ROS Package Library

1.6.1 · active · verified Tue Apr 14

rospkg is a standalone Python library for the ROS (Robot Operating System) package system. It provides utilities for querying information about ROS packages, stacks, and distributions, abstracting the underlying filesystem layout. The current version is 1.6.1, with releases occurring every few months to once a year, reflecting active but measured development.

Warnings

breaking rospkg is not API compatible with older `roslib` modules it replaced (e.g., `roslib.manifest`, `roslib.packages`). Direct migration from `roslib` APIs will require code changes.
Fix: Review REP 114 for details on API changes. Adapt code to use `rospkg.RosPack` and `rospkg.Manifest` classes directly, noting changes in method signatures and return types (e.g., `get_depends` now takes a single package argument and returns a list of dependencies).
gotcha The `rospkg.ResourceNotFound` exception is commonly encountered if the ROS environment is not properly sourced (e.g., `setup.bash` not run) or the requested package does not exist within the active ROS workspace or installed distribution.
Fix: Ensure that the ROS environment setup file (e.g., `source /opt/ros/<distro>/setup.bash` or `source ~/catkin_ws/devel/setup.bash`) is executed in the shell where the Python script is run. Verify the package name is correct and the package is indeed discoverable by ROS.
gotcha While `pip install rospkg` is standard, in a full ROS installation, `rospkg` is often installed as a system dependency via `apt` (e.g., `sudo apt-get install python3-rospkg`). Mixing `pip` and `apt` installations of `rospkg` or its dependencies can lead to conflicts and unexpected behavior, especially in complex ROS environments.
Fix: Prefer the package manager (e.g., `apt`) provided by your ROS distribution if you are working within a standard ROS setup. Use `pip` only if you are in a standalone Python environment or if explicitly instructed for a specific ROS development workflow, ensuring virtual environments are used to isolate dependencies.

Install

pip install rospkg Install latest version

Imports

RosPack
```
from rospkg import RosPack
```
ResourceNotFound
```
from rospkg.common import ResourceNotFound
```
ResourceNotFound is in rospkg.common, not directly under rospkg.

Quickstart

This quickstart demonstrates how to initialize `RosPack` to find the path of a ROS package (`rospy`), list its dependencies (`roscpp`), and check for the existence of a package. It includes error handling for `ResourceNotFound`.

import rospkg
import os

try:
    # Initialize RosPack to query ROS packages
    r = rospkg.RosPack()

    # Get the path to a package, e.g., 'rospy'
    rospy_path = r.get_path('rospy')
    print(f"Path to rospy package: {rospy_path}")

    # List direct dependencies of a package, e.g., 'roscpp'
    # Note: 'roscpp' is typically a C++ package, but rospkg can still find its dependencies
    try:
        roscpp_depends = r.get_depends('roscpp')
        print(f"Dependencies of roscpp: {roscpp_depends}")
    except rospkg.ResourceNotFound:
        print("roscpp package not found, cannot list dependencies. Is a ROS environment sourced?")

    # Check if a package exists
    if r.has_package('rospy'):
        print("rospy package exists.")

except rospkg.ResourceNotFound as e:
    print(f"Error: ROS resource not found: {e}. Ensure ROS environment is sourced correctly.")
except Exception as e:
    print(f"An unexpected error occurred: {e}")

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