Class HeartbeatNodelet

Inheritance Relationships

Base Type

  • public cras::Nodelet

Class Documentation

class HeartbeatNodelet : public cras::Nodelet

Nodelet that republishes heartbeat of a topic with header.

ROS parameters:

  • ~queue_size (uint, default 10): Queue size for the subscriber and publisher.

  • ~lazy (bool, default False): Whether to shut down the subscriber when the publisher has no subscribers.

  • ~tcp_no_delay (bool, default False): If True, the TCP_NODELAY flag is set for the subscriber. This should decrease the latency of small messages, but might give suboptimal transmission speed for large messages.

Subscribed topics:

  • ~input (any type with header): The input messages. If lazy is true, it will only be subscribed when ~input/heartbeat has some subscribers. If you subscribe to a message type without header, the node should not crash, but it will discard all received messages and print an error message.

Published topics:

  • ~input/heartbeat (cras_msgs/Heartbeat): The heartbeat.

Command-line arguments: This nodelet (or node) can also be called in a way backwards compatible with topic_tools nodes. This means you can pass CLI arguments specifying the topic to subscribe.

  • rosrun cras_topic_tools heartbeat [TOPIC_IN]

    • TOPIC_IN: The topic to subscribe. It is resolved against parent namespace of the node(let) (as opposed to the ~input topic which is resolved against the private node(let) namespace). The heartbeat topic will be TOPIC_IN/heartbeat.

Protected Types

typedef LazySubscriber<cras_msgs::Heartbeat, const ros::MessageEvent<const topic_tools::ShapeShifter>&> SubscriberType

The lazy subscriber type.

Protected Functions

void onInit() override
virtual void processMessage(const ::ros::MessageEvent<const ::topic_tools::ShapeShifter> &event)

Process the received message.

Parameters:

event – [in] The message event containing the received message.

Protected Attributes

ros::Publisher pub

The publisher of heartbeat messages.

std::unique_ptr<SubscriberType> sub

The lazy subscriber.

cras::optional<bool> hasHeader = {cras::nullopt}

Whether the subscribed topic has a header field. This is filled on receipt of the first message.