QoS Configuration

KOMPASS wrapper for ROS2 QoS (Quality of Service) configuration.

class QoSConfig

history: int

Configuration of samples to store (qos.HistoryPolicy)

• Values:
  KEEP_LAST: only store up to N samples, configurable via the queue depth option.
  KEEP_ALL: store all samples, subject to the configured resource limits of the underlying middleware.

• Default: qos.HistoryPolicy.KEEP_LAST

queue_size: int

Only honored if the “history” policy was set to “KEEP_LAST”<br/>

• Values: in [5, 100]

• Default: 10

reliability: int

Samples deliverance guarantee (qos.ReliabilityPolicy)

• Values:
  BEST_EFFORT: attempt to deliver samples, but may lose them if the network is not robust
  RELIABLE: guarantee that samples are delivered, may retry multiple time
  

• Default: qos.ReliabilityPolicy.RELIABLE

durability: int

Controls whether or not, and how, published DDS samples are stored (qos.DurabilityPolicy)<br/>

• Values:
  TRANSIENT_LOCAL:
  VOLATILE:
  UNKNOWN:
  SYSTEM_DEFAULT

• Default: qos.DurabilityPolicy.VOLATILE

Tip

Setup your QoSConfig and parse it into ROS2 by using ‘setup_qos’ method available in the Component

Usage Example

from kompass.config import QoSConfig, Topic
from rclpy import qos

qos_conf = QoSConfig(
    history=qos.HistoryPolicy.KEEP_LAST,
    queue_size=20,
    reliability=qos.ReliabilityPolicy.BEST_EFFORT,
    durability=qos.DurabilityPolicy.TRANSIENT_LOCAL
)
topic = Topic(name='/local_map', msg_type='OccupancyGrid', qos_profile=qos_conf)