My program is small enough that in TS/JS I'd normally just store the data in some global variable to be access from whatever elsewhere in the app. But with Rust from what I can tell this doesn't seem to be a common practice. How should i handle this?
More specifically, I need to:
- program start, fetch data from my db (DONE)
- store this data somehow somewhere
- access said data (for read only in this use case)
Thanks for any insights here!
6 Comments
mipli@programming.dev · 11 pts · 3y
I would consider just passing along the data directly to the functions that need access to it, rather than storing in a global state. If passing each piece of data along as separate parameters is a bit much, you can always create
struct Context { ... }which keeps tracks of whatever you need and pass that around.Nothing wrong with using
OnceCellas @heartlessevil@lemmy.one suggested, but I've found that passing it as an argument feels a bit better.nerdblood@programming.dev · 4 pts · 3y
I might not need global state, the more I think about it. I'll start with passing a struct and see where that gets me, thanks!
nous@programming.dev · 3 pts · 3y
Using OnceCell for inviting some static resource, like a regex expression. Or for storing something like a internal cache for a function is ok. But I would avoid using it to hold a application wide state that anything can drop in and modify. Passing around application state where it is needed is generally much better and far easier to test things with.
heartlessevil@lemmy.one · 8 pts · 3y
From your description it sounds like you want OnceCell which is a relatively new feature; previously you'd use lazy_static
nerdblood@programming.dev · 3 pts · 3y
Yeah I tried out lazy_static, but the compiler was strongly urging me not to use it since it's being deprecated. Thanks, I didn't know about OneCell.
dvektor@programming.dev · 2 pts · 3y
Glad I clicked on this... I'd never heard of /used OnceCell, and have a literally identical need in a program I'm writing. Nice!