Good call on using calibre – the reading experience in calibre isn’t as nice as some of the other apps (foliate is so far my preferred epub reader), but somehow converting from epub to epub (lol?) in calibre did produce a new version that seems to work just fine in foliate!
jordan0day
Benjamin-Philip
Calibre excels at converting books and maintaining a library. Its’ UX is subpar, and fixing that is effectively impossible because its maintainer (Kovid Goyal) is very cranky.
What I do is I set my preferred reader for EPUBs to Foliate and the preferred format to EPUB in Calibre and then convert the original copy that I have (usually KFX, AZW3, or MOBI) to EPUB. Then I whenever I select a book in Calibre it pops up Foliate instead of Calibre’s viewer.
2
plcholder
plcholder
Apologies, I dont want to hijack this thread with something that is off topic but wow, ive just downloaded calibre and so far the customization options are great. I normally dont read epub on my computer , my complaint was made on the pdf version of the book, but the font size on the epub looks normal and calibre allows me to increase it easily
so thank you for the suggestion
2
waseigo
plcholder
great video, I really like the “sqlite should be thought as part of your app, rather than a separate db server”
1k writes a second “limit” seems quite low actually, also the per-tenant stuff looks super cool didnt know you can do this, I wonder if one could build an app were paying customers get a per tenant instance, while the rest just share one
1
waseigo
That would be cool, even beyond distinguishing between paying/non-paying customers! It would help massively with fulfilling GDPR requests. Oh, you want your data? Here you go! (Share the .db file.)
You can do this with Ecto and a dynamic repository, similarly to how we switch between Repo and the :nt dynamic repo that holds the original Northwind Traders database in Northwind Elixir Traders. But even better would be to have one GenServer per user-specific (or company/team-specific) SQLite database, because then every user/company/team writes to a different file, so the write contention issue are also mitigated to an extent!
1
plcholder
waseigo
The biggest challenge I foresee is applying migrations so that all tenant-specific databases have the same schema. Upon user sign-up, you’d have to create the database and apply all migrations. You’d also need to increase the maximum number of open file descriptors with ulimit, if you have too many users. An interesting discussion.
Also, you couldn’t perform cross-db queries; but given that you can use Task.async_stream/3 across the repos, and access is crazy fast on NVMe (and even SSD), and that each open SQLite DB also has some in-memory cache, the task then becomes writing a function that aggregates the results of multiple queries that you run in parallel across the databases.
On the other hand, it also means that the memory requirements scale with the number of tenants, depending on how you set up the size of the pool and the page-cache size. At the very least, it makes sense to not leave Repo processes of inactive tenants running all the time, but to start each tenant’s dynamic repo at login, and stop it at logout. Authentication would still require a central database.
The more I think about it, the more I like it, at the bare minimum as an interesting exercise, especially if coupled with OpenTelemetry so that you can track things on the LiveDashboard.
Edit: never used encryption with SQLite, but this could also be a way to have each tenant’s db encrypted with a different key.
1