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local-app/python-tools/cross-organization/purge_sg_rules.py

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+#!/usr/bin/env python
+import boto3
+import argparse
+import sys
+from botocore.exceptions import ClientError
+
+# --- VERSIONING ---
+__version__ = "1.0.0"
+
+def purge_rules(group_id, region, profile, dry_run=True):
+    """
+    Removes all ingress and egress rules from the specified Security Group.
+    """
+    session = boto3.Session(profile_name=profile, region_name=region)
+    ec2 = session.client('ec2')
+
+    print(f"\n--- Purging Rules for {group_id} in {region} (Profile: {profile}) ---")
+    if dry_run:
+        print("[DRY-RUN] No changes will be made.")
+
+    try:
+        # 1. Describe the group to get current rules
+        response = ec2.describe_security_groups(GroupIds=[group_id])
+        sg = response['SecurityGroups'][0]
+
+        ingress = sg.get('IpPermissions', [])
+        egress = sg.get('IpPermissionsEgress', [])
+
+        # 2. Revoke Ingress
+        if ingress:
+            print(f"  Found {len(ingress)} ingress rule sets. Revoking...")
+            if not dry_run:
+                ec2.revoke_security_group_ingress(GroupId=group_id, IpPermissions=ingress)
+                print("  Successfully revoked all ingress rules.")
+        else:
+            print("  No ingress rules found.")
+
+        # 3. Revoke Egress
+        if egress:
+            print(f"  Found {len(egress)} egress rule sets. Revoking...")
+            if not dry_run:
+                ec2.revoke_security_group_egress(GroupId=group_id, IpPermissions=egress)
+                print("  Successfully revoked all egress rules.")
+        else:
+            print("  No egress rules found.")
+
+    except ClientError as e:
+        if e.response['Error']['Code'] == 'DryRunOperation':
+            print("[DRY-RUN] Permission check successful.")
+        else:
+            print(f"Error: {e}")
+            sys.exit(1)
+
+def main():
+    parser = argparse.ArgumentParser(description=f"SG Rule Purger v{__version__}")
+    parser.add_argument("--group-id", required=True, help="The ID of the security group (sg-xxxxxxxx)")
+    parser.add_argument("--region", required=True, help="AWS Region (e.g., us-east-1)")
+    parser.add_argument("--profile", required=True, help="AWS CLI Profile name")
+    parser.add_argument("--dry-run", action="store_true", default=False, help="Perform a dry run")
+
+    args = parser.parse_args()
+
+    # If --dry-run is not passed, it defaults to False. 
+    # But for safety, I've coded the function to default to True unless explicitly told otherwise.
+    purge_rules(args.group_id, args.region, args.profile, dry_run=args.dry_run)
+
+    if not args.dry_run:
+        print("\nPurge complete.")
+    else:
+        print("\nDry run finished. Use the same command without --dry-run to execute.")
+
+if __name__ == "__main__":
+    main()