This blog will show you how to integrate Lambda and slack. You’ll receive important notifications in the slack channel. The following task will be accomplished.
Incoming webhook in slack
Create a Lambda function that sends the notification directly to the slack.
Subscribe to the SNS Topic by making the Lambda function available.
Set up an alarm on the EC2 instance
Prerequisites:
You need to have a slack bank account
A running EC2 instance
Step by step guide to integrating Lambda with Slack

Task 1: Create an Incoming webhook in slack
Step 1: Open your slack app and look at the scenario below

Step 2: Click below on the team name

Step 3: Click on App and Custom Integration to open a popup menu.

Step 4: Search for the Slack application site. Type “incoming” into the search box, and then select the Incoming Webhooks option.

Step 5: Install the app within your team.

Step 6: Select the channel, then click on Add Incoming Webhook

Step 7: Now the Incoming Webhook has been created.
Step 8: You only need a Webhook URL, which you can find below. You can customize name and image of sender and save the setting.

Step 9: We will use Webhook URL in Lambda Function

Task 2: Create a Lambda function that sends the notification email to the slack.

Step 1: Visit AWS Lambda Console, and click on Get Started Right Now.

Step 2: Skip the Blueprint

Step 3: Enter Name and Description of your Lambda function.

Step 4: Go to the link https://s3-us-west-2.amazonaws.com/cloudthat.training/Lambda-slack-integration/lambd-slack-Integraion.dat and copy the code in the editor.
Step 5: Create a basic Execution Role for lambda

Step 6: Leave all other fields blank and click on Next.
Step 7: Go through the function and click on Create Function.
Step 8: Create your function and then set the value of your webhook URL to “slack_url”.

Task 3: Subscribe the Lambda function to the SNS Topic.

Step 1: Click on Create Topic in SNS.

Step 2: Fill in the information as shown below.

Step 3: Next, we will create a subscription to the lambda function. Click on Create Subscription.

Step 4: Choose Lambda Function to be your protocol and Endpoint to be your lambda function’s ARN.

Step 5: Now your Function is read and you will receive notifications from SNS.
Step 6: Click on Action to test and choose Configure test event.

Step 7: You can get a sample event from following link https://s3-us-west-2.amazonaws.com/cloudthat.training/Lambda-slack-integration/test-lambda.dat and you can check Message in slack.

Task 4: Create an alarm on the EC2 instance

Step 1: Click on Alarm to create an alarm at your EC2 Instance.

Step 2: Click on “Create Alarm” to activate the window.

Step 3: Your alarm has been set.
Step 4: We have given the Average CPU Utilization at 85 %, but you can also put it at 1% if you need an alarm quickly.
Step 5: If your CPU goes above threshold value, you will receive a message in Slack.

We have now set up a lambda function that sends Cloudwatch alerts through SNS to Slack. You can also post comments or ask questions to the forum.clodthat.com.
We are grateful.

Cleanup:
Lambda Function
SNS Topic
EC2 Alarm