Continuous Deployment

This project is an example of continuous deployment of a Symfony 4 project.

• Symfony 4
• PHP 7.2 and Apache (mod_php)
• MYSQL 5.7
• Doctrine ORM

The Symfony project is slightly modified with Controller As A Service, Zend Template Renderer, PSR-7 requests and responses, PSR-15 request handlers.

Local docker environment

The local docker environment uses the code as a volume, and has a mysql and a minio server for persistance.

First deployment

We will first deploy the project locally on the local machine using git.

We are assuming the project is currently properly versioned. We will need to create a repository that will act as a remote for us, then edit its hooks to trigger actions when receiving code, and finally set a symlink to handle the webserver configuration.

Create the folder structure

Assuming ./ as your current directory, empty for now.

Clone this repository in the ./project folder (git clone git@github.com:tdutrion/continuous-deployment.git project).

Then create an empty repository using mkdir remote && cd remote && git init --bare.

Get back to your initial directory (cd ..).

Finally, let's create our deployment folders (mkdir -p deployment/{blue,green}).

Configure git

Copy the post-receive hook sample and edit it:

touch remote/hooks/post-receive && chmod +x remote/hooks/post-receive

#!/bin/bash

while read oldrev newrev ref
do
    if [[ $ref =~ .*/master$ ]];
    then
        cd ..
        echo "Master ref received.  Deploying master branch to production..."
        deployment_dir=$(readlink -- "deployment/current")
        echo "Currently deployed: $deployment_dir"
        temp_dir="/tmp/$(uuidgen)";
        mkdir $temp_dir;
        if [ "$deployment_dir" != "./blue/public" ]; then
            echo "building for blue";
            if [ -d $temp_dir ]; then
                rm -r $temp_dir;
            fi
            git clone remote $temp_dir;
            APP_ENV=prod composer install --working-dir=$temp_dir --prefer-dist --no-dev --no-suggest --optimize-autoloader --classmap-authoritative;

            # Check whether everything went as planned.

            if [ -d deployment/blue ]; then
                rm -r deployment/blue;
            fi
            cp -R $temp_dir deployment/blue
            if [ -L deployment/current ]; then
                rm deployment/current;
            fi
            ln -s ./blue/public deployment/current;
        else
            echo "building for green";
            if [ -d $temp_dir ]; then
                rm -r $temp_dir;
            fi
            git clone remote $temp_dir;
            APP_ENV=prod composer install --working-dir=$temp_dir --prefer-dist --no-dev --no-suggest --optimize-autoloader --classmap-authoritative;

            # Check whether everything went as planned.

            if [ -d deployment/green ]; then
                rm -r deployment/green;
            fi
            cp -R $temp_dir deployment/green
            if [ -L deployment/current ]; then
                rm deployment/current;
            fi
            ln -s ./green/public deployment/current;
        fi
        echo "SetEnv APP_ENV prod" > deployment/current/.htaccess;
        rm -rf $temp_dir;
    else
        echo "Ref $ref successfully received.  Doing nothing: only the master branch may be deployed on this server."
    fi
done

This script can obviously be optimised but you get the idea.

Make sure it is executable (chmod +x remote/hooks/post-receive).

Then make sure we know which one of green or blue is the current deployment. Because we're on a single server, we will use a symlink. The same concept could be applied using DNS resolution or a reverse proxy configuration.

ln -s ./blue/public deployment/current

After you need to go in project folder

cd ./project

Now you can change the remote of project

git remote rm origin
git remote add origin ../remote
git push origin master

Last thing we need to do here is to set a webserver with a document root pointing on the public directory of the symlink.

mkdir env
touch env/Dockerfile

Add the following content to the Dockerfile:

FROM php:7.2-apache

RUN docker-php-ext-install pdo pdo_mysql \
 && a2enmod rewrite \
 && sed -i 's!/var/www/html!/var/www/html/deployment/current!g' /etc/apache2/sites-available/*.conf

WORKDIR /var/www/html

docker build -t continuous-deployment/server-demo env
docker run --rm -v $(pwd):/var/www/html:cached -p 80:80 continuous-deployment/server-demo

You need to be careful that port 80 is not used already, or change it in the command.

You can go on http://127.0.0.1 and you should see one page with Hello World

Now you can try to edit content of message

vim project/src/Action/Home.php

Now you can do the same things what you did before, and you will see the page change without downtime (you may need to clear the webbrowser http cache)

git status
git add .
git commit -m "second commit"
git push origin master

Build Docker

Launch a docker registry:

docker run -d -p 6000:5000 --name registry registry:2

Then try to push your existing image:

docker tag continuous-deployment/server-demo localhost:6000/continuous-deployment/server-demo
docker push localhost:6000/continuous-deployment/server-demo

When you then try to run it, an error will occur as we haven't added the code yet. Add a new Dockerfile in ./Dockerfile:

FROM php:7.2-apache

RUN docker-php-ext-install pdo pdo_mysql \
 && a2enmod rewrite \
 && sed -i 's!/var/www/html!/var/www/html/deployment/current!g' /etc/apache2/sites-available/*.conf

ADD . /var/www/html

WORKDIR /var/www/html

In order not to add the whole context, add a ./.dockerignore:

project/
remote/
env/

docker build -t continuous-deployment/server-demo .
docker run --rm -p 80:80 continuous-deployment/server-demo