How to Create a ROS Package

ros-package

In this tutorial, we’ll learn how to create a ROS package. Software in ROS is organized into packages. Each package might contain a mixture of code (e.g. ROS nodes), data, libraries, images, documentation, etc. Here is the official ROS tutorial on how to create a ROS package. I will walk you through this process below.

Directions

Here is the syntax for creating a ROS package. Do not run this piece of code.

catkin_create_pkg <package_name> [depend1] [depend2] [depend3]

Now, open a new terminal window, and move to the source directory of the workspace you created. If you don’t already have a workspace set up, check out this tutorial.

cd ~/catkin_ws/src

Create a ROS package named ‘hello_world’. This package will have three dependencies (i.e. libraries the package depends on in order for the code inside the package to run properly): roscpp (the ROS library for C++), rospy (the ROS library for Python), and std_msgs (common data types that have been predefined in ROS … “standard messages”).

catkin_create_pkg hello_world std_msgs rospy roscpp
6-create-a-package

Type dir , and you will see that we now have a package named hello_world inside the source folder of the workspace. 

Change to the hello_world directory.

cd hello_world

Type:

dir
7-inside-src-folder

You can see that we have four files:

CMakeLists.txt: This text file contains the commands to compile the programs that you write in ROS. It also has the commands to convert your source code and other files into an executable (i.e. the code that your computer can run).

include: Contains package header files. You might remember when we wrote header files in the C++ tutorial…well this folder is where your header files would be stored.

src: This folder will contain the C++ source code. If you are doing a project in Python, you can create a new folder named scripts that will contain Python code. To create this new folder type:

mkdir scripts
8-make-directory-scripts

package.xml: This is an Extensible Markup Language (XML) file. An XML file is a text file written in a language (called XML) that is easy to read by both humans and computers. An XML file does not do anything other than store information in a structured way. 

Our package.xml file contains information about the hello_world package. You can see what is inside it by typing:

gedit package.xml
9-package-xml-file

That’s it! You’re all done.