amcginlay / sns-webserver

Build a NodeJS webserver to support SNS http subscriptions

sns-webserver

Build a NodeJS webserver to support SNS http subscriptions

• Use us-east-1
• Create an Amazon Linux EC2 instance
• Use Instance Type t2.micro
• Use a public IP
• Configure the instance to use a role that permits remote access via Systems Manager (SSM) and full access to SNS
• Use a security group to open port 80
• Tags: Name=sns-demo
• Connect to sns-demo with SSM Session Manager and start the webserver as follows

sudo curl --silent --location https://rpm.nodesource.com/setup_14.x | sudo bash -
sudo yum -y install nodejs git
git clone https://github.com/amcginlay/sns-webserver.git ~/sns-webserver
cd ~/sns-webserver
npm update
sudo PORT=80 npm start

• Now the webserver is running, duplicate the browser tab containing the sns-demo SSM session
• Create the SNS topic

export AWS_DEFAULT_REGION=us-east-1
topic=$(aws sns create-topic \
  --name sns-demo-topic \
  --output text \
)

• Subscribe the webserver to the SNS topic using its public IP address (alternatively use an elastic IP or public DNSName)

myipaddress$($(curl --silent http://169.254.169.254/latest/meta-data/public-ipv4/))
subscription=$(aws sns subscribe \
  --topic-arn ${topic} \
  --protocol http \
  --return-subscription-arn \
  --notification-endpoint http://${myipaddress} \
  --output text \
)

• Look in the first browser tab. The webserver will have output the SNS Subscription Token. You'll need it for the next command
• Confirm the subscription

aws sns confirm-subscription --topic-arn ${topic} --token <SNS_SUBSCRIPTION_TOKEN>

• Create a publication event

aws sns publish --topic-arn ${topic} --message "this is a test"

• The webserver output will display the published message
• If you repeat the subscribe and confirm-subscription steps for another webserver then both will be notified of any publications
• You can remove a subscription as follows

aws sns unsubscribe --subscription-arn ${subscription}