Gitlab CI is a built-in continuous integration tool from Gitlab, in this tutorial, we will explain how to setup auto-deploy for any kind of system
You know that feeling when you upload a fully working local environment and the moment you test it online it doesn't work? Chances are you've forgotten about a few important files.
This is where Gitlab CI/CD comes in, each push to Gitlab will trigger a deployment job so all changed files are always in sync with your production website.
How does Gitlab CI/CD work?
When pushing any code to your repository Gitlab will check if you've a .gitlab-ci.yml file in your root directory.
This file will define how Gitlab CI should interact with your project.
Gitlab CI is based on the Docker environment, this means you can make use of thousands of Docker images which are hosting on Docker Hub.
You define in the file which Docker image should be used and build your commands from there on.
First of all, here's an example of how I build my very basic Gitlab CI file.
image: php:7.2-apache stages: - tests - staging - production before_script: - ... stylecheck: stage: tests script: - ... to_staging: stage: staging script: - git push ssh://<username>@<server-ip>:<port>/~/<path-to-online-git-repo> HEAD:refs/heads/master to_production: stage: production ...
The Docker image chose here is php:7.2-apache, which is defined by the image type.
You can see the stages as steps, if the first step fails it won't go do the next one, which is good because if a test fails you don't want to actually deploy anything.
The before_script in the root will be executed on every job, in case you need run
composer install or
npm install for every job.
The jobs are here
to_production, each with their own stage defined. But ofcourse you can have multiple jobs per stage.
The auto-deployment feature
The deployment of different apps can be quite different, but one thing is always certain. You'll need to get your code onto your server somehow. This can be either done using FTP, SFTP or SSH.
Prepare your server
Preparing your server is half the work, most servers and even shared hosting services have git pre-installed. (If not contact your hosting provider)
To transfer the files easily from Gitlab to the server I use a bare repository which will wait for a push to transfer the new code to the right position.
cd ~ mkdir repos/<my-site>.git && cd repos/<my-site>.git git init --bare nano hooks/post-receive
You now created an bare repository in the
~/repos/<my-site>.git directory. Now with nano paste in the following code:
#!/bin/bash echo "Pushing code to working directory.." GIT_WORK_TREE=<absolute-path-to-directory> git checkout -f cd <absolute-path-to-directory> composer install #only needed using Symfony php bin/console doctrine:schema:update --force #only needed using Symfony
This file acts as a hook when pushing to your server. It will take the code sent from Gitlab and copy it to the defined directory.
In case you need the commands like
composer install on your server you can just add them like above.
To finish things, give execute rights to the hook
chmod +x hooks/post-receive
Already now you can use the post-receive hook by pushing directly from your local repository, this defeats the purpose of using Gitlab CI though since you're not running any tests before deploying.
Depending on if you're using FTP or SSH you'll need either a FTP password or SSH private key to continue.
Since we don't want to pass this valuable information as cleartext to our .gitlab-ci.yml file I add them to the Gitlab CI secret variables.
The secret variables can be found under your project. Settings -> CI/CD -> Secret variables
Add the variable SSH_PRIVATE_KEY and paste in your private ssh key
cat ~/.ssh/id_rsa. (You first need to generate ssh key, with
Setup .gitlab-ci.yml file.
Now that your server and Gitlab is ready it's time to setup the .gitlab-ci.yml for deployment!
Remember, we just need to push our code to the hook made on our server, that's it!
to_staging: before_script: - "which ssh-agent || ( apk --update add openssh-client )" - eval $(ssh-agent -s) - mkdir -p ~/.ssh && chmod 700 ~/.ssh && rm ~/.ssh/id_rsa && touch ~/.ssh/id_rsa - ssh-keyscan -t rsa <server-address> >> ~/.ssh/known_hosts - echo "$SSH_PRIVATE_KEY" >> ~/.ssh/id_rsa && chmod 400 ~/.ssh/id_rsa script: - git push <username>@<server-address>:~/repos/<my-site>.git HEAD:refs/heads/master
That's it! Let's explain a little.
- You push your code from your local repository to Gitlab
- Gitlab sees your .gitlab-ci.yml file and will check for syntax errors.
- It will loop the stages and it's jobs, so in this example the test jobs will be ran first.
- Once in the staging process, it will validate the ssh connection between Gitlab CI and the client by using it's
$SSH_PRIVATE_KEYdefined in the secret variables.
- Now that we can connect to the server, execute a push command to it using the current branch.
- The server will receive an incoming push command on it's hook and will copy all of the code to the correct directory.
- It may or may not execute
composer installdepending on what you've setup.
Pro tip: I suggest you use your own Docker image, you can easily install composer, npm and all other dependencies. This decrease the time needed to execute the commands.
If you have any questions, like always feel free to comment below!
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