SNS notification types (email, SMS, Lambda) in AWS - Mini Project: Build & Apply

SNS Notification Types (Email, SMS, Lambda)

📖 Scenario: You are setting up a notification system for a small online store. When an order is placed, the system should notify the store owner by email, send a text message to the manager, and trigger a Lambda function to update the inventory.

🎯 Goal: Create an AWS SNS topic with three subscriptions: one for email notifications, one for SMS notifications, and one that triggers a Lambda function.

📋 What You'll Learn

Create an SNS topic named OrderNotifications.

Subscribe an email endpoint [e-mail] to the topic.

Subscribe an SMS endpoint [phone] to the topic.

Subscribe a Lambda function named UpdateInventoryFunction to the topic.

💡 Why This Matters

🌍 Real World

SNS topics are used to send notifications to multiple endpoints like email, SMS, and Lambda functions in real-world applications such as order processing, alerts, and system monitoring.

💼 Career

Understanding how to configure SNS with different subscription types and Lambda integration is essential for cloud engineers and developers working with AWS event-driven architectures.

1

Create the SNS topic

Create an SNS topic named OrderNotifications using AWS CloudFormation syntax.

AWS

# Your code here to create the SNS topic named OrderNotifications

Hint

Use the AWS::SNS::Topic resource type and set TopicName to OrderNotifications.

2

Add email and SMS subscriptions

Add two subscriptions to the OrderNotifications topic: one email subscription with endpoint [e-mail] and one SMS subscription with endpoint [phone].

AWS

Resources:
  OrderNotifications:
    Type: AWS::SNS::Topic
    Properties:
      TopicName: OrderNotifications
# Add email and SMS subscriptions below

Hint

Use the Subscription property with a list of subscriptions. Each subscription needs a Protocol and an Endpoint.

3

Add Lambda function resource

Create a Lambda function resource named UpdateInventoryFunction with runtime python3.12 and handler index.handler. Use a placeholder for the code with inline code "exports.handler = async () => {};".

AWS

Resources:
  OrderNotifications:
    Type: AWS::SNS::Topic
    Properties:
      TopicName: OrderNotifications
      Subscription:
        - Protocol: email
          Endpoint: [e-mail]
        - Protocol: sms
          Endpoint: [phone]
# Add Lambda function resource below

Hint

Define the Lambda function with AWS::Lambda::Function. Use ZipFile for inline code. You must specify a valid Role ARN (use a placeholder ARN).

4

Subscribe Lambda function to SNS topic

Add a subscription to the OrderNotifications topic that triggers the Lambda function UpdateInventoryFunction. Use protocol lambda and the function's ARN reference.

AWS

Resources:
  OrderNotifications:
    Type: AWS::SNS::Topic
    Properties:
      TopicName: OrderNotifications
      Subscription:
        - Protocol: email
          Endpoint: [e-mail]
        - Protocol: sms
          Endpoint: [phone]
# Add Lambda subscription below
  UpdateInventoryFunction:
    Type: AWS::Lambda::Function
    Properties:
      FunctionName: UpdateInventoryFunction
      Runtime: python3.12
      Handler: index.handler
      Code:
        ZipFile: |
          exports.handler = async () => {};
      Role: arn:aws:iam::123456789012:role/lambda-execution-role

Hint

Add a subscription with Protocol: lambda and use !GetAtt UpdateInventoryFunction.Arn to reference the Lambda ARN.

Practice

1. Which of the following is NOT a valid protocol for an AWS SNS subscription?

easy

A. email

B. sms

C. lambda

D. ftp

Solution

1. Step 1: Review SNS supported protocols

   AWS SNS supports protocols like email, sms, and lambda for subscriptions.

2. Step 2: Identify unsupported protocol

   FTP is not supported as a protocol for SNS subscriptions.

3. Final Answer:

   ftp -> Option D

4. Quick Check:

   Supported protocols exclude ftp [OK]

Hint: Remember SNS supports email, sms, lambda but not ftp [OK]

Common Mistakes:

• Confusing FTP as supported protocol
• Thinking HTTP is the only protocol
• Mixing SNS with S3 protocols

2. Which is the correct way to specify an SMS subscription protocol in AWS SNS?

easy

A. Protocol: 'sms', Endpoint: '[e-mail]'

B. Protocol: 'email', Endpoint: '[phone]'

C. Protocol: 'sms', Endpoint: '[phone]'

D. Protocol: 'lambda', Endpoint: '[phone]'

Solution

1. Step 1: Understand protocol and endpoint types

   For SMS, protocol must be 'sms' and endpoint is a phone number with country code.

