Load a resource file at runtime - file

Question

Suppose I have this architecture:
.
├── Cargo.lock
├── Cargo.toml
├── src/
│ ├── main.rs
├── rsc/
│ ├── file.xml
I want to load file.xml to fill some tables at each run. To do so I could write:
use std::fs::File;
use std::path::Path;
fn open<P: AsRef<Path>>(path: P) {
let _ = File::open(path).unwrap();
println!("file opened");
}
fn main() {
open("../rsc/file.xml");
}
But the relative path won't work if I don't run the program from src.
I could do the following:
fn main() {
include_str!("../rsc/file.xml");
}
But this will be done at compile time meaning that changing file.xml means recompiling the program so it's completely unsafe in terms of maintainability.
The other option I can see is giving the rsc path as an argument to my program but I find it a bit cumbersome since this is not an optional argument, I really need to know where my rsc directory is and I know my crate will have this architecture.
Is there something I can't see?
I saw this post: How to avoid hard-coded values in Rust
But my question is summarized in this part:
If you are deploying a binary, you may have to supply a path to where your application should find its resources.
And there's no other precision about it.

Answer 1

You can find the path to your binary using std::env::current_exe(). You can use this to find the directory that the binary is in, and then use that to load some resource relative to this directory.
For instance if your resources were in a directory 'rsrc' which was in the same directory as your binary:
let mut rsrc_dir = std::env::current_exe()
.expect("Can't find path to executable");
// Directory containing binary
rsrc_dir.pop();
// Subdir relative to binary
rsrc_dir.push("rsrc");
This would only be useful if your binary is installed with its resource files in some fixed location relative to the binary. Keep in mind that most users will not be cloning your crate from github and running it that way - typical methods for installation would include:
installing it with cargo install
using some OS specific package manager
perhaps downloading a tar or zip file and decompressing it
It seems that cargo install does not currently handle installing associated resource files (although there is an open bug for that).