Quality of Service

class rclpy.qos.DurabilityPolicy(value)

Enum for QoS Durability settings.

This enum matches the one defined in rmw/types.h

RMW_QOS_POLICY_DURABILITY_SYSTEM_DEFAULT = 0

RMW_QOS_POLICY_DURABILITY_TRANSIENT_LOCAL = 1

RMW_QOS_POLICY_DURABILITY_UNKNOWN = 3

RMW_QOS_POLICY_DURABILITY_VOLATILE = 2

SYSTEM_DEFAULT = 0

TRANSIENT_LOCAL = 1

UNKNOWN = 3

VOLATILE = 2

class rclpy.qos.HistoryPolicy(value)

Enum for QoS History settings.

This enum matches the one defined in rmw/types.h

KEEP_ALL = 2

KEEP_LAST = 1

RMW_QOS_POLICY_HISTORY_KEEP_ALL = 2

RMW_QOS_POLICY_HISTORY_KEEP_LAST = 1

RMW_QOS_POLICY_HISTORY_SYSTEM_DEFAULT = 0

RMW_QOS_POLICY_HISTORY_UNKNOWN = 3

SYSTEM_DEFAULT = 0

UNKNOWN = 3

exception rclpy.qos.InvalidQoSProfileException(*args)

Raised when constructing a QoSProfile with invalid arguments.

class rclpy.qos.LivelinessPolicy(value)

Enum for QoS Liveliness settings.

This enum matches the one defined in rmw/types.h

AUTOMATIC = 1

MANUAL_BY_TOPIC = 3

RMW_QOS_POLICY_DURABILITY_UNKNOWN = 4

RMW_QOS_POLICY_LIVELINESS_AUTOMATIC = 1

RMW_QOS_POLICY_LIVELINESS_MANUAL_BY_TOPIC = 3

RMW_QOS_POLICY_LIVELINESS_SYSTEM_DEFAULT = 0

SYSTEM_DEFAULT = 0

UNKNOWN = 4

rclpy.qos.QoSDurabilityPolicy

alias of rclpy.qos.DurabilityPolicy

rclpy.qos.QoSHistoryPolicy

alias of rclpy.qos.HistoryPolicy

rclpy.qos.QoSLivelinessPolicy

alias of rclpy.qos.LivelinessPolicy

class rclpy.qos.QoSPolicyEnum(value)

Base for QoS Policy enumerations.

Provides helper function to filter keys for utilities.

classmethod get_from_short_key(name)

Retrieve a policy type from a short name, case-insensitive.

property short_key

classmethod short_keys()

Return a list of shortened typing-friendly enum values.

class rclpy.qos.QoSPolicyKind(value)

Enum for types of QoS policies that a Publisher or Subscription can set.

This enum matches the one defined in rmw/incompatible_qos_events_statuses.h

AVOID_ROS_NAMESPACE_CONVENTIONS = 512

DEADLINE = 4

DEPTH = 128

DURABILITY = 2

HISTORY = 32

INVALID = 1

LIFESPAN = 64

LIVELINESS = 8

LIVELINESS_LEASE_DURATION = 256

RELIABILITY = 16

class rclpy.qos.QoSPresetProfiles(value)

An enumeration.

ACTION_STATUS_DEFAULT = <rclpy.qos.QoSProfile object>

Noted that the following are duplicated from QoSPolicyEnum.

Our supported version of Python3 (3.5) doesn’t have a fix that allows mixins on Enum.

PARAMETERS = <rclpy.qos.QoSProfile object>

PARAMETER_EVENTS = <rclpy.qos.QoSProfile object>

SENSOR_DATA = <rclpy.qos.QoSProfile object>

SERVICES_DEFAULT = <rclpy.qos.QoSProfile object>

SYSTEM_DEFAULT = <rclpy.qos.QoSProfile object>

UNKNOWN = <rclpy.qos.QoSProfile object>

classmethod get_from_short_key(name)

Retrieve a policy type from a short name, case-insensitive.

classmethod short_keys()

Return a list of shortened typing-friendly enum values.

class rclpy.qos.QoSProfile(**kwargs)

Define Quality of Service policies.

property avoid_ros_namespace_conventions

Get field ‘avoid_ros_namespace_conventions’.

Returns

avoid_ros_namespace_conventions attribute

Return type

bool

property deadline

Get field ‘deadline’.

Returns

deadline attribute.

Return type

Duration

property depth

Get field ‘depth’.

Returns

depth attribute

Return type

int

property durability

Get field ‘durability’.

Returns

durability attribute

Return type

QoSDurabilityPolicy

get_c_qos_profile()

property history

Get field ‘history’.

Returns

history attribute

Return type

QoSHistoryPolicy

property lifespan

Get field ‘lifespan’.

Returns

lifespan attribute

Return type

Duration

property liveliness

Get field ‘liveliness’.

Returns

liveliness attribute

Return type

QoSLivelinessPolicy

property liveliness_lease_duration

Get field ‘liveliness_lease_duration’.

Returns

liveliness_lease_duration attribute.

Return type

Duration

property reliability

Get field ‘reliability’.

Returns

reliability attribute

Return type

QoSReliabilityPolicy

rclpy.qos.QoSReliabilityPolicy

alias of rclpy.qos.ReliabilityPolicy

class rclpy.qos.ReliabilityPolicy(value)

Enum for QoS Reliability settings.

This enum matches the one defined in rmw/types.h

BEST_EFFORT = 2

RELIABLE = 1

RMW_QOS_POLICY_RELIABILITY_BEST_EFFORT = 2

RMW_QOS_POLICY_RELIABILITY_RELIABLE = 1

RMW_QOS_POLICY_RELIABILITY_SYSTEM_DEFAULT = 0

RMW_QOS_POLICY_RELIABILITY_UNKNOWN = 3

SYSTEM_DEFAULT = 0

UNKNOWN = 3

rclpy.qos.qos_check_compatible(publisher_qos, subscription_qos)

Check if two QoS profiles are compatible.

Two QoS profiles are compatible if a publisher and subscription using the QoS policies can communicate with each other.

If any policies have value “system default” or “unknown” then it is possible that compatibility cannot be determined. In this case, the value QoSCompatibility.WARNING is set as part of the returned structure.

rclpy.qos.qos_policy_name_from_kind(policy_kind)

Get QoS policy name from QoSPolicyKind enum.

rclpy.qos.qos_profile_action_status_default = <rclpy.qos.QoSProfile object>

For actions, using reliable reliability, transient-local durability.

rclpy.qos.qos_profile_parameter_events = <rclpy.qos.QoSProfile object>

For parameter change events. Currently same as the QoS profile for parameters.

rclpy.qos.qos_profile_parameters = <rclpy.qos.QoSProfile object>

For parameter communication. Similar to service QoS profile but with larger queue depth so that requests do not get lost.

rclpy.qos.qos_profile_sensor_data = <rclpy.qos.QoSProfile object>

For sensor data, using best effort reliability and small queue depth

rclpy.qos.qos_profile_services_default = <rclpy.qos.QoSProfile object>

For services, using reliable reliability and volatile durability

rclpy.qos.qos_profile_system_default = <rclpy.qos.QoSProfile object>

Uses the default QoS settings defined in the DDS vendor tool

rclpy.qos.qos_profile_unknown = <rclpy.qos.QoSProfile object>

Used for initialization. Should not be used as the actual QoS profile.