Cargo: Override the target directory

[SimonSapin]

Cargo writes build results to a target directory next Cargo.toml. I’d like to have a configuration key in .cargo/config to override this location. Ideally, this configuration would be a template based on the project name or path to the source directory: target_dir = "~/tmp/cargo/{}" would expand to /home/simon/tmp/cargo/rust-url or /home/simon/tmp/cargo/home/simon/projects/rust-url.

(Motivation: ~/tmp is ignored in my backups. Ignoring all directories named target is risky as they’re not necessarily from Cargo build results. For what it’s worth, my ~/tmp/servo-build is currently 2.2 GB (although not using Cargo.))

[SimonSapin]

As a work-around, I can make target (the one next to Cargo.toml) a symlink. Not as nice as a system-wide config that would get automatically applied to every project, but good enough to not make this request as pressing.

[SimonSapin]

Closing, since I’m happy with symlinks. (Especially now that Servo has upgraded to a Rust version that fixes https://github.com/rust-lang/rust/issues/16496.)

[paul-hammant]

Actually, I think the Cargo.toml file itself could name where the target directory is.

[SimonSapin]

For what it’s worth, these days Servo’s build system as configuration to set the CARGO_TARGET_DIR environment variable, which is how Cargo allows that location to be overridden.

[paul-hammant]

If so, a one-liner could be similar to:

CARGO_TARGET_DIR=foo; cargo run args

Cool.

cargo --target-dir=foo run args

Would be more unix-like, but I'll settle for the former :)

[SimonSapin]

CARGO_TARGET_DIR=foo; cargo run args

Without the semi-colon, in order to set the variable for that command only.

[paul-hammant]

Yes, you're right.

[mcandre]

Closing, since I’m happy with symlinks.

Unsatisfactory for Windows.

CARGO_TARGET_DIR

Unsatisfactory for scripting; this value should be configurable from the Cargo.toml file itself.

[kpcyrd]

I think Cargo.toml is a bad place for this, given that this file is committed to git and shared across multiple computers. I think this should go into $HOME/.cargo/config.

This feature would help a lot for backups, I currently have to exclude every target/ folder manually.

[sfackler]

Windows supports symlinks.

[mcandre]

I think Cargo.toml is a bad place for this, given that this file is committed to git and shared across multiple computers. I think this should go into $HOME/.cargo/config.

That would be worse for per-project configurations.

[sfackler]

You can put a .cargo/config in the repository.