This package is built and tested with ROS2 galactic.

This package adds verb extensions to the ros2bag cli.

You can check detailed usage information with ros2 bag $VERB --help.

Each command writes a new output bag on disk. If you need to chain multiple commands together, you can use ros2 bag process to process all messages in-memory and write only one output bag. To use it, create a config file that contains one line per command, with the same arguments as the cli interface.

For example create a file named process.config containing those lines:

cut --duration 10
extract -t /image_rect
restamp

and run ros2 bag process -c process.config in.bag -o out.bag to crop to the first 10 seconds, keep only the /image_rect topic and restamp the remaining messages in one go.

The verbs are built on top of utilities in rosbag2_tools.

You can iterate message data using BagView.

from rosbag2_tools.bag_view import BagView
reader = SequentialReader()
storage_options = StorageOptions(uri='test/range.bag', storage_id='sqlite3')
converter_options = ConverterOptions(
    input_serialization_format='cdr',
    output_serialization_format='cdr')
reader.open(storage_options, converter_options)
for _, range_msg, _ in BagView(reader):
    print('r', range_msg.range)

Or read topics as pandas data frames.

from rosbag2_tools.data_frame import read_data_frames
reader = SequentialReader()
storage_options = StorageOptions(uri='test/range.bag', storage_id='sqlite3')
converter_options = ConverterOptions(
    input_serialization_format='cdr',
    output_serialization_format='cdr')
reader.open(storage_options, converter_options)
dfs = read_data_frames(BagView(reader))
dfs['/range'].summary()

• Tools do not operate in-place, they all create new output bags, potentially doubling the required disk space
• The time filters used in the cut verb truncate timestamps to the microsecond, due to the precision loss of the pybind11-conversion of C++ chrono time objects to python3 datetime objects. Thus, filters are not sufficiently precise to handle timestamp deltas below 1000ns.