Module client

Register function to be called on shutdown. This function will be called before Node begins teardown.

Parameters:

• h (fn()) - Function with zero args to be called on shutdown.

Blocks until ROS node is shutdown. Yields activity to other threads.

Raises:

• ROSInitException - if node is not in a properly initialized state

Helper function for using sys.argv is ROS client libraries.

Returns: [str]

copy of sys.argv with ROS remapping arguments removed

Register client node with the master under the specified name. This MUST be called from the main Python thread unless disable_signals is set to True. Duplicate calls to init_node are only allowed if the arguments are identical as the side-effects of this method are not reversible.

Parameters:

• name (str) - Node's name. This parameter must be a base name, meaning that it cannot contain namespaces (i.e. '/')
• argv ([str]) - Command line arguments to this program, including remapping arguments (default: sys.argv). If you provide argv to init_node(), any previously created rospy data structure (Publisher, Subscriber, Service) will have invalid mappings. It is important that you call init_node() first if you wish to provide your own argv.
• anonymous (bool) - if True, a name will be auto-generated for the node using name as the base. This is useful when you wish to have multiple instances of the same node and don't care about their actual names (e.g. tools, guis). name will be used as the stem of the auto-generated name. NOTE: you cannot remap the name of an anonymous node.
• log_level (int) - log level for sending message to /rosout and log file, which is INFO by default. For convenience, you may use rospy.DEBUG, rospy.INFO, rospy.ERROR, rospy.WARN, rospy.FATAL
• disable_signals (bool) - If True, rospy will not register its own signal handlers. You must set this flag if (a) you are unable to call init_node from the main thread and/or you are using rospy in an environment where you need to control your own signal handling (e.g. WX). If you set this to True, you should call rospy.signal_shutdown(reason) to initiate clean shutdown.

  NOTE: disable_signals is overridden to True if roslib.is_interactive() is True.

• disable_rostime (bool) - for rostests only, suppresses automatic subscription to rostime
• disable_rosout - suppress auto-publication of rosout

Raises:

• ROSInitException - if initialization/registration fails
• ValueError - if parameters are invalid (e.g. name contains a namespace or is otherwise illegal)

Get a remote handle to the ROS Master. This method can be called independent of running a ROS node, though the ROS_MASTER_URI must be declared in the environment.

Returns: rospy.MasterProxy

ROS Master remote object

Raises:

• Exception - if server cannot be located or system cannot be initialized

Retrieve list of topics that the master is reporting as being published.

Returns: [[str, str]]

List of topic names and types: [[topic1, type1]...[topicN, typeN]]

Receive one message from topic.

This will create a new subscription to the topic, receive one message, then unsubscribe.

Parameters:

• topic (str) - name of topic
• topic_type (rospy.Message class) - topic type
• timeout (double) - timeout time in seconds

Returns: rospy.Message

Message

Raises:

• ROSException - if specified timeout is exceeded
• ROSInterruptException - if shutdown interrupts wait

Retrieve a parameter from the param server

Parameters:

• default (any) - (optional) default value to return if key is not set

Returns: XmlRpcLegalValue

parameter value

Raises:

• ROSException - if parameter server reports an error
• KeyError - if value not set and default is not given

Retrieve list of parameter names.

Returns: [str]

parameter names

Raises:

• ROSException - if parameter server reports an error

Set a parameter on the param server

Parameters:

• param_name (str) - parameter name
• param_value (XmlRpcLegalValue) - parameter value

Raises:

• ROSException - if parameter server reports an error

Search for a parameter on the param server

Parameters:

• param_name (str) - parameter name

Returns: str

key of matching parameter or None if no matching parameter.

Raises:

• ROSException - if parameter server reports an error

Delete a parameter on the param server

Parameters:

• param_name (str) - parameter name

Raises:

• KeyError - if parameter is not set
• ROSException - if parameter server reports an error

Test if parameter exists on the param server

Parameters:

• param_name (str) - parameter name

Raises:

• ROSException - if parameter server reports an error

sleep for the specified duration in ROS time. If duration is negative, sleep immediately returns.

Parameters:

• duration (float or Duration) - seconds (or rospy.Duration) to sleep

Raises:

• ROSInterruptException - if ROS time is set backwards or if ROS shutdown occurs before sleep completes