Automating the starting of the SQL and API servers - TheEvergreenStateCollege/upper-division-cs-23-24 GitHub Wiki

Auto-Restart Docker PostgreSQL and API Server

A. Auto-Restart Docker PostgreSQL:

If you run docker ps and don't see a running database, follow these steps:

docker run -e POSTGRES_PASSWORD=<changeMe> --name=pg --restart always -d -p 5432:5432 postgres:14

This command ensures a persistent database by restarting the Docker container always, assuming you named your container pg in the run command above.

sudo docker exec -u postgres -it pg psql

This connects connects an interactive terminal to give you a good check that it is running.

B. Auto-Start Your API Server:

Below, we will call <REPO_DIR> the directory where you cloned the monorepo. If you followed the homework instructions, it will be ~/src/upper-division-cs

Step 1: Modify a startup Script

We will modify the following script in (api-server-start.sh): Substitute for <REPLACE_WITH_YOUR_API_SERVER_DIR> with the location of your API express server, wherever you put it when we did the Google Search Hits exercise.

It will look similar to /home/ubuntu/src/upper-division-cs/web-24wi/assignments/<YOUR_GITHUB_USERNAME>/api-server.

If you want to remind yourself where you put these files in the monorepo, you can run

find ~/ -name "search-hit*"

This will look for files that match the pattern search-hit*, which means any filenames that begin with search-hit followed by any other characters or empty. In the list of results, look for your Github username.

#!/bin/bash

export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"

# Port for the web server
PORT=5000

# Check if the port is in use
if ! lsof -i :$PORT > /dev/null
then
  echo "Port $PORT is not in use. Starting the application..."
  cd <REPLACE_WITH_API_SERVER_DIR>
  git checkout main
  git pull
  /usr/local/bin/npm run dev
else
  echo "Port $PORT is already in use. Nothing to do. If this is a zombie process, run>>> . ~/port-checker.sh"
fi

Step 2: Create a Symlink for npm

sudo ln -s /home/ubuntu/.nvm/versions/node/v20.11.0/bin/npm /usr/local/bin/npm

Step 3: Set Up a Cron Job for Local Restart and Checking

Run crontab -e and insert these two lines at the bottom:

* * * * * ~/src/upper-division-cs/web-24wi/scripts/api-server-start.sh
@reboot ~/src/upper-division-cs/web-24wi/scripts/api-server-start.sh

The first one runs every minute to check if the server is running and starts it if not. The second one runs a script right after a server reboot

Step 3.1: Set Up a Cron Job for After a Sudo Reboot

Run sudo crontab -e and add the following line at the bottom:

@reboot ~/src/upper-division-cs/web-24wi/scripts/api-server-start.sh

Step 4: Install the Mail App

sudo apt install mailutils

Run through the setup, pick a local installation to simplify configuration, and then run:

mail

...to view your messages.

Step 5: Test Your Webpage

Make sure your registered domain name (<YOUR_SUBDOMAIN>.arcology.builders) works and check that ports 5000 and 5432 are in LISTEN.

These steps provide a comprehensive guide to automatically restarting Docker PostgreSQL and an API server, along with additional details for monitoring and troubleshooting. Cron jobs are a critical piece of automation, they handle all sorts of tasks on the local level. I hope this helped get past any blockage.

Finally for a live example: here is mine up and running: http://pswish-corp.arcology.builders:5000/ and http://pswish-corp.arcology.builders:5000/api/product

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