Gravvy

About Gravvy

Author	Nnoduka Eruchalu
Date	04/18/2015
Website	http://gravvy.nnoduka.com

Gravvy just simplified shared memories!

Available on Following Devices

• iOS 7+
• Modern web browsers

Technologies

• Python
• PostgreSQL
• Amazon Web Services
• REST
• Javascript
• HTML
• CSS
• Bootstrap [Used for responsive mobile interface]

Software Description

Module	Description
settings.py	Django settings for project
settings_secret.py	Secret Django settings for project
urls.py	URL dispatcher for project
utils.py	Utility functions useful to multiple Django apps
wsgi.py	WSGI config for project
apps/	Django apps with backend logic
apps/account/	User account representation and auth. app
apps/video/	Video mashup representation app
apps/rest/	django rest framework customizations
static/	static files for project
static/css/	CSS files
static/img	Static images
static/js/	Javascript files
templates/	Django templates used by apps
templates/404.html	404 page
templates/500.html	500 page
templates/base.html	base template used by all templates
templates/rest_framework	templates used for customizing browseable REST API

3rd-party Python Modules

See requirements.txt

3rd-party Javascript Modules

• jQuery
• intl-tel-input
• libphonenumber

Design Decisions

REST API

General RESTful API Design Notes

Heroku has published a pretty good set of design notes. This project tries to comply with these as much as possible.

Resource Identifiers

Publicly exposed identifiers (IDs), such as those exposed in RESTful URLs, should not expose (or rely on) underlying technology.

This article here gives a better explanation of what to use as resource identifiers.

Virtual Env

Start a virtualenv virtual Python environment. This will create a sandbox isolated from your existing Python installation so that installed packages only exist within the sandbox:

virtualenv ENV

Activate the sandbox:

source ENV/bin/activate

Install python libraries:

pip install -r requirements.txt

Deployment

Database (On local machine)

Create User

$ psql -U postgres
$ create role nceruchalu_gravv superuser nocreaterole createdb login PASSWORD '<password>'

Create database

Create the database with the following command:

$ createdb -O nceruchalu_gravv -U nceruchalu_gravv nceruchalu_gravv

You can now access the database with the following command:

$ psql nceruchalu_gravv -U nceruchalu_gravv

Django Setup:

Settings files

The Django project is missing the gravvy/settings_secret.py file. A template version is included for help in setting up the sensitive information needed by the project.

Database Setup

Run the python manage.py migrate management command to create/update schema

Server Setup Notes

These instructions here are what I did on my Webfaction server.

Virtual ENV notes

Create webfaction app with the following settings:

• Name: gravvy
• App category: Django
• App type: mod_wsgi 4.4.11/Python 2.7
• The new application will be created in home directory (~) under ~/webapps/gravvy.
• Delete the default project folder, myproject

Install Virtualenv

• Check if virtualenv is installed on your server:

  $ virtualenv --version
  -bash: virtualenv: command not found 
  

• If Virtualenv is missing, install it on Webfaction with the following:

  $ mkdir -p ~/lib/python2.7/
  $ easy_install-2.7 pip
  $ pip install virtualenv
  

• If you get a permission denied error try this command to install virtualenv inside your user folder:

  $ pip install --user virtualenv
  

• Verify that the installation was successful:

  $ virtualenv --version
  13.0.1
  

Create a virtual environment

• Turn application directory into a virtual Python environment:

  $ cd ~/webapps/gravvy
  $ virtualenv .
  

• This adds the folders and scripts for a virtual environment inside of the directory which webfaction created for our application.

• You can now activate the created environment:

  $ source bin/activate
  (gravvy) $ 
  

Install Django and other dependencies

• Once the initial Virtualenv setup is complete, you can install Django inside it's lib/python2.7/site-packages directory

  (gravvy) $ pip install -r requirements.txt
  

• Modify httpd.conf paths to use the new python libraries and site-packages

  WSGIPythonPath /home/nceruchalu/webapps/gravvy:/home/nceruchalu/webapps/gravvy/gravvy:/home/nceruchalu/webapps/gravvy/lib/python2.7
  WSGIDaemonProcess gravvy processes=2 threads=12 python-path=/home/nceruchalu/webapps/gravvy:/home/nceruchalu/webapps/gravvy/gravvy:/home/nceruchalu/webapps/gravvy/lib/python2.7/site-packages:/home/nceruchalu/webapps/gravvy/lib/python2.7
  

Ref: http://michal.karzynski.pl/blog/2013/09/14/django-in-virtualenv-on-webfactions-apache-with-mod-wsgi/

httpd.conf Additions:

Add the following lines to ensure all requests to www.gravvy.nnoduka.com are redirected to gravvy.nnoduka.com.

LoadModule alias_module      modules/mod_alias.so

RewriteEngine on
RewriteCond %{HTTP_HOST} ^www\.gravvy\.nnoduka\.com [NC]
RewriteRule ^(.*)$ http://gravvy.nnoduka.com$1 [L,R=301]

Since we are using Apache & mod_wsgi, add this line at the end of the conf file, after WSGIScriptAlias / ...

WSGIPassAuthorization On

See this post for details.

Crontab Additions

Access crontab with:

crontab -e

Edit it to perform following functionality:

• Setup PATH, PYTHONPATH to be used by cron's environment
• Restart apache every 30 minutes. This ensures minimal downtime (if at all)
• Backup database daily using configurations hidden in config file [some values redacted]

PATH=/home/nceruchalu/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:.

12,32,52 * * * * ~/webapps/gravvy/apache2/bin/start
0 2 * * * pg_dump -U nceruchalu_gravvy -Fc nceruchalu_gravvy > $HOME/db_backups/nceruchalu_gravvy/nceruchalu_gravvy-`date +\%Y\%m\%d`.sql 2>> $HOME/db_backups/cron.log
5 2 * * * pg_dump -U nceruchalu_gravvy nceruchalu_gravvy > $HOME/db_backups/nceruchalu_gravvy/nceruchalu_gravvy.sql 2>> $HOME/db_backups/cron.log

PostgreSQL credentials file

• Create a .pgpass file in $HOME with these contents

  hostname:port:database:username:password
  

Apple Push Notification Services Setup

Follow Apple's documentation on creating .p12 files. Do not password protect these files and convert them to .pem files by using the following command:

openssl pkcs12 -in aps_production.p12 -out aps_production.pem -nodes -clcerts

Miscellaneous

To Run Development Server

python manage.py runserver 0:8000

Privacy & Terms

Generate here: http://www.bennadel.com/coldfusion/privacy-policy-generator.htm

To check resources used on server

ps -u nceruchalu -o rss,etime,pid,command | awk '{print $0}{sum+=$1} END {print "Total", sum/1024, "MB"}'

To check API performance

1. Generate a curl-format.txt file with the following contents:

   \n
               time_namelookup:  %{time_namelookup}\n
                  time_connect:  %{time_connect}\n
               time_appconnect:  %{time_appconnect}\n
              time_pretransfer:  %{time_pretransfer}\n
                 time_redirect:  %{time_redirect}\n
            time_starttransfer:  %{time_starttransfer}\n
                               ----------\n
                    time_total:  %{time_total}\n
   \n
   

2. Make a request and view the timings in seconds

   curl -w "@curl-format.txt" -s -H "Authorization: Token 57146d9e970c863266fcd89a7b175f66eefe4590" -H "Content-Type: application/json"  http://gravvy.nnoduka.com/api/v1/user/videos/ -o /dev/null