In this tutorial, I will show you how to store your ROS 2 project in a repository on GitHub.
Follow along with me click by click, keystroke by keystroke.
In case you’re not familiar with GitHub, GitHub is an online platform specifically designed for software development. It offers several key functionalities:
- Version control: This allows you to track changes made to code over time. Think of it like a time machine for your code, letting you revert to previous versions if necessary.
- Code storage: GitHub acts as a secure and centralized location to store and manage code projects. Think of it like cloud storage specifically for your code.
- Collaboration: Teams can work together on projects by sharing code, discussing changes, and merging different contributions seamlessly.
- Open-source contribution: GitHub is a hub for open-source projects, where developers can publicly share their code, contribute to existing projects, and learn from others.
Prerequisites
- You have created a ROS 2 package inside a workspace.
- I have created a ROS 2 workspace that is at this path /home/ubuntu/ros2_ws/.
My package is called ros2_fundamentals_examples and is at this path: /home/ubuntu/ros2_ws/src/ros2_fundamentals_examples/
You can see the complete repository here on GitHub.
Install Git
The first thing you need to do is install Git. Open a new terminal window, and type:
sudo apt-get updatesudo apt-get install git -yCheck the git version you have.
git --versionConfigure Git
Configure your git username and email.
git config --global user.name "John Doe"git config --global user.email "johndoe@example.com"git config --global init.defaultBranch mainInitialize Git
Move to inside your project folder.
cd ~/ros2_ws/src/ros2_fundamentals_examples/Initialize the folder as a Git repository by running:
git initThis command allows you to start tracking changes to the files within that directory.
Add and Commit the Files to Your Local Repository
Add the files in your folder to the repository with the following command:
git add .Commit your staged files to your local repository with:
git commit -m "Initial commit"Create the Remote Repository on GitHub
Go to GitHub and log in.
Click on the “+” icon in the upper right corner and select “New repository.”
Name your repository.
Add a description (optional).
Choose whether the repository will be public or private.
Ignore the rest of the options.
Click “Create repository.”
Link the Local Repository to the Remote Repository
After creating your repository on GitHub, you’ll get a URL for that repository that looks like this: “https://github.com/…./ros2_fundamentals.git”
Go back to a terminal window, and link your local repository to GitHub with this command:
cd ~/ros2_ws/src/ros2_fundamentals_examples/git remote add origin <repository-URL>Now log in to your GitHub account again.
Creating a Fine-Grained Personal Access Token
A personal access token is like a special key that lets you access your GitHub account from other apps or scripts. It’s more secure than using your password because you can control what the token is allowed to do.
Here are the official steps, but we will walk through everything together now.
First, verify your email address, if it hasn’t been verified yet.
In the top-right corner of the GitHub page, click on your profile picture.
From the menu, click “Settings.”
In the left sidebar of the settings page, scroll down until you see “Developer settings.”
Click on “Developer settings.”
In the left sidebar, under Personal access tokens, click Fine-grained tokens.
Click Generate new token.
Follow the steps to authenticate your identity on GitHub.
Under Token name, enter a name for the token.
Under Resource owner, select a resource owner. The token will only be able to access resources owned by the selected resource owner.
Under Expiration, select an expiration for the token.
Optionally, under Description, add a note to describe the purpose of the token.
Under Repository access, select which repositories you want the token to access.
If you selected Only select repositories in the previous step, under the Selected repositories dropdown, select the repositories that you want the token to access. I will select the ros2_fundamentals_examples repository.
Under Permissions, select which permissions to grant the token. Depending on which resource owner and which repository access you specified, there are repository and account permissions. You should choose the minimal permissions necessary for your needs.
I will grant “Read and write” permissions to all of the resources. If “Read and write” is not available for a particular resource, select “Read-only”.
Click Generate token.
Copy the personal access token that you see, and save it somewhere safe.
Push Code to GitHub
Finally, push your code from your local repository (the folder on your computer) to GitHub (the remote folder) with:
cd ~/ros2_ws/src/ros2_fundamentals_examples/git push -u origin mainEnter your GitHub Username.
Then, when it asks for your password, enter the personal access token you created in the previous section.
With this command we have created a two-way connection between your local code and GitHub.
The git push -u origin main command uploads your local code to GitHub while simultaneously setting up a tracking relationship between your local and remote branches.
The -u (or –set-upstream) flag tells Git to remember this connection, so in the future you can simply use git push or git pull without needing to specify where to push to or pull from.
origin refers to your GitHub repository, and main is the name of your branch.
Now if you go back to GitHub, you can see your repository.
Git Command Overview
When you make changes to your code on your computer, and want to get these code changes saved to GitHub, here is how you do it:
git add . This command picks up all your new code changes and gets them ready to be saved. It’s like gathering up all your files into a neat pile.
git commit -m "description of changes" This command saves these changes on your computer with a message explaining what you did. It’s like putting that pile of files into a labeled folder.
git push This command sends all your saved changes to GitHub. Think of it like uploading your folder to the cloud so others can see it and you have a backup.
You’ll repeat these three steps each time you want to update your code on GitHub.
And if you’re working with other people, you should always download their changes first using git fetch, git status, and then git pull (one command right after the other) before you start working.
git fetch checks GitHub to see what changes exist – it’s like looking at a list of updates available but not downloading them yet. It tells you what’s different between your code and GitHub’s code.
git status shows you exactly what’s different between your local code and the code on GitHub after you’ve fetched. It’s like comparing your version with GitHub’s version to see what’s changed.
git pull actually downloads those changes from GitHub to your computer, bringing your local code up to date. It’s like clicking “download” on those updates you found with fetch and status.
These three commands help you safely check for and get any updates before you start working, which helps avoid conflicts with other people’s code changes.
Remove the Need to Use a Username and Password
If you want to not have to use a username and password every time you run “git push”, you can use SSH keys. This page has the official instructions on how to do that.
Here is the process…
Generate an SSH key pair (if you don’t already have one) by running:
ssh-keygen -t ed25519 -C "your_email@example.com"When you get prompted for a password or saving location, just keep pressing Enter, which will accept the default.
Start the ssh-agent in the background.
eval "$(ssh-agent -s)"Add your SSH private key to the ssh-agent:
ssh-add ~/.ssh/id_ed25519Add the SSH public key to your Git server.
cat ~/.ssh/id_ed25519.pubCopy the entire result to your clipboard by highlighting everything and copying it.
Go to your GitHub account “Settings” by clicking your profile icon in the upper right of the website.
Look for “SSH and GPG keys”.
Add a New SSH key.
Paste the copied key as an “Authentication Key”. Also add a title (you can make it whatever you want).
Click Add SSH key.
Go back to the main page of your repository on GitHub.
Find the SSH URL by clicking the green button labeled “Code”.
Copy the SSH URL that is in there.
Switch your repository’s remote URL to SSH by going to your Ubuntu Linux terminal window, and moving to the directory of your repository.
cd <path to your your local repository>For example:
cd ~/ros2_ws/src/ros2_fundamentals_examples/git remote set-url origin git@github.com:username/repository.gitTo confirm everything is setup properly, type:
git pullIf you get asked about the authenticity of the host, just type yes and press Enter.
That’s it.
Using SSH keys is a more secure and convenient method for machines where you regularly push changes, as it doesn’t require entering your credentials after the initial setup.
Keep building!