1.2. Example of usage¶
This example will serve as a hands-on tutorial, aimed at introducing some of the key concepts and features that
eProsima DDS Record & Replay replay application (DDS Replayer or ddsreplayer
) has to offer.
1.2.1. Prerequisites¶
It is required to have eProsima DDS Record & Replay previously installed using one of the following installation methods:
Additionally, ShapesDemo is required to publish and subscribe shapes of different colors and sizes. Install it by following any of the methods described in the given links:
This is a follow-up tutorial, and assumes that DDS Recorder Example of usage has already been completed.
1.2.2. Start ShapesDemo¶
Let us launch a ShapesDemo instance and create a subscription in the Square
topic with default settings.
1.2.3. Replayer configuration¶
The only configuration option required by a DDS Replayer is the path to an input MCAP file, which can be provided both as a CLI argument or via YAML configuration.
By default, all messages stored in the provided input file are played back in DDS Domain 0
, starting at the very moment the application is launched.
It is also 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 DDS Replayer.
1.2.4. Replayer execution¶
Launching a DDS Replayer instance is as easy as executing the following command:
ddsreplayer -i output_YYYY-MM-DD-DD_hh-mm-ss.mcap
In order to know all the possible arguments supported by this tool, use the command:
ddsreplayer --help

Execution will end once every message found in the given input file is played back, although it can also be terminated with Ctrl+C
at any point.
1.2.5. Next Steps¶
Feel free to experiment with the many configuration options available for a DDS Replayer instance.
For example, you may try to modify the playback rate, block/allow the Square
topic in the middle of execution, or set a different topic QoS configuration via the builtin-topics list.