Gemini CLIの組み込みskill-creatorを使ってみた

---
name: aws-unused-resource-searcher
description: AWS アカウント内のリソース利用状況を分析し、一定期間アクティビティが確認されない EC2、EBS、NAT Gateway、ALB、NLB などの未使用リソース候補を検出する。CloudWatch メトリクスおよび AWS API 情報を用いて、削除可能性を一覧で出力する。
---

# AWS Unused Resource Searcher

## Overview

This skill helps identify potentially unused AWS resources in a specific region to assist with cost optimization. It uses a bundled Python script to scan for resources that show signs of inactivity.

## Usage

To use this skill, run the provided script `scripts/find_unused_resources.py`.

### Prerequisites
- AWS Credentials configured in the environment (e.g., via `~/.aws/credentials` or environment variables).
- Python 3 with `boto3` installed.

### Command

# Run the scanner for a specific region (e.g., us-east-1)
./aws-unused-resource-searcher/scripts/find_unused_resources.py --region <region_name>

## Resource Checks

The script performs the following checks:

### 1. EC2 Instances
- **Stopped Instances**: Lists any instance currently in the 'stopped' state.
- **Low CPU Utilization**: Lists 'running' instances with average CPU utilization < 1% over the last 7 days.

### 2. EBS Volumes
- **Unattached Volumes**: Lists any volume with status 'available' (not attached to any instance).

### 3. Elastic IPs (EIP)
- **Unassociated IPs**: Lists Elastic IPs that are not associated with any instance or network interface.

## Next Steps

After identifying unused resources:
1.  **Verify**: Manually verify if the resource is indeed not needed (e.g., it might be a cold standby).
2.  **Snapshot**: Consider creating a snapshot of EBS volumes before deletion.
3.  **Delete/Release**: Remove the resources to save costs.

#!/usr/bin/env python3
import boto3
import argparse
import sys
from datetime import datetime, timedelta

def get_boto3_client(service, region):
    return boto3.client(service, region_name=region)

def check_ec2_instances(region):
    print(f"--- Checking EC2 Instances in {region} ---")
    ec2 = get_boto3_client('ec2', region)
    cw = get_boto3_client('cloudwatch', region)

    try:
        response = ec2.describe_instances(Filters=[{'Name': 'instance-state-name', 'Values': ['running', 'stopped']}])
        instances = []
        for r in response['Reservations']:
            instances.extend(r['Instances'])

        unused_instances = []

        for i in instances:
            instance_id = i['InstanceId']
            state = i['State']['Name']
            name = next((t['Value'] for t in i.get('Tags', []) if t['Key'] == 'Name'), instance_id)

            if state == 'stopped':
                unused_instances.append(f"[STOPPED] {name} ({instance_id}) is stopped.")
            elif state == 'running':
                # Check CPU utilization for the last 7 days
                end_time = datetime.utcnow()
                start_time = end_time - timedelta(days=7)

                try:
                    metrics = cw.get_metric_statistics(
                        Namespace='AWS/EC2',
                        MetricName='CPUUtilization',
                        Dimensions=[{'Name': 'InstanceId', 'Value': instance_id}],
                        StartTime=start_time,
                        EndTime=end_time,
                        Period=86400, # 1 day
                        Statistics=['Average']
                    )

                    if metrics['Datapoints']:
                        avg_cpu = sum([d['Average'] for d in metrics['Datapoints']]) / len(metrics['Datapoints'])
                        if avg_cpu < 1.0:
                             unused_instances.append(f"[LOW CPU] {name} ({instance_id}) has < 1% avg CPU over 7 days ({avg_cpu:.2f}%).")
                    else:
                         # No data often means it hasn't been running long or monitoring is off
                         pass 
                except Exception as e:
                    print(f"  Warning: Could not get metrics for {instance_id}: {e}")

        if unused_instances:
            for item in unused_instances:
                print(item)
        else:
            print("No clearly unused EC2 instances found.")

    except Exception as e:
        print(f"Error checking EC2 instances: {e}")

def check_ebs_volumes(region):
    print(f"\n--- Checking EBS Volumes in {region} ---")
    ec2 = get_boto3_client('ec2', region)

    try:
        response = ec2.describe_volumes(Filters=[{'Name': 'status', 'Values': ['available']}])
        volumes = response['Volumes']

        if volumes:
            for v in volumes:
                vol_id = v['VolumeId']
                size = v['Size']
                created = v['CreateTime'].strftime('%Y-%m-%d')
                print(f"[UNATTACHED] {vol_id} ({size} GiB) created on {created} is available.")
        else:
            print("No unattached EBS volumes found.")

