First application

Task Overview

In this tutorial, we will build an image of simple PHP Symfony application. It includes the following steps:

1. Installing required software and dependencies: php, curl, php-sqlite for the application, php-xml and php-zip for the composer.
2. Setting up an app user and group for the web server.
3. Installing the composer from a phar file, which is first downloaded with curl.
4. Installing other project dependencies with the composer.
5. Adding the application code to the /app directory of the resulting image. This directory and all files in it should belong to app:app.
6. Setting up the IP address that the web server will listen to. This is done with a setting in /apt/start.sh, which will run when the container starts.
7. Making custom setup actions. As an illustration for the setup stage, we will write current date to version.txt.

Also, we will check that the application works and push the image in a Docker registry.

Requirements

• Minimal knowledge of Docker and Dockerfile instructions.
• Installed werf dependencies on the host system.
• Installed multiwerf on the host system.

Select werf version

This command should be run prior running any werf command in your shell session:

. $(multiwerf use 1.1 stable --as-file)

Step 1: Add a config

To implement these steps and requirements with werf we will add a special file called werf.yaml to the application’s source code.

1. Clone the Symfony Demo Application repository to get the source code:

   git clone https://github.com/symfony/symfony-demo.git
   cd symfony-demo
   

2. In the project root directory create a werf.yaml with the following contents:

   Ansible Shell

   project: symfony-demo
   configVersion: 1
   ---
   
   image: ~
   from: ubuntu:16.04
   docker:
     WORKDIR: /app
     # Non-root user
     USER: app
     EXPOSE: "80"
     ENV:
       LC_ALL: en_US.UTF-8
   ansible:
     beforeInstall:
     - name: "Install additional packages"
       apt:
         state: present
         update_cache: yes
         pkg:
         - locales
         - ca-certificates
     - name: "Generate en_US.UTF-8 default locale"
       locale_gen:
         name: en_US.UTF-8
         state: present
     - name: "Create non-root group for the main application"
       group:
         name: app
         state: present
         gid: 242
     - name: "Create non-root user for the main application"
       user:
         name: app
         comment: "Create non-root user for the main application"
         uid: 242
         group: app
         shell: /bin/bash
         home: /app
     - name: Add repository key
       apt_key:
         keyserver: keyserver.ubuntu.com
         id: E5267A6C
     - name: "Add PHP apt repository"
       apt_repository:
         repo: 'deb http://ppa.launchpad.net/ondrej/php/ubuntu xenial main'
         update_cache: yes
     - name: "Install PHP and modules"
       apt:
         name: "{{`{{packages}}`}}"
         state: present
         update_cache: yes
       vars:
         packages:
         - php7.2
         - php7.2-sqlite3
         - php7.2-xml
         - php7.2-zip
         - php7.2-mbstring
         - php7.2-intl
     - name: Install composer
       get_url:
         url: https://getcomposer.org/download/1.6.5/composer.phar
         dest: /usr/local/bin/composer
         mode: a+x
     install:
     - name: "Install app deps"
       shell: composer install
       become: yes
       become_user: app
       args:
         creates: /app/vendor/
         chdir: /app/
     setup:
     - name: "Create start script"
       copy:
         content: |
           #!/bin/bash
           php -S 0.0.0.0:8000 -t public/
         dest: /app/start.sh
         owner: app
         group: app
         mode: 0755
     - raw: echo `date` > /app/version.txt
     - raw: chown app:app /app/version.txt
   git:
   - add: /
     to: /app
     owner: app
     group: app
   

   project: symfony-demo
   configVersion: 1
   ---
   
   image: ~
   from: ubuntu:16.04
   docker:
     WORKDIR: /app
     # Non-root user
     USER: app
     EXPOSE: "80"
     ENV:
       LC_ALL: en_US.UTF-8
   shell:
     beforeInstall:
     - apt-get update
     - apt-get install -y locales ca-certificates curl software-properties-common
     - locale-gen en_US.UTF-8
     - groupadd -g 242 app
     - useradd -m -d /app -g 242 -u 242 -s /bin/bash app
     # https://askubuntu.com/posts/490910/revisions
     - LC_ALL=C.UTF-8 add-apt-repository -y ppa:ondrej/php
     - apt-get update
     - apt-get install -y php7.2 php7.2-sqlite3 php7.2-xml php7.2-zip php7.2-mbstring php7.2-intl
     - curl -LsS https://getcomposer.org/download/1.4.1/composer.phar -o /usr/local/bin/composer
     - chmod a+x /usr/local/bin/composer
     install:
     - cd /app
     # NOTICE: Always use `composer install` command in real world environment!
     - su -c 'composer update' app
     setup:
     - "echo '#!/bin/bash' >> /app/start.sh"
     - echo 'php -S 0.0.0.0:8000 -t public/' >> /app/start.sh
     - echo `date` > /app/version.txt
     - chown app:app /app/start.sh /app/version.txt
     - chmod +x /app/start.sh
   git:
   - add: /
     to: /app
     owner: app
     group: app
   

Step 2: Build and Run the Application

Let’s build and run our first application.

1. cd to the project root directory.

2. Build an image:

   werf build --stages-storage :local
   

   There is a known issue in composer, so if you’ve got the proc_open(): fork failed - Cannot allocate memory error when running build add 1GB swap file. How to add swap space read here.

3. Run a container from the image:

   werf --stages-storage :local run --docker-options="-d -p 8000:8000" -- /app/start.sh
   

4. Check that the application runs and responds:

   curl localhost:8000
   

Step 3: Push image into Docker registry

werf can be used to push a built image into Docker registry.

1. Run local Docker registry:

   docker run -d -p 5000:5000 --restart=always --name registry registry:2
   

2. Publish image with werf using custom tagging strategy with docker tag v0.1.0:

   werf publish --stages-storage :local --images-repo localhost:5000/symfony-demo --tag-custom v0.1.0
   

What Can Be Improved

This example has space for further improvement:

• Set of commands for creating start.sh can be easily replaced with a single git command, and the file itself stored in the git repository.
• As we copy files with a git command, we can set file permissions with the same command.
• composer install instead of composer update should be used to install dependencies with versions fixed in files composer.lock, package.json and yarn.lock. Also, it’s best to first check these files and run composer install when needed. To solve this problem werf have so-called stageDependencies directive.

These issues are further discussed in reference.