Building with local dependencies

[Piripant]

It seems that when building with a local dependency cross fails to load the source for that local dependency. If this is my Cargo.toml:

[dependencies]
nasatopo = { path = "../nasatopo" }

The output of cross build is:

error: failed to load source for a dependency on `nasatopo`

Caused by:
  Unable to update /nasatopo

Caused by:
  failed to read `/nasatopo/Cargo.toml`

Caused by:
  No such file or directory (os error 2)

Which is technically correct as the is not /nasatopo, but it the Cargo.toml I specified a local path, not a global one, as cross seems to understand.
Furthermore if I try to replace the relative path with a global one, the same error still happens, this time pointing to a path which is actually valid and takes to the location of the nasatopo source folder.

I think this has to do with how a docker container interfaces with the file-system, but I am not familiar and cannot tell.

[velvia]

This is hitting me as well. I even tried symlink but it doesn't work either.

[zekronium]

Cross only mounts the cargo project.

I had this issue as well and resolved it by moving the dependency into the project dir.

The path then has to be changed to
nasatopo = { path = "nasatopo" }

[reitermarkus]

Yeah, we would need to parse the Cargo.toml and find all path dependencies, then mount them inside the container.

[kornelski]

Could you mount root of the workspace?

I'm trying to build one of crates in a workspace, but running into the same problem - that crate gets moved out of its workspace.

[brahmlower]

I'm bumping into this as well, but I was hoping to solve it using the volume mount feature. I tried adding a Cross.toml file with the following content:

[build.env]
volumes = [
    "MY_DEP",
]

In my Cargo.toml I have:

[dependencies]
my_dep = { path = "../my-dep" }

However when I run cross with that environment variable set, it fails with the same error reported by @Piripant. Verbose output shows that the volume mount isn't being added:

$ MY_DEP=../my-dep cross build --target x86_64-unknown-linux-gnu --verbose
+ "rustc" "--print" "sysroot"
+ "rustup" "toolchain" "list"
+ "rustup" "target" "list" "--toolchain" "stable-x86_64-unknown-linux-gnu"
+ "rustup" "component" "list" "--toolchain" "stable-x86_64-unknown-linux-gnu"
+ "/usr/local/bin/docker" "run" "--userns" "host" "-e" "PKG_CONFIG_ALLOW_CROSS=1" "--rm" "--user" "501:20" "-e" "XARGO_HOME=/xargo" "-e" "CARGO_HOME=/cargo" "-e" "CARGO_TARGET_DIR=/target" "-e" "USER=me" "-e" "CROSS_RUNNER=" "-v" "/Users/me/.xargo:/xargo:Z" "-v" "/Users/me/.cargo:/cargo:Z" "-v" "/cargo/bin" "-v" "/Users/me/development/my-project/backend-api:/project:Z" "-v" "/Users/me/.rustup/toolchains/stable-x86_64-unknown-linux-gnu:/rust:Z,ro" "-v" "/Users/me/development/my-project/backend-api/target:/target:Z" "-w" "/project" "-i" "-t" "rustembedded/cross:x86_64-unknown-linux-gnu-0.2.1" "sh" "-c" "PATH=$PATH:/rust/bin cargo build --target x86_64-unknown-linux-gnu --verbose"
error: failed to get `my_dep` as a dependency of package `backend_api v0.1.0 (/project)`

Caused by:
  failed to load source for dependency `my_dep`

Caused by:
  Unable to update /my-dep

Caused by:
  failed to read `/my-dep/Cargo.toml`

Caused by:
  No such file or directory (os error 2)

Am I using the volume feature wrong here? As far as I can tell, I'm using it as described by the documentation.

---

Beyond my issue of using the volume feature, it looks like the volumes don't let you change where the path gets mounted in the container. The code for this is here:

if let Ok(val) = env::var(var) {
    let host_path = Path::new(&val).canonicalize()?;
    let mount_path = &host_path;
    docker.args(&["-v", &format!("{}:{}", host_path.display(), mount_path.display())]);
    docker.args(&["-e", &format!("{}={}", var, mount_path.display())]);
}

It looks like the path in the container will be the same as the canonical path on the host, which obviously won't work for us. For example, my attempted work around would result in the docker flag -v /Users/me/development/my-project/my-dep:/Users/me/development/my-project/my-dep, but we know cargo will be looking for the dependency at /my-dep.

We could expand the volume feature to respect host/container volume paths such that the environment variable MY_DEP=../my-dep:/my-dep would translate to the docker flag -v /Users/me/development/my-project/my-dep:/my-dep. @reitermarkus and @malbarbo Does that sound like a change you'd be comfortable with? If so, then I can get a PR put together for this.

[wngr]

The other possibility would be to run cross from the root dir, but be be able to give an additional working dir parameter (like docker -w).

Edit: https://github.com/rust-embedded/cross/pull/438/files solves the issue for me.

[TarekkMA]

@bplower I did face issues with the volume feature as well. But I realized the code you linked is newer than the latest release.

I installed cross from git directly and the option worked
cargo install cross --git https://github.com/rust-embedded/cross/

Edit: I did add a PR to add the option to specify the mount path #540

[mkhattab]

I think have a work around for this that perhaps may help someone. The cross command accepts a DOCKER_OPTS environment variable, so you can use that to mount volumes into the container.

For example, assuming you have a workspace like the following:

.
├── Cargo.toml
├── foo                       # `foo` has a dependency on `../bar`
│   └── Cargo.toml
└── bar
    └── Cargo.toml

# in foo/
DOCKER_OPTS="-v $(realpath ..)/bar:/bar" cross build --target x86_64-unknown-linux-gnu

On macOS the above command works for me.