DatadogChappy

A simple flask app to deploy and run APM, Logs, Metrics, and DBM from

To get the flask app working, I followed this article. I'm going to provide a seperate outline as to get Chappy working there are a few extra steps.

• Here is the article for reference: https://medium.com/techfront/step-by-step-visual-guide-on-deploying-a-flask-application-on-aws-ec2-8e3e8b82c4f7

• Download the compressed file and extract it in the home/ubuntu/ directory of your server and follow the instructions below.

Step 1: Create an Ubuntu EC2 on AWS

• Log in to AWS Console.
• Go to EC2 Section and select Ubuntu 18.4 AMI
• Select t2.micro if you want to stay in free tier or any other instance type you want.
• Press Next until Security Groups.
• Allow HTTP (Port 80), SSH (Port 22), HTTPS (Port 443) inbound traffic and press next.
• Create/Reuse Key-pair for connecting with your instance.

Step 2: SSh into Ubuntu EC2

• Open a terminal
• Type $ ssh -i <your key name>.pem ubuntu@<Public DNS of your EC2>.
• If you encounter an error message, run $ chmod 400 .pem then try Step 2 again.

Step 3: Create/Clone Flask application inside EC2 (NOTE: I performed all of the following as the root user)

• Install Python Virtualeng

  $ sudo apt-get update
  $ sudo apt-get install python3-venv
  

• Activate the new virtual environment in a new directory

  // Create directory
  $ mkdir chappy
  $ cd chappy
  
  // Create the virtual environment
  $ python3 -m venv chp
  
  // Activate the virtual environment
  $ source chp/bin/activate
  
  // Install Flask
  $ pip install -r requirements.txt
  
  // Other important packages for Chappy:
  $ sudo apt-get install postgresql
  $ sudo apt-get install postgresql-contrib
  
  

• Setup Chappy DB

  Create a user mapping for the ubuntu user to postgres:

  $  sudo vi /etc/postgresql/14/main/pg_ident.conf
  

  Add an entry mapping ubuntu to postgres:

  # MAPNAME       SYSTEM-USERNAME         PG-USERNAME
  user1           ubuntu                  postgres
  

  Add an entry for postgres into the pg_hba.conf

  $  sudo vi /etc/postgresql/14/main/pg_hba.conf
  

  add:

  # Database administrative login by Unix domain socket
  local   all             postgres                                md5
  local   all             admin                                   md5
  

  Now we are ready to connect to postgres and set up the db. Login to postgres with the following command:

  psql -U postgres
  

  Here we are going to setup Postgres, Admin, and pgcrypto:

  $ ALTER USER postgres PASSWORD '<YOUR NEW PASSWORD>';
  $ CREATE DATABASE chappy;
  $ CREATE USER admin WITH ENCRYPTED PASSWORD 'admin';
  $ GRANT ALL PRIVILEGES ON DATABASE chappy TO admin;
  $ \q
  

  Sign in as admin:

  $ pswl -U admin -d chappy
  $ CREATE EXTENSION IF NOT EXISTS pgcrypto;
  $ \q
  

  Now let's add some tables and data to our database, in the chappy directory run the create_chappy_db.py script:

  $ python3 create_chappy_db.py
  

  You can now login to the chappy database and make sure the data is there and ready to use! Chappy is now 90% setup, and we'll just need to configure the application to be accessible on the internet!

Step 3: Run Gunicorn WSGI server to serve the Flask Application

• Install Gunicorn using

  $ pip install gunicorn
  
  

• You may need to install gunicorn for Ubuntu if you are getting a command not recognized error:

  $ sudo apt install gunicorn
  

• Test and Run Gunicorn — $ gunicorn -b 0.0.0.0:8000 fchap:app. Further modifications are possible, check out the gunicorn docs! Gunicorn is running (Ctrl + C to exit gunicorn)!

Step 4: Use systemd to manage Gunicorn

• Systemd is a boot manager for Linux. We are using it to restart gunicorn if the EC2 restarts or reboots for some reason. We create a .service file in the /etc/systemd/system folder, and specify what would happen to gunicorn when the system reboots. We will be adding 3 parts to systemd Unit file — Unit, Service, Install:

  • Unit — This section is for description about the project and some dependencies
  • Service — To specify user/group we want to run this service after. Also some information about the executables and the commands.
  • Install — tells systemd at which moment during boot process this service should start.

• With that said, create an unit file in the /etc/systemd/system directory

  $ sudo vim /etc/systemd/system/chappy.service
  

• Then add this into the file:

  [Unit]
  Description=Gunicorn instance for a simple flask app
  After=network.target
  [Service]
  User=ubuntu
  Group=ubuntu
  WorkingDirectory=/home/ubuntu/chappythreezero
  ExecStart=/home/ubuntu/chappythreezero/chp/bin/gunicorn -b localhost:8000 fchap:app
  Restart=always
  [Install]
  WantedBy=multi-user.target
  

• Then enable the service:

  $ sudo systemctl daemon-reload
  $ sudo systemctl start helloworld
  $ sudo systemctl enable helloworld
  

Step 5:

• Nginx as a reverse-proxy to accept the requests from the user and route it to gunicorn. Install Nginx —

  $ sudo apt-get nginx
  

• Start the Nginx service and go to the Public IP address of your EC2 on the browser to see the default nginx landing page ''' $ sudo systemctl start nginx $ sudo systemctl enable nginx '''

• Add the following to the top of the file /etc/nginx/sites-available/default:

  upstream fchap {
      server 127.0.0.1:8000
  }
  

  and add the following to the location config and make sure to remove 'try_files $uri $uri/ =404;':

          location / {
              # First attempt to serve request as file, then
              # as directory, then fall back to displaying a 404.
              proxy_pass http://fchap/;
              include proxy_params;
      }
  

  After setting these variables restart nginx:

  $ sudo systemctl restart nginx
  '''
  
  Now, inside your AWS account you can use the Public IPv4 DNS to hit the front end of chappy. Login as the main admin user (superuser), and from here you can assign all the chores to the test users.