Issue geerlingguy#301: Move Docker Flask example into repository and update for Ubuntu 20.04.

Author: geerlingguy

.travis.yml

@@ -24,6 +24,10 @@ env:
     distro: ubuntu2004
     test_idempotence: false
 
+  - playbook: docker-flask.yml
+    distro: ubuntu2004
+    test_idempotence: false
+
   - playbook: docker-hubot.yml
     distro: ubuntu2004
     test_idempotence: false

README.md

@@ -83,6 +83,7 @@ Here is an outline of all the examples contained in this repository, by chapter:
 
   - [`docker`](docker/): Very simple playbook demonstrating Ansible's ability to manage Docker container images.
   - [`docker-hubot`](docker-hubot/): Slightly more involved example of Ansible's ability to manage and run Docker container images.
+  - [`docker-flask`](docker-flask/): A sample Flask app built with Ansible playbooks running inside the container.
 
 ### Chapter 16
 

docker-flask/README.md

@@ -0,0 +1,43 @@
+# Ansible configuration to build Flask App inside Docker Container
+
+## Background
+
+[Docker](https://www.docker.com/) is used to build and manage linux containers. [Ansible](http://www.ansible.com/) is useful in managing the Docker container lifecycle.
+
+This Vagrant profile uses Ansible to configure a local VM with Docker, then it uses Ansible to build and run three containers for a simple Flask + MySQL web app stack, Docker-style:
+
+  - `www`: Flask app on an Ubuntu container.
+  - `db`: MySQL database on an Ubuntu container.
+  - `data`: MySQL data volume on a Busybox container (for persistence).
+
+> Note: These examples are intended to highlight how Ansible intracts with the Docker container lifecycle. There are a number of other ways to manage container builds and orchestration, like Docker Compose, Kubernetes, etc. This example is not intended to necessarily be the 'best practice' for every situation.
+
+## Getting Started
+
+This README file is inside a folder that contains a `Vagrantfile` (hereafter this folder shall be called the [vagrant_root]), which tells Vagrant how to set up your virtual machine in VirtualBox.
+
+To use the vagrant file, you will need to have done the following:
+
+  1. Download and Install [VirtualBox](https://www.virtualbox.org/wiki/Downloads)
+  2. Download and Install [Vagrant](https://www.vagrantup.com/downloads.html)
+  3. Install [Ansible](http://docs.ansible.com/ansible/latest/intro_installation.html)
+  4. Open a shell prompt (Terminal app on a Mac) and cd into the folder containing the `Vagrantfile`
+  5. Run the following command to install the necessary Ansible roles for this profile: `$ ansible-galaxy install -r requirements.yml`
+
+Once all of that is done, you can simply type in `vagrant up`, and Vagrant will create a new VM, install the base box, and configure it.
+
+Once the new VM is up and running (after `vagrant up` is complete and you're back at the command prompt), you can log into it via SSH if you'd like by typing in `vagrant ssh`. Otherwise, the next steps are below.
+
+### Setting up your hosts file
+
+You need to modify your host machine's hosts file (Mac/Linux: `/etc/hosts`; Windows: `%systemroot%\system32\drivers\etc\hosts`), adding the line below:
+
+    192.168.33.39  docker-flask.test
+
+After that is configured, you could visit http://docker-flask.test/ in a browser, and you'll see the test page, confirming the Flask container can communicate with the MySQL container.
+
+If you'd like additional assistance editing your hosts file, please read [How do I modify my hosts file?](http://www.rackspace.com/knowledge_center/article/how-do-i-modify-my-hosts-file) from Rackspace.
+
+## Author Information
+
+Created by by [Jeff Geerling](https://www.jeffgeerling.com/), as an example in [Ansible for DevOps](https://www.ansiblefordevops.com/).

