Fullstack Catalog Server Documentation

This document describes how my Python/Flask + PostgreSQL project was setup AWS Ubuntu Server.

It aims to fulfill the Linux Server Configuration project rubric in:

https://review.udacity.com/#!/rubrics/2007/view

Server location

The website can be visited at:

http://ec2-3-84-208-127.compute-1.amazonaws.com

Public IP address:

3.84.208.127

Opened SSH port:

2200

Server description

The server is a EC2 t2.micro created in the N. Virginia data center, AWS Lightsail was not used so I could use the Free tier of EC2.

I setup the server with its own simple security group, to allow access on HTTP, NTP, and custom SSH port 2200. Blocking all other incoming traffic.

Server configuration

1. Install new packages:

Initially I could not install using apt-get, So I had to update the sources.list file.

sudo sed -i 's/us-east-1\.ec2\.//g' /etc/apt/sources.list

After this, I installed the needed tools, Apache2, PostgreSQL

sudo apt-get update
sudo apt-get install apache2
sudo apt-get install python-pip3
sudo apt-get install postgresql
sudo apt-get upgrade
sudo apt-get autoremove

2. Configuration of SSH and UFW firewall to allow traffic over SSH.

sudo ufw status
sudo ufw default deny incoming
sudo ufw default allow outgoing
sudo ufw allow 2200/tcp
sudo ufw allow www
sudo ufw allow ntp
sudo ufw enable

3. git clone the catalog project.

I got the project source code. Installed dependencies using requirements.txt.

pip3 install -r requirements.txt

4. Configuration of apache

Change the permissions of /var/html/www directory.

Update the Apache2 sites file: sites-enabled/000-default.conf

WSGIPythonPath /var/www/html/catalog/

<VirtualHost *:80>
        # ...
        WSGIScriptAlias / /var/www/html/catalog/application.wsgi
</VirtualHost>

5. I configured the PostgreSQL user: catalog and its permissions

6. I tried to run the database migration! Some trial and error was required to make the original code work:

I changed paths to config files setup as absolute. WSGI doesn't understand the project location.

7. Run the project (a bit more trial and error)

Created of an additional .wsgi file which returns an application variable to be able to run the project.

Update my Github App (used for OAuth) parameters, most importantly, the URL of the application.

sudo apt-get install apache2-dev
sudo pip3 install mod_wsgi

List of third-party resources and documentation

The part that gave me most trouble during setup was the WSGI + Apache configuration on Python 3.

• The mod_wsgi documentation allowed me to understand the background of wsgi and it's configuration parameters.
• The Pip mod_wsgi installation instructions helped me install WSGI without having to compile a new wsgi for my version of Python (3.6).
• This SO answer gave me the clue that WSGI installation had to be done differently for Python 3 than the default instructions.

Other documentation that helped:

• For some reason, AWS Ubuntu machines have a sources.list file with Amazon repositories that yield 404. This fix helped.
• Requirements files documention to install the same versions of packages consistently from local to server.

Opportunities for improvement

• Use virtualenv to setup the project dependencies, which is considered a best practice. I installed requirements.txt globally to Python 3.
• HTTPS/SSL should be added to make the application secure.