WARNING

This is the libnix concept integrated into cargo using a 'nix build backend', see discussion at https://lastlog.de/blog/timeline.html?filter=tag::libnix

What it can do

• extended 'cargo build' so it uses 'nix build' internally by generating nix files on the fly and then build it using 'nix build'!
• each dependency crate download/build uses its own store path and built in a sandbox so you will never have to recompile them again unless their input changes (rustc, cargo, env vars)
• the root crate builds are built in a sandbox also
• build artifacts during build can be reused during deployment (speedup, size reduction)
• most 'heavy weight' asses like the toolchain and intermediate downloads/build artifacts are in the /nix/store and NOT in target/debug or target/release so now garbage collection is done by nix-collect-garbage
• the cargo binary generates a nix-based toolchain and spawns the environment used to build (rustc, cargo, ...)
• supports build-script-build aka build.rs execution using build-parser
• can easily be used from a flake
• features the @cargo protocol (similar to the @nix protocol) which mimics cargo build's status output

What it can't do

• no .fingerprint support yet, so no fast iteration on builds

State of development

• experimental backend builds 'cargo' (itself) and klick without any issues
• project setup to use it is still a lot of work
• 'cargo build' prints a store path and requires one more manual step

How to use

Type:

nix develop
cargo build

Use custom cargo

alias cargo=/home/nixos/cargo/target/debug/cargo

Call with: CARGO_BACKEND=nix cargo build to generate files in target/debug/nix Call with: cargo build to study the traditional build and see /tmp/out but this needs a manual cleanup before each run.

Alternative calls for using the nix backend in cargo:

CARGO_BACKEND=nix cargo build
CARGO_BACKEND=legacy cargo build

nix build system

time nix build --file target/debug/nix/default.nix --impure -L --no-link --print-out-paths target --json --log-format internal-json

afterwards install it with running something like:

/nix/store/5646xcjihqq11icyxyr3s0jc89s8j1hj-cargo-targets-symlinks/bin/cargo-targets-symlinks

injecting dependencies (pkg-config, openssl, ...)

There is an easy way to inject dependencies into the cargo generated nix attributes:

1. create a file Cargo.dependencies.nix next to Cargo.lock / Cargo.toml

2. fill it with your desired nix dependencies like openssl or curl:

    { pkgs }:
    with pkgs;
    {
        deps = {
            "markup5ever_rcdom" = {
                "0.3.0" =
                    [ pkg-config openssl ];
            };
            "unicode-ident" = [ pkg-config curl ];
            "xml5ever" = {
                "0.20.0" = [];
            };
        };
    }
   

Note: The name and version of a crate can be copied from Cargo.lock but keep in mind there is no check for unused or wrongly spelled dependencies or out of date versions.

Note: This file is optional and explicitly outside of the generated nix files so it stays in your repository.

---

Cargo

Cargo downloads your Rust project’s dependencies and compiles your project.

To start using Cargo, learn more at The Cargo Book.

To start developing Cargo itself, read the Cargo Contributor Guide.

The Cargo binary distributed through with Rust is maintained by the Cargo team for use by the wider ecosystem. For all other uses of this crate (as a binary or library) this is maintained by the Cargo team, primarily for use by Cargo and not intended for external use (except as a transitive dependency). This crate may make major changes to its APIs.

Code Status

Code documentation: https://doc.rust-lang.org/nightly/nightly-rustc/cargo/

Compiling from Source

Requirements

Cargo requires the following tools and packages to build:

• cargo and rustc
• A C compiler for your platform
• git (to clone this repository)

Other requirements:

The following are optional based on your platform and needs.

• pkg-config — This is used to help locate system packages, such as libssl headers/libraries. This may not be required in all cases, such as using vendored OpenSSL, or on Windows.

• OpenSSL — Only needed on Unix-like systems and only if the vendored-openssl Cargo feature is not used.

  This requires the development headers, which can be obtained from the libssl-dev package on Ubuntu or openssl-devel with apk or yum or the openssl package from Homebrew on macOS.

  If using the vendored-openssl Cargo feature, then a static copy of OpenSSL will be built from source instead of using the system OpenSSL. This may require additional tools such as perl and make.

  On macOS, common installation directories from Homebrew, MacPorts, or pkgsrc will be checked. Otherwise it will fall back to pkg-config.

  On Windows, the system-provided Schannel will be used instead.

  LibreSSL is also supported.

Optional system libraries:

The build will automatically use vendored versions of the following libraries. However, if they are provided by the system and can be found with pkg-config, then the system libraries will be used instead:

• libcurl — Used for network transfers.
• libgit2 — Used for fetching git dependencies.
• libssh2 — Used for SSH access to git repositories.
• libz (aka zlib) — Used for data compression.

It is recommended to use the vendored versions as they are the versions that are tested to work with Cargo.

Compiling

First, you'll want to check out this repository

git clone https://github.com/rust-lang/cargo.git
cd cargo

With cargo already installed, you can simply run:

cargo build --release

Adding new subcommands to Cargo

Cargo is designed to be extensible with new subcommands without having to modify Cargo itself. See the Wiki page for more details and a list of known community-developed subcommands.

Releases

Cargo releases coincide with Rust releases. High level release notes are available as part of Rust's release notes. Detailed release notes are available in the changelog.

Reporting issues

Found a bug? We'd love to know about it!

Please report all issues on the GitHub issue tracker.

Contributing

See the Cargo Contributor Guide for a complete introduction to contributing to Cargo.

License

Cargo is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0).

See LICENSE-APACHE and LICENSE-MIT for details.

Third party software

This product includes software developed by the OpenSSL Project for use in the OpenSSL Toolkit (https://www.openssl.org/).

In binary form, this product includes software that is licensed under the terms of the GNU General Public License, version 2, with a linking exception, which can be obtained from the upstream repository.

See LICENSE-THIRD-PARTY for details.