Cannot play multiple compressed files

[dabonnie]

Description

When attempting to play back rosbag2 compressed data, with multiple files, the playback terminates with an error.

Expected Behavior

Multiple compressed bag files should be able to be played back.

Actual Behavior

After recording rosbag data with the command

ros2 bag record -a -b 134217728 --compression-mode file --compression-format zstd

and attempting to play back the resulting files (more than 1) with the command

ros2 bag play <my_bag_directory>

it appears the first bag file is decompressed and played, but when attempting to decompress the ensuing file the following error is printed to the console:

ERROR] [1581565911.633620497] [rosbag2_transport]: Failed to play: Bagfile is not opened 

To Reproduce

1. Record compressed data which results in multiple bag files
2. Attempt to play the recorded data
3. Console / log print error results in error [rosbag2_transport]: Failed to play: Bagfile is not opened

System (please complete the following information)

• OS: ubuntu 18.04
• ROS 2 Distro: master, building from source

[dabonnie]

This is a potential fix: #294

[emersonknapp]

Thanks for reporting this as an issue - makes it easier to track