rosros | ROS core functionality

ROS core functionality

Functionality for creating and operating a ROS node.

Objects returned are standard rospy / rclpy API objects, patched with additional members for a unified interface conforming to ROS1 API.

Name	Description	Arguments
	Startup, spin and shutdown
`rosros.init_node`	initializes ROS and creates ROS node (and returns Node object in ROS2)	`name, args=None, namespace=None, anonymous=True, log_level=None, enable_rosout=True, multithreaded=True, reentrant=False`
`rosros.start_spin`	sets ROS node spinning forever in a background thread
`rosros.spin`	spins ROS node forever
`rosros.spin_once`	waits until timeout in ROS1; executes one ROS operation or waits until timeout in ROS2	`timeout=None`
`rosros.spin_until_future_complete`	spins ROS until future complete or timeout reached or ROS shut down	`future, timeout=None`
`rosros.ok`	returns whether ROS has been initialized and is not shut down
`rosros.on_shutdown`	registers function to be called on shutdown	`callback, args, *kwargs`
`rosros.shutdown`	shuts down live ROS node, if any	`reason=None`

	Parameters
`rosros.init_params`	sets all parameters on node from defaults dictionary, returns full parameters dictionary.	`defaults=None, **defaultkws`
	In ROS2, auto-declares unregistered parameters.
`rosros.has_param`	returns whether the parameter exists	`name`
`rosros.get_param`	returns parameter value from current ROS node	`name, default=None, autoset=True`
`rosros.get_param_names`	returns the names of all current ROS node parameters
`rosros.get_params`	returns the current ROS node parameters, by default as nested dictionary	`nested=True`
`rosros.set_param`	sets a parameter on the node.	`name, value, descriptor=None`
	In ROS2, parameter will be auto-declared if unknown so far.
`rosros.delete_param`	deletes parameter from the node	`name`

	Topics, services, timers and rates
`rosros.create_publisher`	returns a ROS publisher instance	`topic, cls_or_typename, latch=False, queue_size=0, **qosargs`
`rosros.create_subscriber`	returns a ROS subscriber instance	`topic, cls_or_typename, callback, callback_args=None, queue_size=0, raw=False, **qosargs`
`rosros.create_service`	returns a ROS service server instance, for providing a service	`service, cls_or_typename, callback, **qosargs`
`rosros.create_client`	returns a ROS service client instance, for invoking a service	`service, cls_or_typename, **qosargs`
`rosros.create_timer`	returns a ROS timer instance	`period, callback, oneshot=False, immediate=False`
`rosros.create_rate`	returns a ROS rate instance, for sleeping at a fixed rate	`frequency`
`rosros.destroy_entity`	closes the given publisher, subscriber, service client, service server, or timer instance	`item`
`rosros.AnyMsg`	`rospy.AnyMsg` in ROS1, stand-in class with equivalent functionality in ROS2
`sleep`	sleeps for the specified duration in ROS time	`duration`
`wait_for_publisher`	blocks until topic has at least one publisher	`topic, timeout=None, cls_or_typename=None`
`wait_for_subscriber`	blocks until topic has at least one subscriber	`topic, timeout=None, cls_or_typename=None`
`wait_for_service`	blocks until service is available	`service, timeout=None, cls_or_typename=None`

	ROS bags
`rosros.Bag`	ROS bag reader and writer;
	`rosbag.Bag` in ROS1 with some additional functionality;
	equivalent class in ROS2, using the ROS2 default SQLite format

	Information queries
`rosros.get_namespace`	returns ROS node namespace
`rosros.get_node_name`	returns ROS node full name with namespace
`rosros.get_nodes`	returns all ROS nodes, as `[node full name, ]`
`rosros.get_topics`	returns all available ROS topics, as `[(topic name, [type name, ]), ]`
`rosros.get_services`	returns all available ROS services, as `[(service name, [type name, ]), ]`
`rosros.remap_name`	returns the absolute remapped topic/service name if mapping exists	`name, namespace=None`
`rosros.resolve_name`	returns absolute remapped name, namespaced under current node if relative or private	`name, namespace=None`

	Miscellaneous
`rosros.get_logger`	returns `logging.Logger` for logging to ROS log handler;
	logger supports additional keywords `__once__, __throttle__, __throttle_identical__`
`rosros.get_ros_version`	returns ROS version information as a data dictionary
`rosros.get_rostime`	returns ROS time instance for current ROS clock time
`rosros.register_init`	informs `rosros` of ROS having been initialized outside of `init_node()`.	`node=None`
	Giving node as argument is mandatory in ROS2.

Patches in ROS1

Additional functionality patched onto rospy classes for convenience:

rospy.ServiceProxy.call_async(*args, **kwargs):
makes service call in a background thread, returns asyncio.Future-like response
rospy.ServiceProxy.wait_for_service(timeout=None, timeout_sec=None): waits for service to become available, returns True, or False on timeout
rospy.ServiceProxy.service_is_ready():
returns whether service is currently available
rospy.Subscriber:
callbacks are invoked with serialized message bytes if subscription was created with raw=True
rosbag.Bag.get_message_definition(msg_or_type):
returns ROS1 message type definition full text from bag
rosbag.Bag.get_message_class(typename, typehash=None):
returns ROS1 message class
rosbag.Bag.get_message_type_hash(msg_or_type):
returns ROS1 message type MD5 hash
rosbag.Bag.get_topic_info():
returns topic and message type metainfo as {(topic, typename, typehash): count}
rosbag.Bag.reindex_file(f):
reindexes bag file on disk; makes a temporary copy in file directory

Patches in ROS2

The following classes are patched with full conformity to their equivalents in ROS:

rclpy.client.Client
rclpy.publisher.Publisher
cclpy.service.Service
rclpy.subscription.Subscription
rclpy.duration.Duration
rclpy.time.Time
rclpy.timer.Rate
rclpy.timer.Timer

E.g. durations support +-*/ arithmetic, and publisher / subscriber provide .md5sum for message type hash.