FlaskApp

Server/App Info

• My static IP address is 52.59.100.171
• The port number I configured is 2200
• Username and password: grader, grader

Configurations in Steps

Goals

• Install Apache and configure it to serve a Python mod_wsgi application.

• Install Flask

Steps

1. Install Apache.

   After updating the package index, install Apache.

   sudo apt-get update
   sudo apt-get install apache2
   

2. Install and enable mod_wsgi.

   To install:

   sudo apt-get install libapache2-mod-wsgi python-dev
   

   To enable mod_wsgi:

   sudo a2enmod wsgi
   

3. Create a directory for the Flask application.

   Move to the /var/www directory and create a directory for your application.

   cd /var/www
   sudo mkdir catalog
   

4. Clone your Flask application into the new directory.

   Move inside your app directory and clone in your Flask application from Github.

   cd catalog
   sudo git clone {your repository clone URL}
   

   Rename the directory created by git to catalog.

   sudo mv /{git-repository-name} FlaskApp
   

5. Install Flask and SQLAlchemy inside a virtual environment.

   If pip is not installed, add it now.

   sudo apt-get install python-pip
   

   Install virtualenv.

   sudo pip install virtualenv
   

   Create a virtual environment inside your FlaskApp directory.

   cd catalog
   sudo virtualenv venv
   

   Activate the virtual environment and install Flask and SQLAlchemyinside.

   source venv/bin/activate 
   sudo pip install Flask
   sudo pip install flask-sqlalchemy
   

6. Configure files as needed and test if the installation was successful.

   Make sure your database conneciton Url matches the username and password you set up in installing and configuring PostgreSQL to work with SQLAlchemy.

   If your modules reference other files, you will need to alter filepaths. The path to your FlaskApp directory will be: /var/www/catalog/catalog.

   Test if the installation is successful and the app can run:

   sudo python __init__.py
   

   If it says Running on http://0.0.0.0:5000/, your installation was successful.

7. Configure and enable a new virtual host with Apache.

   Create a configuration file for Apache:

   sudo nano /etc/apache2/sites-available/catalog.conf
   

   And input the configuration:

   <VirtualHost *:80>
       ServerName 52.59.100.171
       ServerAdmin grader@52.59.100.171
       WSGIScriptAlias / /var/www/catalog/flaskapp.wsgi
       <Directory /var/www/catalog/catalog/>
           Order allow,deny
           Allow from all
       </Directory>
       Alias /static /var/www/catalog/catalog/static
       <Directory /var/www/catalog/catalog/static/>
           Order allow,deny
           Allow from all
       </Directory>
       ErrorLog ${APACHE_LOG_DIR}/error.log
       LogLevel warn
       CustomLog ${APACHE_LOG_DIR}/access.log combined
   </VirtualHost>
   

   Enable the virtual host.

   sudo a2ensite catalog.conf
   

   Change default site to point to app

   sudo nano /etc/apache2/sites-available/000.default.conf
   change DocumentRoot /var/www/html to  /var/www/catalog/catalog/templates
   paste 'WSGIScriptAlias / /var/www/catalog/catalog.wsgi' without the quotes just below it. save and exit from nano
   

8. Create a .wsgi file.

   Apache uses a .wsgi file to serve the Flask application. Create the file:

   cd /var/www/catalog
   sudo nano catalog.wsgi
   

   Input the configuration:

   #!/usr/bin/python
   import sys
   import logging
   logging.basicConfig(stream=sys.stderr)
   sys.path.insert(0,"/var/www/catalog/")
   
   from catalog import app as application
   application.secret_key = {Add your secret key}
   

9. Install and configure PostgreSQL

   1. Install some necessary Python packages for working with PostgreSQL: $ sudo apt-get install libpq-dev python-dev.
   2. Install PostgreSQL: $ sudo apt-get install postgresql postgresql-contrib
   3. PostgreSQL automatically creates a new user 'postgres' during its installation. So we can connect to the database by  using postgres username with: $ sudo -u postgres psql
   4. Create a new user called 'catalog' with his password: # CREATE USER catalog WITH PASSWORD 'catalog';
   5. Give catalog user the CREATEDB permission: # ALTER USER catalog CREATEDB;
   6. Create the 'catalog' database owned by catalog user: # CREATE DATABASE catalog WITH OWNER catalog;
   7. Connect to the database: # \c catalog
   8. Revoke all the rights: # REVOKE ALL ON SCHEMA public FROM public;
   9. Lock down the permissions to only let catalog role create tables: # GRANT ALL ON SCHEMA public TO catalog;
   10.Log out from PostgreSQL: # \q. Then return to the grader user: $ exit.
   11.Edit the db_seed.py and database_setup.py file:
   12.Change engine = create_engine('sqlite:///category.db') to engine = create_engine('postgresql://catalog:catalog@localhost/catalog')
   13.Remote connections to PostgreSQL should already be blocked. Double check by opening the config file: $ sudo nano /etc/postgresql/9.5/main/pg_hba.conf Source: DigitalOcean.
   

10. Restart Apache.

    sudo service apache2 restart
    

    Open your browser and navigate to the domain name or IP address you entered in the catalog.conf configuration file. If all is well, you will see your app.

References & Credits

Digital Ocean
golgtwins/Udacity-P7-Linux-Server-Configuration
Internal Server Error: Target WSGI script cannot be loaded as Python module AND IOError: [Errno 2] No such file or directory: 'client_secrets.json'