ROS Iron Irwini - What's new -

see more details to https://docs.ros.org/en/rolling/Releases/Release-Iron-Irwini.html

Supported Platform

• Tier 1 platforms
  • Ubuntu 22.04 (amd64/aarch64)
  • Windows 10 (VS 2019) (amd64)
• Tier 2 platforms
  • RHEL 9 (amd64)
• Tier 3 platforms
  • macOS (amd64)
  • Debian Bullseye (amd64)

New Features

Service Introspection

This allows users to see the metadata and activities associated with the service, such as request, response. Optionally, the contents of the client/server requests/responses can also be introspected.
All of the information is published on a hidden topic generated from the name of the service.
So if the service is called /myservice, then the information will be published on /myservice/_service_event.

• This is opt-in that can be enabled via configure_introspection on service object.
• See more details REP 2012
• See Client Demo and Service Demo
• Additional features could leverage this feature next?
  • ros2 service echo
  • Playback recorded service via rosbag2
  • Introspection for ROS actions (rosbag2)

Improved Discovery

ROS Iron deprecates ROS_LOCALHOST_ONLY in favor of more granular options with following options.

• ROS_AUTOMATIC_DISCOVERY_RANGE
  • controls how far ROS nodes will try to discover each other.
  • valid options are SUBNET, LOCALHOST, OFF, and SYSTEM_DEFAULT.
  • SUBNET is the default, and for DDS based middlewares it means it will discover any node reachable via multicast. LOCALHOST means a node will only try to discover other nodes on the same machine. OFF means the node won't discover any other nodes, even on the same machine.

Improved Discovery

• ROS_STATIC_PEERS
  • is a semicolon (;) separated list of addresses that ROS should try to discover nodes on.
  • allows connecting to nodes on specific machines (as long as their discovery range is not set to OFF).
• Original Discussion
  • https://discourse.ros.org/t/proposed-changes-to-how-ros-performs-discovery-of-nodes/27640

Pre and Post parameter callback support

on_set parameter callback has been supported for many releases, but it does not allow the user application flexible parameter management with callback. The new parameter callbacks support modify the parameter list incoming, modify the state if necessary.

• pre set parameter callback, which can modify the list of parameters based on arbitrary criteria.
• set parameter callback, which cannot modify the list and should only accept or reject the parameters based on their type and value (already supported).
• post set parameter callback, which can make state changes based on parameters and is only called if the previous two callbacks are successful.
• See C++ Demo and Python Demo

Matched Events

Matched events can be generated when any publisher and subscription establishes or drops the connection between them. Users can provide each publisher and subscription with callback functions that are triggered by matched events and handle them in a way they see fit, similar to how messages received on a topic are handled.

• See more details for matched event design
• See C++ Demo and Python Demo

External configuration services of logger

It is now possible to configure node logger levels remotely via a service.

When the enable_logger_service option is enabled during node creation, the set_logger_levels and get_logger_levels services will be available.

Be advised that the enable_logger_service option is disabled by default, so the user needs to enable this option on node creation.

• See more details for External logging level configuration

EventExecutor

• New (*Experimental) Executor implementation uses event-driven callbacks rclcpp space.
• API compatible with other Executor implementation.
• see discourse discussion and design for more details.
• (Use caution as it will not be subject to the same API/ABI guarantees that the non-experimental code has.)

EventExecutor

• Built on top of DDS Listener API. (e.g on_data_available)
• avoid modifying and update waitset. (performance improvement)
• dedicated thread to manage timer. (high precision timer)
• thinner software stack, abstraction layer from user space to middleware.
• ordering event. (process events as they happened in order)

rclcpp

• Addition of a new paradigm for handling Node and LifecycleNode with NodeInterfaces
• default number of threads for MultiThreadedExecutor.
  • If the user doesn’t specify otherwise, the default number of threads for the multi-threaded executor will be set to the number of CPUs on the machine. If the underlying OS doesn’t support getting this information, it will be set to 2.

Minor Enhancements

rclpy

• Ability to wait for another node to join the graph (node.wait_for_node("fqdn"))
• AsyncParameterClient supported
• Subscription callbacks can now optionally get the message info
• Optional argument that hides assertions for messages class (performance improvement)
• default number of threads for MultiThreadedExecutor. (see rclcpp)

ros2param

• --timeout option to ros2 param when waiting node.
• ros2 param dump option --output-dir and --print has been removed.

ros2topic

• now keyword for builtin_interfaces.msg.Time that automatically generate the time.
• ros2 topic pub with --max-wait-time to wait the subscription.
• ros2 topic echo with --timeout to wait the publication.
• --lost-messages option ros2 topic echo has been removed.
• ros2 topic hz/bw/pub now respect use_sim_time.

rosbag2

• default bag file type to mcap
  • default bag file type has been changed into mcap from sqlite3.
  • mcap file format has many of the missing features from the sqlite3 file format, and should also be more performant.
  • The old sqlite3 file format is still available and can be selected by the user for writing if desired.