PostgreSQL logging without SQL/historian modules?

I have very limited experience with Ignition, but have been tasked with specifying a minimal edge install. The customer needs a local HMI + alarm log + basic trends. However, one of the requirements is a local historical storage (~2 years, 30 tags, every 30 seconds).

Is this possible without the SQL and historian modules? If I were to pay for just the core ignition platform module + 1 vision client, would it be possible to write a custom gateway script to manually log such information into the database (local PostgreSQL)?

Yes, you can script what you need. However, you will need to use DB pens in your EasyChart trends, and Named Query bindings for other charts.

Be aware that IA offers an "Edge" product that has no DB capability at all. It cannot store more than 35 days, period. It seems you've figured that out, but I thought I'd emphasize it for others.