enhancement(NOC-1919) add database check on application start up

[dmmc12]

Scope

Test database start up behaviour to ensure errors are captured correctly so the end user is aware of potential configuration issues.

Implementation

postgres.ts contains the constructor for creating the chatbot pool.

I've duplicated this code in application.ts and created two new functions called setupDatabaseConnection and ensureDatabaseConnection.

These two functions are used at application startup to check that you can connect to the database ai_chatbot correctly and console logged to the terminal.

17:15:18 - Starting compilation in watch mode...


17:15:19 - Found 0 errors. Watching for file changes.
Successfully connected to the database: ai_chatbot at localhost:5432
Server running on http (port 3000)

If I mistakenly use the wrong port, user, database, host or password, you will see the error console logged.

Example

17:15:58 - Starting compilation in watch mode...


17:15:59 - Found 0 errors. Watching for file changes.
Failed to establish a database connection: password authentication failed for user "ai_chatbot"

I believe it to be necessary to ensure checks are done on database connectivity but I would appreciate confirmation on whether duplicating the code was the incorrect choice here or if you have preferred suggestions.