    except Exception as e:
        print(f"Error checking EBS volumes: {e}")

def check_eips(region):
    print(f"\n--- Checking Elastic IPs in {region} ---")
    ec2 = get_boto3_client('ec2', region)

    try:
        response = ec2.describe_addresses()
        eips = response['Addresses']

        found = False
        for eip in eips:
            if 'AssociationId' not in eip:
                print(f"[UNASSOCIATED] {eip['PublicIp']} is not associated with any resource.")
                found = True

        if not found:
            print("No unassociated Elastic IPs found.")

    except Exception as e:
        print(f"Error checking Elastic IPs: {e}")

def main():
    parser = argparse.ArgumentParser(description="Find unused AWS resources.")
    parser.add_argument("--region", type=str, required=True, help="AWS Region to check")
    args = parser.parse_args()

    print(f"Scanning for unused resources in region: {args.region}\n")

    check_ec2_instances(args.region)
    check_ebs_volumes(args.region)
    check_eips(args.region)

    print("\nScan complete.")

if __name__ == "__main__":
    main()

#!/usr/bin/env python3
import boto3
import argparse
import sys
from datetime import datetime, timedelta, timezone

def get_boto3_client(service, region):
    return boto3.client(service, region_name=region)

def get_metric_sum(cw_client, namespace, metric_name, dimensions, start_time, end_time):
    try:
        metrics = cw_client.get_metric_statistics(
            Namespace=namespace,
            MetricName=metric_name,
            Dimensions=dimensions,
            StartTime=start_time,
            EndTime=end_time,
            Period=86400 * 7, # 7 days as one period to get total sum
            Statistics=['Sum']
        )
        if metrics['Datapoints']:
            return metrics['Datapoints'][0]['Sum']
        return 0.0
    except Exception as e:
        print(f"  Warning: Could not get metrics for {metric_name}: {e}")
        return None

def check_ec2_instances(region):
    print(f"--- Checking EC2 Instances in {region} ---")
    ec2 = get_boto3_client('ec2', region)
    cw = get_boto3_client('cloudwatch', region)

    try:
        response = ec2.describe_instances(Filters=[{'Name': 'instance-state-name', 'Values': ['running', 'stopped']}])
        instances = []
        for r in response['Reservations']:
            instances.extend(r['Instances'])

        unused_instances = []

        for i in instances:
            instance_id = i['InstanceId']
            state = i['State']['Name']
            name = next((t['Value'] for t in i.get('Tags', []) if t['Key'] == 'Name'), instance_id)

            if state == 'stopped':
                unused_instances.append(f"[STOPPED] {name} ({instance_id}) is stopped.")
            elif state == 'running':
                # Check CPU utilization for the last 7 days
                end_time = datetime.now(timezone.utc)
                start_time = end_time - timedelta(days=7)

                try:
                    metrics = cw.get_metric_statistics(
                        Namespace='AWS/EC2',
                        MetricName='CPUUtilization',
                        Dimensions=[{'Name': 'InstanceId', 'Value': instance_id}],
                        StartTime=start_time,
                        EndTime=end_time,
                        Period=86400, # 1 day
                        Statistics=['Average']
                    )

                    if metrics['Datapoints']:
                        avg_cpu = sum([d['Average'] for d in metrics['Datapoints']]) / len(metrics['Datapoints'])
                        if avg_cpu < 1.0:
                             unused_instances.append(f"[LOW CPU] {name} ({instance_id}) has < 1% avg CPU over 7 days ({avg_cpu:.2f}%).")
                    else:
                         # No data often means it hasn't been running long or monitoring is off
                         pass 
                except Exception as e:
                    print(f"  Warning: Could not get metrics for {instance_id}: {e}")

        if unused_instances:
            for item in unused_instances:
                print(item)
        else:
            print("No clearly unused EC2 instances found.")

    except Exception as e:
        print(f"Error checking EC2 instances: {e}")

def check_ebs_volumes(region):
    print(f"\n--- Checking EBS Volumes in {region} ---")
    ec2 = get_boto3_client('ec2', region)

    try:
        response = ec2.describe_volumes(Filters=[{'Name': 'status', 'Values': ['available']}])
        volumes = response['Volumes']

        if volumes:
            for v in volumes:
                vol_id = v['VolumeId']
                size = v['Size']
                # CreateTime is already timezone-aware in boto3
                created = v['CreateTime'].strftime('%Y-%m-%d')
                print(f"[UNATTACHED] {vol_id} ({size} GiB) created on {created} is available.")
        else:
            print("No unattached EBS volumes found.")

