topic.add_subscription(subscriptions.EmailSubscription(email_address.value_as_string))
```
Note that email subscriptions require confirmation by visiting the link sent to the
email address.
### SMS
Subscribe an sms number to your topic:
```python
my_topic = sns.Topic(self, "Topic")
my_topic.add_subscription(subscriptions.SmsSubscription("+15551231234"))
```
The number being subscribed can also be [tokens](https://docs.aws.amazon.com/cdk/latest/guide/tokens.html), that resolve
to a number during deployment. A typical use case is when the number is passed in as a [CloudFormation
parameter](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/parameters-section-structure.html). The
following code defines a CloudFormation parameter and uses it in an sms subscription.
```python
my_topic = sns.Topic(self, "Topic")
sms_number = CfnParameter(self, "sms-param")
my_topic.add_subscription(subscriptions.SmsSubscription(sms_number.value_as_string))
```