AWS Cost Monitor

A CloudFormation template for AWS cost monitoring with Slack or Microsoft Teams notifications developed by DNX Solutions.

Overview

AWS Cost Monitor is a serverless solution that provides daily or scheduled cost monitoring and forecasting for your AWS account. It sends automated notifications to a Slack channel or Microsoft Teams channel with real-time cost data.

The tool helps teams maintain visibility of AWS costs, track budget trends, and quickly identify unexpected spending increases.

Features

• Current Month Costs: Reports total usage costs for the current month
• Cost Forecasting: Predicts end-of-month costs based on current usage patterns
• Trend Analysis: Compares current costs with previous month's spending
• Credit Tracking: Shows how many AWS credits have been applied this month
• Customizable Schedule: Run on your preferred cadence (daily, specific weekdays, etc.)
• Serverless Architecture: No infrastructure to maintain
• Simple Deployment: Single-click deployment through CloudFormation
• Multiple Notification Options: Support for both Slack and Microsoft Teams

Architecture

The solution uses the following AWS services:

• AWS Lambda: Executes the cost analysis code
• AWS Cost Explorer API: Retrieves current and forecasted cost data
• Amazon EventBridge: Schedules regular cost reporting
• AWS IAM: Manages permissions for accessing cost data
• Webhook Integrations: Delivers notifications to your team via Slack or Microsoft Teams

Installation

Prerequisites

• An AWS account with permissions to create Lambda functions, IAM roles, and EventBridge rules
• A Slack workspace with permissions to create webhook integrations (for Slack notifications)
• A Microsoft Teams team with permissions to create incoming webhooks (for Teams notifications)

Deployment Steps

For Slack Notifications

1. Create a Slack webhook URL:

   • Go to your Slack workspace's App Directory
   • Create a new app or use an existing one
   • Enable Incoming Webhooks
   • Create a new webhook for the channel where you want to receive notifications
   • Copy the webhook URL

2. Deploy the CloudFormation template (forecast.yml):

   • Log in to the AWS Console of your Management account (the account that manages the AWS Organization)
   • Change to us-east-1 region (N. Virginia)
   • Navigate to CloudFormation
   • Click "Create stack" > "With new resources (standard)"
   • Upload the template file or use an S3 URL
   • Fill in the parameters:
     • SlackWebhookUrl: The webhook URL from step 1
     • NotificationTime: The cron expression for when to send notifications

3. Wait for the stack creation to complete (typically 1-2 minutes)

4. Verify the installation by checking your Slack channel for cost notifications

For Microsoft Teams Notifications

1. Create a Microsoft Teams webhook URL:

   • Go to the Teams channel where you want to receive notifications
   • Click the "..." menu next to the channel name, click "Manage Channel"
   • Under "Connectors", click "Edit"
   • Find "Incoming Webhook" and click "Configure"
   • Provide a name for the webhook (e.g., "AWS Cost Monitor")
   • Optionally upload an icon for the webhook
   • Click "Create" and copy the webhook URL

2. Deploy the CloudFormation template (forecast-teams.yml):

   • Log in to the AWS Console of your Management account (the account that manages the AWS Organization)
   • Change to us-east-1 region (N. Virginia)
   • Navigate to CloudFormation
   • Click "Create stack" > "With new resources (standard)"
   • Upload the template file or use an S3 URL
   • Fill in the parameters:
     • TeamsWebhookUrl: The webhook URL from step 1
     • NotificationTime: The cron expression for when to send notifications

3. Wait for the stack creation to complete (typically 1-2 minutes)

4. Verify the installation by checking your Microsoft Teams channel for cost notifications

Configuration Options

Slack Template Parameters

The Slack CloudFormation template (forecast.yml) accepts the following parameters:

Parameter	Description	Default
SlackWebhookUrl	The Slack webhook URL to post cost notifications	(Required)
NotificationTime	Cron expression for when to send notifications	0 9 * * ? * (9 AM UTC daily)

Microsoft Teams Template Parameters

The Microsoft Teams CloudFormation template (forecast-teams.yml) accepts the following parameters:

Parameter	Description	Default
TeamsWebhookUrl	The Microsoft Teams webhook URL to post cost notifications	(Required)
NotificationTime	Cron expression for when to send notifications	0 9 * * ? * (9 AM UTC daily)

Cost Considerations

This solution uses the following AWS services that may incur charges:

• AWS Lambda: The function executes briefly once per scheduled run. This typically stays within the AWS Free Tier.
• AWS Cost Explorer API: The API has a cost associated with each API call. This solution makes three API calls per execution.

Overall, the cost to run this solution should be minimal (typically less than $1 per month).

Customization

Changing the Schedule

To change when notifications are sent, update the NotificationTime parameter with a different cron expression:

• Daily at 9 AM UTC: 0 9 * * ? *
• Weekdays at 9 AM UTC: 0 9 ? * MON-FRI *
• Every 6 hours: 0 0/6 * * ? *

Adding Additional Metrics

The Lambda function can be modified to include additional cost metrics or filtering by:

• AWS service
• Tag
• Account (for AWS Organizations)
• Region

Troubleshooting

Common issues:

1. No notifications received:

   • Check that the webhook URL is correct (Slack or Teams)
   • Verify the Lambda execution role has proper permissions
   • Check Lambda CloudWatch logs for errors

2. Missing or incorrect data:

   • Ensure Cost Explorer is enabled in your account
   • The Cost Explorer API has a 24-hour data freshness delay
   • Verify IAM permissions include ce:GetCostForecast and ce:GetCostAndUsage

License

This project is licensed under the MIT License - see the LICENSE file for details.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

About DNX Solutions

DNX Solutions specializes in AWS Cloud solutions and services, helping businesses leverage the power of cloud computing.