ROS2 Python - Multi-threading Executor

Hard Python for ROS2 55% pass rate
#python#threading#executor#concurrent

Practice the ROS2 Python - Multi-threading Executor coding problem in Python for ROS2. Browser-based execution with automated grading — no local ROS install required. 55% of engineers pass this challenge.

Problem Statement

By default, ROS2 callbacks in Python run in a single thread (sequentially). Use a MultiThreadedExecutor to allow parallel execution of callbacks from multiple nodes.

Requirements

  • Create two nodes: node_a and node_b (these exact names)
  • Each node logs a message every 1 second:
    • node_a logs: "node_a is running"
    • node_b logs: "node_b is running"
  • Use MultiThreadedExecutor to spin both nodes concurrently
  • Both nodes must be added to the executor using executor.add_node()
  • Do not use rclpy.spin() — it blocks and prevents multi-node execution

Input/Output Format

Output: Console logs showing both nodes running simultaneously, e.g.:

[node_a]: node_a is running
[node_b]: node_b is running
[node_a]: node_a is running

⚠️ Common Pitfalls

  • Forgetting executor.add_node(node) — both nodes must be registered
  • Calling rclpy.spin(node) blocks the thread, preventing the second node from running
  • Using SingleThreadedExecutor — it doesn't allow true parallelism

📚 Helpful Resources

Frequently asked questions

What is the ROS2 Python - Multi-threading Executor practice problem?

It is a hands-on Python for ROS2 challenge on SimuCode where you implement and run ROS2 code in the browser with runtime-verified tests.

How do I practice ROS2 Python - Multi-threading Executor online?

Open this page, sign in, and solve the problem in the built-in IDE. Your solution is graded against real ROS2 execution checks.

What skills does ROS2 Python - Multi-threading Executor test?

This Hard problem focuses on python, threading, executor skills used in robotics interviews and production systems.