ROS 2 tf2 transform listener and turtle-following node

Official ROS geometry tutorial node that spawns turtle2, looks up its transform relative to a target frame and publishes Twist velocity commands to follow that target. It is an installed ROS 2 console entrypoint with ROS graph effects, not a direct Python-file main or a verified robot controller.

ros2-tf2-listener | Record version: source-bb2c9f91a430216878a831f355f529761dadb8603e3e390ecf6ec9626fa4713f

Record JSON | Markdown | Pinned upstream source

Access

Read the pinned node, package declarations and setup registration before configuring the intended ROS graph. This source reference does not install or execute code.

For one verified inert file, use the installed CLI's inspect response fetch_source_args and append --project DIR --json. Source-file retrieval creates no environment and does not install or run the source.

Hub preparation adapter: false. Follow the upstream setup and invocation contract.

Source and license

Repository: https://github.com/ros/geometry_tutorials
Revision: 8e677416092ac97606a4a23256c815ba2fe762d4
Path: turtle_tf2_py/turtle_tf2_py/turtle_tf2_listener.py
Source SHA256: bb2c9f91a430216878a831f355f529761dadb8603e3e390ecf6ec9626fa4713f
Source bytes: 4419
Original authors: Open Source Robotics Foundation, Inc.
License: Apache-2.0
License scope: Selected listener source under its explicit Apache-2.0 header, copyright 2021 Open Source Robotics Foundation, Inc. Preserve attribution, license and applicable notices. The package also declares BSD for other material; this source review does not clear the full package, dependencies or physical-robot use.
License SHA256: not independently verified
Hub commit: 0442ed7b99d78a970e92780a16df793e65039370

Artifact

{
  "kind": "code",
  "format": "python"
}

Requirements

{
  "python": null,
  "packages": [
    "Compatible ROS 2 rclpy environment with the context-manager init API used by this source",
    "tf2_ros",
    "geometry_msgs",
    "turtlesim_msgs",
    "Installed turtle_tf2_py package exposing the reviewed console entrypoint"
  ],
  "hardware": [],
  "system": [
    "Configured ROS graph providing the relative spawn service and appropriate turtle1/turtle2 transforms",
    "Reviewed namespace, target_frame parameter and intended turtle2/cmd_vel subscribers"
  ],
  "notes": "The package is labeled version 0.7.0 at a Rolling-branch source pin; neither label establishes a tested ROS distribution, Python version or operating system. The node defaults target_frame to turtle1, requests turtle2 at x=4.0, y=2.0, theta=0.0 and, after spawning, queries a transform into turtle2 with rclpy.time.Time(). On a nominal one-second timer it publishes angular z from atan2 and linear x as 0.5 times translation distance. The period and gains are source settings, not measurements. Transform failures are logged and return without an explicit zero-velocity stop. No obstacle check or speed clamp is present. This node does not generate its required transforms, and a single source file is insufficient. ROS graph dependencies, shutdown behavior, hardware remappings and compatibility remain untested."
}

Invocation

{
  "entrypoint": "ros2 run turtle_tf2_py turtle_tf2_listener",
  "notes": "Installed ROS 2 console command backed by the pinned setup.py registration turtle_tf2_py.turtle_tf2_listener:main. The source defines main without a __main__ guard; direct python-file execution is not the declared node invocation. Starting the console entrypoint initializes rclpy, calls a spawn service and can publish velocity commands to the configured graph. No physical-controller compatibility or safe stopping is established. The Hub supplies inert source metadata with no preparation/execution adapter and ran no ROS node or simulator."
}

Explicit compatibility

[]

Missing environment fields remain unknown. Discovery labels do not establish robot compatibility.

Evidence

Level: source_reviewed; runtime verification: not_run.

Complete node read as inert text and Python AST parsed without import or execution. Source, license, package XML and setup bytes matched SHA-256, lengths and immutable-tree Git blob pins. Installed console registration and ROS graph effects were inspected; no ROS/Python/OS combination, controller, simulator or task result was tested.

Source review and contributor reports do not establish task completion. Preserve upstream attribution and licenses.