Drift Detector

Project Overview

This Go application detects configuration drift between AWS EC2 instances and their corresponding Terraform configurations. It compares the actual state of an instance in AWS against its definition in a Terraform state file or HCL configuration, identifying discrepancies in specified attributes.

Setup and Installation

• Ensure Go 1.19+ is installed: https://go.dev/doc/install
• Configure AWS credentials (e.g., via environment variables AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_REGION, or shared credentials file ~/.aws/credentials): https://docs.aws.amazon.com/sdk-for-go/v2/developer-guide/configure-gosdk.html, aws configure command can also be used to set up credentials.
• Clone the repository: git clone <repository-url> (Replace <repository-url> with the actual URL once available)
• Navigate to the project directory: cd driftdetector
• Build the application: go build ./cmd/driftdetector

Running the Application

The application can be run in various ways depending on your requirements:

# Basic usage: Check drift for a specific instance using HCL config
./driftdetector --instance-ids i-xxxxxxxxxxxxxxxxx --config-path ./configs/sample.tf

# Check drift for multiple instances
./driftdetector --instance-ids i-xxxxxxxxxxxxxxxxx,i-yyyyyyyyyyyyyyyyy --config-path ./configs/sample.tf

# Check drift with controlled concurrency (limit to 2 instances at a time)
./driftdetector --instance-ids i-xxxxxxxxx,i-yyyyyyyyy,i-zzzzzzzzz --config-path ./configs/sample.tf --concurrency 2

# Output results in JSON format
./driftdetector --instance-ids i-xxxxxxxxxxxxxxxxx --config-path ./configs/sample.tf --output json

# Specify attributes to check
./driftdetector --instance-ids i-xxxxxxxxxxxxxxxxx --config-path ./configs/sample.tf --attributes instance_type,tags,security_groups

# Run in verbose mode
./driftdetector --instance-ids i-xxxxxxxxxxxxxxxxx --config-path ./configs/sample.tf --verbose