We could say that the app consists of a core and its ecosystem:
- Core:
- edapt (served by node/express, directly or indirectly via the pm2 process manager)
- Ecosystem:
- mysql: the mysql database is the most closely-tied external piece of the app (using Sequelize)
- gmail: the Gmail account that the data-email is retrieved from is also closely tied to the app (via Google Cloud Platform, Google APIs, Gmail API)
- pm2: in production, edapt is run as pm2 process to make sure the app restarts if the system server restarts
- nginx: nginx serves the app to the internet
- systemd: manages the server operating system and system "services", such as nginx, pm2, and mysql; ensures that these services restart if the system restarts
SystemD (systemd) comes with its utility command systemctl. When
everything is running in production, systemd controls these parts of the app:
- nginx (web server as a reverse proxy for the server serving the edapt web-app)
- mysql (database server)
- pm2 (process manager)
In turn, pm2 controls edapt (the core app as a pm2 process) via
node/express (the app-server). And edapt relies on mysql.
The major pieces of the edapt web-app are:
- database-api: provides tools at the interface between the JavaScript code (in the email-handler and web-app) and the mysql database
- email-handler: provides tools to retrieve data-email from Gmail, parse the email messages, and ingest the data into the mysql database (using the database-api)
- web-app
- client: client-side (web browser) code that displays the edapt web-app
- server: server-side code that connects the displayed client-side interface with the back-end mysql database (via database-api) and orchestrates regularly timed email retrieval and database-updates (via email-handler)