docker-flask/Vagrantfile

@@ -0,0 +1,25 @@
+# -*- mode: ruby -*-
+# vi: set ft=ruby :
+
+VAGRANTFILE_API_VERSION = "2"
+
+Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
+  config.vm.box = "geerlingguy/ubuntu2004"
+  config.vm.network :private_network, ip: "192.168.33.39"
+  config.ssh.insert_key = false
+
+  config.vm.hostname = "docker-flask.test"
+  config.vm.provider :virtualbox do |v|
+    v.name = "docker-flask.test"
+    v.memory = 1024
+    v.cpus = 2
+    v.customize ["modifyvm", :id, "--natdnshostresolver1", "on"]
+    v.customize ["modifyvm", :id, "--ioapic", "on"]
+  end
+
+  # Enable provisioning with Ansible.
+  config.vm.provision "ansible" do |ansible|
+    ansible.playbook = "provisioning/main.yml"
+  end
+
+end

docker-flask/provisioning/data/Dockerfile

@@ -0,0 +1,7 @@
+# Build a simple MySQL data volume Docker container.
+FROM busybox
+MAINTAINER Jeff Geerling <[email protected]>
+
+# Create data volume for MySQL.
+RUN mkdir -p /var/lib/mysql
+VOLUME /var/lib/mysql

docker-flask/provisioning/db/Dockerfile

@@ -0,0 +1,5 @@
+# A simple MySQL container.
+FROM mysql:5.7
+MAINTAINER Jeff Geerling <[email protected]>
+
+EXPOSE 3306

docker-flask/provisioning/docker.yml

@@ -0,0 +1,42 @@
+---
+- name: Build Docker images from Dockerfiles.
+  docker_image:
+    name: "{{ item.name }}"
+    tag: "{{ item.tag }}"
+    source: build
+    build:
+      path: "/vagrant/provisioning/{{ item.directory }}"
+      pull: false
+    state: present
+  with_items:
+    - { name: data, tag: latest, directory: data }
+    - { name: flask, tag: latest, directory: www }
+    - { name: db, tag: latest, directory: db }
+
+# Data containers don't need to be running to be utilized.
+- name: Run a Data container.
+  docker_container:
+    image: data:latest
+    name: data
+    state: present
+
+- name: Run a Flask container.
+  docker_container:
+    image: flask:latest
+    name: www
+    state: started
+    command: python3 /opt/www/index.py
+    ports: "80:80"
+
+- name: Run a MySQL container.
+  docker_container:
+    image: db:latest
+    name: db
+    state: started
+    volumes_from: data
+    ports: "3306:3306"
+    env:
+      MYSQL_ROOT_PASSWORD: root
+      MYSQL_DATABASE: flask
+      MYSQL_USER: flask
+      MYSQL_PASSWORD: flask

docker-flask/provisioning/main.yml

@@ -0,0 +1,14 @@
+---
+- hosts: all
+  become: true
+
+  pre_tasks:
+    - name: Update apt cache if needed.
+      apt: update_cache=yes cache_valid_time=3600
+
+  roles:
+    - role: geerlingguy.docker
+
+  tasks:
+    - import_tasks: setup.yml
+    - import_tasks: docker.yml

docker-flask/provisioning/setup.yml

@@ -0,0 +1,17 @@
+---
+# You can add users to the docker group to allow them to manage docker
+# containers. This playbook uses sudo rather than the vagrant user because
+# Ansible uses ControlPersist for SSH connections. The first time this playbook
+# runs, the docker commands would fail if run by the vagrant user, since the
+# persisted connection state isn't aware of the addition of the 'docker' group.
+- name: Add vagrant user to docker group.
+  user:
+    name: vagrant
+    groups: docker
+    append: true
+
+- name: Install Pip.
+  apt: name=python3-pip state=present
+
+- name: Install Docker Python library.
+  pip: name=docker state=present

docker-flask/provisioning/www/Dockerfile

@@ -0,0 +1,18 @@
+# A simple Flask app container.
+FROM geerlingguy/docker-ubuntu2004-ansible
+MAINTAINER Jeff Geerling <[email protected]>
+
+# Install Flask app dependencies.
+RUN apt-get update
+RUN apt-get install -y libmysqlclient-dev build-essential \
+  python3-dev python3-pip
+RUN pip3 install flask flask-sqlalchemy mysqlclient
+
+# Install playbook and run it.
+COPY playbook.yml /etc/ansible/playbook.yml
+COPY index.py.j2 /etc/ansible/index.py.j2
+COPY templates /etc/ansible/templates
+RUN mkdir -m 755 /opt/www
+RUN ansible-playbook /etc/ansible/playbook.yml --connection=local
+
+EXPOSE 80