    except Exception as e:
        print(f"Error checking EBS volumes: {e}")

def check_eips(region):
    print(f"\n--- Checking Elastic IPs in {region} ---")
    ec2 = get_boto3_client('ec2', region)

    try:
        response = ec2.describe_addresses()
        eips = response['Addresses']

        found = False
        for eip in eips:
            if 'AssociationId' not in eip:
                print(f"[UNASSOCIATED] {eip['PublicIp']} is not associated with any resource.")
                found = True

        if not found:
            print("No unassociated Elastic IPs found.")

    except Exception as e:
        print(f"Error checking Elastic IPs: {e}")

def check_albs(region):
    print(f"\n--- Checking ALBs in {region} ---")
    elbv2 = get_boto3_client('elbv2', region)
    cw = get_boto3_client('cloudwatch', region)

    try:
        response = elbv2.describe_load_balancers()
        albs = [lb for lb in response['LoadBalancers'] if lb['Type'] == 'application']

        unused_albs = []
        end_time = datetime.now(timezone.utc)
        start_time = end_time - timedelta(days=7)

        for alb in albs:
            arn = alb['LoadBalancerArn']
            name = alb['LoadBalancerName']
            # Metric dimensions for ALB require the full LoadBalancer suffix (e.g., app/my-load-balancer/50dc6c495c0c9188)
            # The ARN format is arn:aws:elasticloadbalancing:region:account-id:loadbalancer/app/load-balancer-name/load-balancer-id
            lb_dimension_value = "/".join(arn.split("/")[-3:])

            req_count = get_metric_sum(cw, 'AWS/ApplicationELB', 'RequestCount', [{'Name': 'LoadBalancer', 'Value': lb_dimension_value}], start_time, end_time)

            if req_count is not None and req_count == 0:
                unused_albs.append(f"[NO TRAFFIC] ALB {name} has 0 requests over the last 7 days.")

        if unused_albs:
            for item in unused_albs:
                print(item)
        else:
            print("No unused ALBs found (based on 0 requests in 7 days).")

    except Exception as e:
        print(f"Error checking ALBs: {e}")

def check_nat_gateways(region):
    print(f"\n--- Checking NAT Gateways in {region} ---")
    ec2 = get_boto3_client('ec2', region)
    cw = get_boto3_client('cloudwatch', region)

    try:
        response = ec2.describe_nat_gateways(Filters=[{'Name': 'state', 'Values': ['available']}])
        nat_gateways = response['NatGateways']

        unused_nats = []
        end_time = datetime.now(timezone.utc)
        start_time = end_time - timedelta(days=7)

        for nat in nat_gateways:
            nat_id = nat['NatGatewayId']
            # Name tag
            name = next((t['Value'] for t in nat.get('Tags', []) if t['Key'] == 'Name'), nat_id)

            # Check traffic metrics
            bytes_in = get_metric_sum(cw, 'AWS/NATGateway', 'BytesInFromSource', [{'Name': 'NatGatewayId', 'Value': nat_id}], start_time, end_time)
            bytes_out = get_metric_sum(cw, 'AWS/NATGateway', 'BytesOutToDestination', [{'Name': 'NatGatewayId', 'Value': nat_id}], start_time, end_time)

            total_bytes = (bytes_in or 0) + (bytes_out or 0)

            if total_bytes == 0:
                unused_nats.append(f"[NO TRAFFIC] NAT Gateway {name} ({nat_id}) has 0 bytes processed over the last 7 days.")

        if unused_nats:
            for item in unused_nats:
                print(item)
        else:
            print("No unused NAT Gateways found (based on 0 bytes in 7 days).")

    except Exception as e:
        print(f"Error checking NAT Gateways: {e}")

def main():
    parser = argparse.ArgumentParser(description="Find unused AWS resources.")
    parser.add_argument("--region", type=str, required=True, help="AWS Region to check")
    args = parser.parse_args()

    print(f"Scanning for unused resources in region: {args.region}\n")

    check_ec2_instances(args.region)
    check_ebs_volumes(args.region)
    check_eips(args.region)
    check_albs(args.region)
    check_nat_gateways(args.region)

    print("\nScan complete.")

if __name__ == "__main__":