Domain checker

This is a super basic application that runs on AWS Lambda and checks the availability status of a given domain name. It sends an email notification when (or IF) it gets released.

Checks are made using a simple whois lookup, trying to stay under the radar, as any other action like opening the URL in the browser could signal there's interest to the owners.

Components

This is composed of two parts:

• App: Written in go, can be run locally to confirm the domain in question is effectively detected as not available to start with.
• TF code: Builds and deploys the app to an AWS Lambda function, that is configured to run hourly and log the results to Clodwatch Logs. From there, a Cloudwatch Metric Filter looks for the text "DomainAvailable". If found, it sends an email to the pre-configured email.

Currently it sends an email every time it runs (i.e. hourly) if the domain is found available. It would have been better to have a "cooldown period", and only send emails every 2 days, for example. Unfortunately, it would have meant adding more innecessary components to the mix, increasing the overall solution complexity.

On the other hand, worst case scenario is that we get 8-10 email while we sleep, but we won't miss the news!

Important

This tool has only been tested with .com and .co.jp domains!

How to run this locally?

App

The application code is located in the app directory.

This is a standard Go application following conventional Go project structure.

A Makefile is provided with common operations:

make test: Run tests make build: Build app

View all available commands with make help.

Running the app

First, build the application from the app directory:

make build

Then run it with:

./bin/domain-checker check --domain domaintocheck.com

Terraform code

Note

Minimum Terraform version required: 1.11.4

Terraform code is located in the tf directory.

Prerequisites

AWS

Terraform configuration expects a local AWS SSO session named tf-admin is configured. Set this up with:

aws configure sso

Follow the instructions. When asked about the Session name, enter tf-admin (Recommended). If you want to use a different name, please ensure scripts and files are changed accordingly.

Important

Terraform code needs to create new IAM roles for Lambda functions. Thus, AWS PowerUserAccess role is insufficient - you'll need administrative privileges.

Statefile

Terraform is configured to store the state in a S3 bucket. To do so, rename the tf/backend-config.hcl.template file to tf/backend-config.hcl (remove the .template suffix), and point to a bucket that already exists.

The role for AWS must have the following IAM permissions on the bucket:

• s3:ListBucket on arn:aws:s3:::mybucket. At a minimum, this must be able to list the path where the state is stored.
• s3:GetObject on arn:aws:s3:::mybucket/path/to/my/key and arn:aws:s3:::mybucket/path/to/my/key.tflock (lockfile)
• s3:PutObject on arn:aws:s3:::mybucket/path/to/my/key and arn:aws:s3:::mybucket/path/to/my/key.tflock (lockfile)

Please refer to the S3 backend documentation for more details.

Deployment

1. Run make login to authenticate with SSO
2. Run source ./set-aws.sh to configure AWS credentials as environment variables for the S3 backend state.
3. (First time only) make init. This calls terraform init on the directory.
4. make plan. This will trigger the terraform plan command.
5. make apply. This will run the terraform apply