15.12. How to use eProsima DDS Record and Replay

eProsima DDS Record and Replay is an end-user software application that efficiently saves DDS data published into a DDS environment in a MCAP format database. Thus, the exact playback of the recorded network events is possible as the data is linked to the timestamp at which the original data was published. This facilitates the debugging of DDS networks.

15.12.1. Getting started

eProsima DDS Record & Replay includes the following tools:

DDS Recorder tool: This tool’s primary function is to store data in an MCAP database, including the publication timestamp, serialized data, and its format. The output MCAP file can be read by any compatible tool, as it contains all necessary information for data reproduction.
DDS Remote Controller tool: This application enables remote control of the recording tool, allowing a user to start, stop, or pause data recording from another device.
DDS Replay tool: This application allows replay of DDS traffic recorded with a DDS Recorder. Users can select messages to replay by setting a time range or by blocking/whitelisting specific topics. They can also adjust the playback rate and use different topic QoS settings from the original recording.

15.12.1.1. Prerequisites

eProsima DDS Record and Replay depends on eProsima Fast DDS library and certain Debian packages. For further information, please refer to the installation guide.

Furthermore, the example provided in this section requires ShapesDemo to publish and subscribe shapes of different colors and sizes.

15.12.2. Example of usage: Recording Application

This example will serve as a hands-on tutorial, aimed at introducing some of the key concepts and features that eProsima DDS Record & Replay recording application offers.

15.12.2.1. Start ShapesDemo

Let us launch a ShapesDemo instance and start publishing in topics Square with default settings.

../../../_images/recorder_shapesdemo_publisher.png

15.12.2.2. Recorder configuration

ddsrecorder runs with default configuration settings. This default configuration records all messages of all DDS Topics found in DDS Domain 0 in the output_YYYY-MM-DD-DD_hh-mm-ss.mcap file.

Additionally, it is possible to change the default configuration parameters by means of a YAML configuration file.

Note

Please refer to Configuration for more information on how to configure a ddsrecorder.

15.12.2.3. Recorder execution

To start recording, execute the following command:

ddsrecorder

In order to know all the possible arguments supported by this tool, use the command:

ddsrecorder --help

Let us launch a ShapesDemo instance and start publishing in topics Square with default settings.

../../../_images/recorder_shapesdemo_exec.png

Stop the recorder with Ctrl+C and check that the MCAP file exists.

15.13. Next Steps

Once having finished a recording session, it is possible to play it back by using DDS Replay tool, as shown in this tutorial.

For further information, please refer to the eProsima DDS Record and Replay documentation.