S3: implement 'deletebucket' subcommand in xs3

src/XrdS3/app/xs3

@@ -58,6 +58,11 @@ def main():
     addbucket_parser.add_argument('bucketname', help='Bucket name')
     addbucket_parser.add_argument('bucketpath', help='Bucket path')
 
+    # Add the 'deletebucket' subcommand
+    deletebucket_parser = subparsers.add_parser('deletebucket', help='Delete an existing bucket')
+    deletebucket_parser.add_argument('username', help='Username')
+    deletebucket_parser.add_argument('bucketname', help='Bucket name')
+
     # Parse the arguments
     args = parser.parse_args()
 
@@ -70,6 +75,8 @@ def main():
         handle_deleteuser(args)
     elif args.subcommand == 'addbucket':
         handle_addbucket(args)
+    elif args.subcommand == 'deletebucket':
+        handle_deletebucket(args)
     else:
         parser.print_help()
 
@@ -354,13 +361,37 @@ def handle_addbucket(args):
         print(f"Error: Failed to read the config file '{config_file}'. {e}")
         return
 
+    # Check if the bucket file already exists
+    buckets_dir = os.path.join(base_path, 'buckets')
+    bucket_file = os.path.join(buckets_dir, bucketname)
+    if os.path.exists(bucket_file):
+        try:
+            owner_attr = os.getxattr(bucket_file, 'user.s3.owner')
+            path_attr = os.getxattr(bucket_file, 'user.s3.path')
+            owner = owner_attr.decode()
+            path = path_attr.decode()
+            print(f"Error: Bucket '{bucketname}' already exists. Owner: {owner}, Path: {path}")
+        except OSError as e:
+            print(f"Error: Failed to retrieve extended attributes from bucket file '{bucket_file}'. {e}")
+        return
+
     # Check if the user directory exists
     users_dir = os.path.join(base_path, 'users')
     user_dir = os.path.join(users_dir, username)
     if not os.path.exists(user_dir):
         print("Error: User does not exist - use 'adduser' first.")
         return
 
+    # Create an empty file under the users directory with the username
+    user_bucket_file = os.path.join(user_dir, bucketname)
+    if not os.path.exists(user_bucket_file):
+        try:
+            with open(user_bucket_file, 'w') as f:
+                f.write('')
+            print(f"Info: Empty file '{user_bucket_file}' created successfully under users directory.")
+        except OSError as e:
+            print(f"Error: Failed to create empty file '{user_bucket_file}' under users directory. {e}")
+
     # Create the bucket directory
     buckets_dir = os.path.join(base_path, 'buckets')
     bucket_file = os.path.join(buckets_dir, bucketname)
@@ -384,6 +415,69 @@ def handle_addbucket(args):
     except OSError as e:
         print(f"Error: Failed to set extended attributes on '{bucket_file}'. {e}")
 
+def handle_deletebucket(args):
+    username = args.username
+    bucketname = args.bucketname
+
+    # Determine the base path from the config file
+    config_dir = os.path.join(os.path.expanduser('~'), '.xs3')
+    config_file = os.path.join(config_dir, 'config')
+
+    if not os.path.exists(config_file):
+        print("Error: Configuration file does not exist. Please run 'config' subcommand first.")
+        return
+
+    try:
+        with open(config_file, 'r') as f:
+            config_data = json.load(f)
+        base_path = config_data.get('base_path')
+        if not base_path:
+            print("Error: Base path is not configured properly.")
+            return
+    except (IOError, json.JSONDecodeError) as e:
+        print(f"Error: Failed to read the config file '{config_file}'. {e}")
+        return
+
+    # Check if the user directory exists
+    users_dir = os.path.join(base_path, 'users')
+    user_dir = os.path.join(users_dir, username)
+    if not os.path.exists(user_dir):
+        print("Error: User does not exist - use adduser first.")
+        return
+
+    # Check if the bucket file exists
+    buckets_dir = os.path.join(base_path, 'buckets')
+    bucket_file = os.path.join(buckets_dir, bucketname)
+    if not os.path.exists(bucket_file):
+        print(f"Error: Bucket '{bucketname}' does not exist.")
+        return
+
+    # Check if the user is the owner of the bucket
+    try:
+        owner_attr = os.getxattr(bucket_file, 'user.s3.owner')
+        if owner_attr.decode() != username:
+            print("Error: User is not the owner of the given bucket.")
+            return
+    except OSError as e:
+        print(f"Error: Failed to retrieve extended attribute from bucket file '{bucket_file}'. {e}")
+        return
+
+    # Delete the bucket file
+    try:
+        os.remove(bucket_file)
+        print(f"Info: Bucket file '{bucket_file}' deleted successfully.")
+    except OSError as e:
+        print(f"Error: Failed to delete bucket file '{bucket_file}'. {e}")
+
+    # Delete the empty file under the users directory with the bucket name
+    user_bucket_file = os.path.join(user_dir, bucketname)
+    if os.path.exists(user_bucket_file):
+        try:
+            os.remove(user_bucket_file)
+            print(f"Info: Empty file '{user_bucket_file}' deleted successfully from users directory.")
+        except OSError as e:
+            print(f"Error: Failed to delete empty file '{user_bucket_file}' from users directory. {e}")
+
 
 if __name__ == '__main__':
     main()