ansible-nginx-uwsgi-supervisor
==============================

An Ansible role to setup and manage a UWSGI app via supervisor, and served up on a NGINX web server.  The goal of this
role is to make deployment of WSGI app as a simple and sane as possible.  Additionally the role provides sane defaults
for logging and folder structure setup.

Requirements
------------

- aptitude or python-apt (required by apt tasks)
- python > 2.5 (required by ini_file tasks)

This role is designed to work against a modern Ubuntu system.  (Tested on Ubuntu 13.10 and 14.04)  It should 
theoretically work on older versions of Ubuntu or Debian based systems.

Role Variables
--------------

There are a few crucial variables that you need to configure for your particular WSGI powered app.  They are broken up
into sections and described below:

### App Settings

- app_name:
    - The name of WSGI app to manage via this role.
    - Used as a prefix through out the role.
- app_root_path:
    - The path to the root folder of the app.
    - Default: {{ web_root_path }}/{{ app_name }}_webapp"

### NGINX

- app_nginx_hostname:
    - The DNS hostname that the application serves.
    - Default: localhost
- app_nginx_app_static: 
    - The path to the static elements of the site (templates, CSS, images, etc.)
    - Default: app_root_path/app_name/static/

### UWSGI

- app_uwsgi_port: 
    - The port number that the WSGI runs on and accepts requests forwarded from NGINX.
    - Default: 8001
- app_uwsgi_executable:
    - The method executed by UWSGI to create a WSGI running app.  Usually a WSGI factory method or module in the app.
    - Default: app:make_wsgi_app()

### General Web:

These variables are not as crucial to configure.  They do give good defaults for configuring the system in a consistent,
POSIX/LSB-friendly and user-friendly manner.  See the section on Default File Structure for more details.

- web_root_path:
    - The root of the entire web app structure include configuration and logging.
    - Default: /srv/www
- web_server_group:
    - The user group responsible for starting, stopping and managing the web and app servers on the target machine. 
    - Default: www-data

### Main (Internal) Variables

The following variables are part of the internals of the role.  However if you really want to, you can tweak them to 
work with your setup:

- web_user: 
    - The non-root user who is allowed to control web + app servers on the target machine.
    - Default: current user
- virtualenv_root_path: 
    - The common root directory of Python virtual environments associated with running the 
    UWSGI app + server.  
    - Default: /srv/www/virtualenvs/
- uwsgi_venv:
    - The virtual environment where UWSGI is installed.
    - Default: virtualenv_root/uwsgi
- app_venv: 
    - The virtual environment where the dependencies of the WSGI app is installed.  
    - Default: virtualenv_root/app_name
- nginx_app_conf: 
    - The filename of the NGINX configuration for the app.
    - Default: app_name_uwsgi_nginx.conf
- supervisor_app_config:
    - The filename of the supervisor configuration for the app.  
    - Default: app_name_supervisor.conf
- uwsgi_config_path: 
    - The path to the UWSGI configurations.
    - Default: /srv/www/config/uwsgi
- uwsgi_app_ini: 
    - The filename of the UWSGI INI configuration for the app. 
    - Default: app_name_uwsgi.ini
- uwsgi_service_name: 
    - The name of the UWSGI setup for the app according to supervisor.  
    - Default: app_name_uwsgi

Example Playbook
----------------

The simplest way to include the role in your playbook is to copy the below configuration.  Remember to modify the 
app_name, nginx_hostname and uwsgi_app_executable parameters especially.
         
    - hosts: servers
      sudo: yes
    
      roles:
          - { role: ansible-nginx-uwsgi-supervisor, 
              app_name: app, 
              app_nginx_hostname: app.domain.net,
              app_uwsgi_port: 8080, 
              app_uwsgi_executable: "app.build:make_wsgi_app()" }

A comprehensive example can be found in the [ansible-rookeries role] 
(https://bitbucket.org/dorianpula/ansible-rookeries) that uses this role as a base to deploy a Flask-based webapp.

Default File Structure
----------------------

By default the role will organize files in the following directory structure:

    /srv/www
    ├── config
    │   ├── nginx -> /etc/nginx
    │   ├── supervisor -> /etc/supervisor
    │   └── uwsgi
    ├── logs
    │   ├── nginx -> /var/log/nginx
    │   ├── supervisor -> /var/log/supervisor
    │   └── uwsgi
    ├── app_webapp
    │   ├── requirements.txt
    │   └── app
    └── virtualenvs
        ├── app
        └── uwsgi

License
-------

BSD

Author Information
------------------

Dorian Pula

- twitter: @dorianpula
- email: dorian.pula at amber-penguin.software.ca
- www: http://amber-penguin-software.ca

This role is a spin-off of the technology developed for the [Rookeries project] (http://rookeri.es/)