AWS Cost Monitoring & Budget Alert Automation

This project automates AWS cost monitoring and alerting using a serverless architecture powered by:

• AWS Budgets (for tracking spending thresholds)

• AWS Lambda (for processing alerts and generating daily reports)

• Amazon SNS (for email alerts)

• EventBridge (for scheduled daily reports)

• Slack Webhooks (for real-time notifications)

• Terraform (for full Infrastructure as Code) GitHub Link Repo

---

What It Does

✅ Sends a daily AWS cost summary to Slack via a configured Webhook URL
✅ Triggers email alerts via SNS when the AWS monthly budget threshold is exceeded
✅ Uses a Lambda function to process and format budget alerts before forwarding to subscribers

---

Technologies Used

• AWS Lambda

• AWS SNS

• AWS Budgets

• EventBridge (CloudWatch Scheduler)

• Slack Webhook

• Python 3.9

• Terraform

Setup Instructions

1. Clone the Repository

git clone https://github.com/yourusername/aws-cost-monitoring.git
cd aws-cost-monitoring

2. Generate a Slack Webhook URL

To receive cost alerts in Slack:

1. Go to your Slack workspace

1. Navigate to Apps and search for Incoming Webhooks

2. Click Add to Slack

1. Select a channel where messages should appear

1. Click Add Incoming Webhooks integration

2. Copy the Webhook URL provided (e.g., https://hooks.slack.com/services/...)

3. Provide the values of the following to variable.tf

slack_webhook_url     = "https://hooks.slack.com/services/..."
alert_email_address   = "your@email.com"

4. Deploy the Infrastructure

cd infra
terraform init
terraform plan
terraform apply --auto-approve

📬 Check your inbox to verify the SNS email subscription!

5. Configure the AWS Budget Manually

Go to the AWS Console → Budgets → Create a monthly cost budget manually with the following:

• Budget type: Cost

• Threshold: 80% or any value you prefer

• Budget Alert: SNS Topic created by Terraform (e.g., aws-budget-alerts)

• 

6. (Optional) Terraform Destroy

To remove the infrastructure when you're done testing:

terraform destroy

Troubleshooting: Overcoming Terraform & AWS SNS Issues

While deploying the cost management alert system using Terraform and AWS, I ran into a few stumbling blocks. Here’s how I worked through them and got everything running smoothly:

Problem 1: SNS Topic and Email Subscription Not Triggering

After running terraform apply, I expected my SNS topic and email subscription to be automatically created and verified. However, nothing appeared in my AWS SNS console, and I did not receive a confirmation email at the email address I provided(@proton.me).

Solution:

• I manually went to the AWS Console → SNS and created the topic and email subscription myself.

• I noticed that Proton Mail sometimes delays or blocks AWS confirmation emails, so I switched to Gmail: @gmail.com.

• After doing that, I received the email and confirmed the subscription successfully.

Problem 2: Terraform Didn't Detect My Manual Resources

Because I created the SNS topic and subscription manually, Terraform didn't recognise them in its state. This can cause inconsistencies.

Solution:

To bring the manually created resources under Terraform management, I used the terraform import command:

bashCopyEditterraform import aws_sns_topic.budget_alert arn:aws:sns:us-east-1:123456789012:budget_alert_topic

This told Terraform: “Hey, this resource already exists — manage it from now on.”

Problem 3: Lambda Notification Not Triggering

Even after the SNS and subscription were working, my Lambda function didn’t seem to trigger alerts.

Solution:

• I double-checked the SNS topic ARN being used in the Lambda code.

• Made sure the Lambda had publish permissions to that topic.

• Then manually tested the Lambda from the console to simulate a budget alert.

Lessons Learned

• Email deliverability matters — always test with a known-compatible provider like Gmail.

• Terraform isn't magic — if you go manual, you must bring resources back into state with import.

• SNS + Lambda + Slack/Email integrations can break silently. Always test each piece in isolation.