I am going to keep GIT and GITHUB article as short as possible. I am just covering basic the concepts that we will need for our Django CI/CD project. I am NOT going to cover concepts such as branches, pull requests and rebase. Because I don't want to digress the subject and also Jenkins and Kubernetes will require a lot of writing as well.
GIT is a version control system that allows multiple software engineers to work on the same code. By using GIT, we can do the followings:
- Manage projects with Repositories
- Clone a project to work on a local copy
- Control and track changes with Staging and Committing
- Branch and Merge to allow for work on different parts and versions of a project
- Pull the latest version of the project to a local copy
- Push local updates to the main project
GitHub, on the other hand is a web-based hosting service for git repositories where software engineers can store and share their code.
GIT is installed on Linux by default. You can check your version by running the following command on your terminal.
git version
Configuring GIT:
We need to configure GIT with our GIT username and email. Because git embeds this information every commit we make.
git config --global user.name "yourGITusername"
git config --global user.email "youremailaddress"
You can also modify your git config by editing the git config file.
nano ~/.gitconfig
The command below display your current config
git config -l Before we can use git commands, we have to initialize a folder as Git Repository. You can either create a new folder and initialize it or you can initialize an existing folder. I will initialize my website folder. You need to run init command while you are in that folder.
SSH Access to GITHUB:
You can access and write data in repositories on GitHub.com using SSH (Secure Shell Protocol). When you connect via SSH, you authenticate using a private key file on your local machine.
Go ahead and create a github account if you don't have already and log in to your GitHub account. Then navigate to Settings > SSH and GPG Keys >
Click generating SSH Keys link> Here you will find the step for Generating a new SSH key.
Open Terminal on your computer and paste the text below, substituting in your GitHub email address.
ssh-keygen -t ed25519 -C "This email address is being protected from spambots. You need JavaScript enabled to view it. "
When you're prompted to "Enter a file in which to save the key", you can press Enter to accept the default file location.
With SSH keys, if someone gains access to your computer, the attacker can gain access to every system that uses that key. To add an extra layer of security, you can add a passphrase to your SSH key. Enter a passphrase when prompted.
Add your SSH private key to the ssh-agent to manage your keys. If you created your key with a different name, or if you are adding an existing key that has a different name, replace id_ed25519 in the command with the name of your private key file.
eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_ed25519
We generated an SSH key pair, we must add the public key to GitHub.com to enable SSH access for your account.
First run the following command to display the SSH public key. Copy all of its content to your clipboard.
cat ~/.ssh/id_ed25519.pub
On GitHub navigate to Settings > SSH and GPG Keys > New SSH Key and just paste SSH public key and click Add button
Finally we can test our SSH connection to GitHub.
ssh -T This email address is being protected from spambots. You need JavaScript enabled to view it.
Verify printed fingerprint matches GitHub's SSH key fingerprints and type yes and hit enter.
Creating Repository and First Push:
Log onto GitHub > Repositories > New button > Fill out the new repository form and > Create Repository.
Before we can push our files to the repository, we have to add remote repositories on our terminal
#To add a new remote, use the git remote add command in the directory your repository is stored at.
git remote add <remotename> https://github.com/yourusername/yourrepository.git
#To confirm your remote repository
git remote -v
Then I add all files and folders to the staging area by using "git add ." command except the files and folder which are declared in .gitignore file.
Then I commit with a message "first commit". I choose the branch main. Then push.
git add .
git commit -m "first commit"
git branch -M main
git push --set-upstream <remotename> main
If we refresh our repo on GitHub, we will see our files our pushed already.
PUSH
Initial configuration is done. From now on I can just use simple add, commit and push commands like below.
For example I created a file named test.txt Then I ran "git add ." command to add all files to the staging.
If I run "git status" command I can see the status of staging area.
git commit -m "your commit message"
git push
And test.txt is pushed to GitHub.
PULL
Go ahead and create a file on GitHub named test2.txt. Then just run the following command on your terminal to pull all the changes for GitHub.
git pull
Now I have same files on github and my local computer.
Personal Access Token:
When we install Jenkins in the upcoming articles, we will need to let Jenkins server to access our GitHub account. The easiest way for this is to create a Personal Access Token.
In your GitHub Account, navigate to "Settings > Developer Settings > Personal Access Tokens> Generate A New Token> Give it a name > Set its validation period and scope >
Copy Your Token to a Safe Place". We will use this token to authenticate Jenkins Server while working with GitHub.
Branch Info on Terminal:
One last thing that I want to add here is displaying current branch info on our terminal. On your terminal, run the command below
sudo nano ~/.bashrc
add this to the bottom of the file and save it
function parse_git_branch () {
git branch 2> /dev/null | sed -e '/^[^*]/d' -e 's/* \(.*\)/(\1)/'
}
RED="\[\033[01;31m\]"
YELLOW="\[\033[01;33m\]"
GREEN="\[\033[01;32m\]"
BLUE="\[\033[01;34m\]"
NO_COLOR="\[\033[00m\]"
# without host
PS1="$GREEN\u$NO_COLOR:$BLUE\w$YELLOW\$(parse_git_branch)$NO_COLOR\$ "
# with host
# PS1="$GREEN\u@\h$NO_COLOR:$BLUE\w$YELLOW\$(parse_git_branch)$NO_COLOR\$ "
When we change our directory to our local git repo (website folder in my case), it will display the current GIT branch
