RuntimeError: Database directory already exists (/home/max/my_bag), can't overwrite existing database

[Akumar201]

I have created a simple script to store data , but I am not sure why I am getting this error

RuntimeError: Database directory already exists (/home/max/my_bag), can't overwrite existing database

import rclpy
from rclpy.executors import ExternalShutdownException
from rclpy.node import Node
from rclpy.serialization import serialize_message
import rosbag2_py
from sensor_msgs.msg import CameraInfo  # Import CameraInfo

class SimpleBagRecorder(Node):

    def __init__(self):
        super().__init__('simple_bag_recorder')
        self.writer = rosbag2_py.SequentialWriter()

        # Set the bag file location to /home/max/my_bag and use the MCAP storage format.
        storage_options = rosbag2_py.StorageOptions(
            uri='/home/max/my_bag',
            storage_id='mcap')  # Use mcap storage identifier
        converter_options = rosbag2_py.ConverterOptions('', '')
        self.writer.open(storage_options, converter_options)

        # Define the topic metadata for the CameraInfo topic without using the id parameter
        topic_info = rosbag2_py.TopicMetadata(
            name='/cam_high/D405_high/color/camera_info',
            type='sensor_msgs/msg/CameraInfo',
            serialization_format='cdr')
        self.writer.create_topic(topic_info)

        # Subscribe to the CameraInfo topic
        self.subscription = self.create_subscription(
            CameraInfo,
            '/cam_high/D405_high/color/camera_info',
            self.topic_callback,
            10)
        self.subscription  # prevent unused variable warning

    def topic_callback(self, msg):
        self.writer.write(
            '/cam_high/D405_high/color/camera_info',
            serialize_message(msg),
            self.get_clock().now().nanoseconds)

def main(args=None):
    rclpy.init(args=args)
    try:
        sbr = SimpleBagRecorder()
        rclpy.spin(sbr)
    except KeyboardInterrupt:
        pass
    finally:
        rclpy.shutdown()

if __name__ == '__main__':
    main()

[christophebedard]

rosbag2 expects the directory (uri of StorageOptions) to not exist. You would have to delete the directory before trying to record again. Or you could append a timestamp to the directory name to make it unique, e.g. /home/max/my_bag_202502241500. This is what ros2 bag record does if you don't specify a directory: https://github.com/ros2/rosbag2?tab=readme-ov-file#recording-data.

[Akumar201]

The issue is even if I clean everything and try to re-run the code it complains about the same.

[MichaelOrlov]

@Akumar201

• Please refer to the relevant issue with a detailed explanation Allow writing files to an existing directory #1717

[christophebedard]

The issue is even if I clean everything and try to re-run the code it complains about the same.

You deleted /home/max/my_bag?

[Akumar201]

Yes, I deleted

[christophebedard]

If I run your script twice without deleting ~/my_bag, I do get this error:

Traceback (most recent call last):
  File "/home/christophe.bedard/ros2_ws/rosbag2_1921.py", line 53, in <module>
    main()
  File "/home/christophe.bedard/ros2_ws/rosbag2_1921.py", line 45, in main
    sbr = SimpleBagRecorder()
  File "/home/christophe.bedard/ros2_ws/rosbag2_1921.py", line 19, in __init__
    self.writer.open(storage_options, converter_options)
RuntimeError: Bag directory already exists (/home/christophe.bedard/my_bag), can't overwrite existing bag

It works fine for me if I delete ~/my_bag before re-running the script again.

Can you provide more information? Like which distro you're using.

[emersonknapp]

I suspect that you did not actually succeed in cleaning/deleting the directory. Can you please copy-paste the exact sequence of commands that you used, and the resulting output?

for example:

$ python3 my_script.py
$ rm -r /home/max/my_bag
$ python3 my_script.py
RuntimeError: Database directory already exists (/home/max/my_bag), can't overwrite existing database