2. Step 2: Match correct protocol and endpoint

   Protocol: 'sms', Endpoint: '[phone]' correctly uses 'sms' protocol and a phone number endpoint.

3. Final Answer:

   Protocol: 'sms', Endpoint: '[phone]' -> Option C

4. Quick Check:

   SMS needs phone number endpoint [OK]

Hint: SMS protocol requires phone number endpoint format [OK]

Common Mistakes:

• Using email as protocol for SMS
• Using email address as SMS endpoint
• Using lambda protocol with phone number

3. Given this AWS SNS subscription code snippet:

sns.subscribe({
  Protocol: 'lambda',
  Endpoint: 'arn:aws:lambda:us-east-1:123456789012:function:ProcessMessage'
});

What happens when a message is published to this SNS topic?

medium

A. The Lambda function 'ProcessMessage' is invoked with the message payload.

B. The message is sent as an SMS to the Lambda function ARN.

C. The message is sent as an email to the Lambda function.

D. The subscription will fail because Lambda cannot be an endpoint.

Solution

1. Step 1: Identify protocol and endpoint meaning

   Protocol 'lambda' means SNS invokes the specified Lambda function ARN when a message is published.

2. Step 2: Understand message delivery behavior

   The Lambda function 'ProcessMessage' is called with the message payload as input.

3. Final Answer:

   The Lambda function 'ProcessMessage' is invoked with the message payload. -> Option A

4. Quick Check:

   Lambda protocol triggers function invocation [OK]

Hint: Lambda protocol triggers function call, not email or SMS [OK]

Common Mistakes:

• Thinking Lambda receives email or SMS
• Assuming subscription fails
• Confusing endpoint ARN with phone/email

4. You created an SNS subscription with protocol 'email' but the subscriber never receives messages. What is the most likely cause?

medium

A. The email address was not confirmed by the subscriber.

B. The SNS topic does not support email protocol.

C. The subscription endpoint was set to a phone number.

D. Lambda function is not attached to the subscription.

Solution

1. Step 1: Understand email subscription confirmation

   Email subscriptions require the recipient to confirm by clicking a link in a confirmation email.

2. Step 2: Identify common cause of no delivery

   If the email is not confirmed, SNS will not send notifications to that address.

3. Final Answer:

   The email address was not confirmed by the subscriber. -> Option A

4. Quick Check:

   Email subscriptions need confirmation [OK]

Hint: Email subscriptions require confirmation before delivery [OK]

Common Mistakes:

• Assuming SNS does not support email
• Confusing phone number as email endpoint
• Expecting Lambda involvement in email subscription

5. You want to send an SMS notification and also trigger a Lambda function whenever a message is published to an SNS topic. How should you configure the subscriptions?

hard

A. Create one subscription with protocol 'email' and endpoint as phone number, and another with protocol 'lambda' and endpoint as Lambda ARN.

B. Create one subscription with protocol 'sms' and endpoint as phone number, and another with protocol 'lambda' and endpoint as Lambda ARN.

C. Create one subscription with protocol 'lambda' and endpoint as phone number, and another with protocol 'sms' and endpoint as Lambda ARN.

D. Create one subscription with protocol 'sms' and endpoint as Lambda ARN, and another with protocol 'lambda' and endpoint as phone number.

Solution

1. Step 1: Understand protocol and endpoint matching

   SMS protocol requires a phone number endpoint; Lambda protocol requires Lambda function ARN.

2. Step 2: Configure two subscriptions correctly

   Create one subscription with protocol 'sms' and phone number endpoint, and another with protocol 'lambda' and Lambda ARN endpoint.

3. Final Answer:

   Create one subscription with protocol 'sms' and endpoint as phone number, and another with protocol 'lambda' and endpoint as Lambda ARN. -> Option B

4. Quick Check:

   Match protocol to correct endpoint type [OK]

Hint: Match SMS to phone number, Lambda to function ARN [OK]

Common Mistakes:

• Mixing endpoints and protocols
• Using email protocol for SMS
• Assigning Lambda ARN as SMS endpoint