Copy files to the target directory after build - rust

Question

Let's assume I have a game with the following directory structure:
/src
/resources
Cargo.toml
I would like cargo build to copy the files in the resources directory and paste them in the same directory as the executable file.
I know it is possible to do this using a custom build script, but this seems to be a common case that deserves special treatment. So the question is: does cargo provide a standard way of copying files to the target directory (using just Cargo.toml)?

Answer 1

No, it doesn't.
You can move files around with build scripts, but these are run before your crate is built because their sole purpose is to prepare the environment (e.g. compile C libraries and shims).
If you think this is an important feature, you can open a feature request in Cargo issue tracker.
Alternatively, you can write a makefile or a shell script which would forward all arguments to cargo and then copy the directory manually:
#!/bin/bash
DIR="$(dirname "$0")"
if cargo "$#"; then
[ -d "$DIR/target/debug" ] && cp -r "$DIR/resources" "$DIR/target/debug/resources"
[ -d "$DIR/target/release" ] && cp -r "$DIR/resources" "$DIR/target/release/resources"
fi
Now you can run cargo like
% ./make.sh build

Answer 2

I can't solve this for crates (as the accepted answer says) but for a "single" binary that needed a file to run correctly, this works for me.
use std::env;
use std::path::Path;
use std::path::PathBuf;
fn main() {
println!("cargo:rerun-if-changed=config.json");
println!("cargo:warning=Hello from build.rs");
println!("cargo:warning=CWD is {:?}", env::current_dir().unwrap());
println!("cargo:warning=OUT_DIR is {:?}", env::var("OUT_DIR").unwrap());
println!("cargo:warning=CARGO_MANIFEST_DIR is {:?}", env::var("CARGO_MANIFEST_DIR").unwrap());
println!("cargo:warning=PROFILE is {:?}", env::var("PROFILE").unwrap());
let output_path = get_output_path();
println!("cargo:warning=Calculated build path: {}", output_path.to_str().unwrap());
let input_path = Path::new(&env::var("CARGO_MANIFEST_DIR").unwrap()).join("config.json");
let output_path = Path::new(&output_path).join("config.json");
let res = std::fs::copy(input_path, output_path);
println!("cargo:warning={:#?}",res)
}
fn get_output_path() -> PathBuf {
//<root or manifest path>/target/<profile>/
let manifest_dir_string = env::var("CARGO_MANIFEST_DIR").unwrap();
let build_type = env::var("PROFILE").unwrap();
let path = Path::new(&manifest_dir_string).join("target").join(build_type);
return PathBuf::from(path);
}
This is a mess and I'm very new to Rust. Improvements welcome.