srid/rust-nix-template

Rust project template with Nix (Flakes) and VSCode support

A template Rust project with fully functional and no-frills Nix support, as well as builtin VSCode configuration to get IDE experience without any manual setup (just install direnv, open in VSCode and accept the suggestions). It uses crane, via rust-flake.

Note

If you are looking for the original template based on this blog post's use of crate2nix, browse from this tag. The evolution of this template can be gleaned from releases.

Adapting this template

• Run nix develop to have a working shell ready before name change.
• Change name in Cargo.toml.
• Run cargo generate-lockfile in the nix shell
• There are two CI workflows, and one of them uses Nix which is slower (unless you configure a cache) than the other that is based on rustup. Pick one or the other depending on your trade-offs.

Development (Flakes)

This repo uses Flakes from the get-go.

# Dev shell
nix develop

# or run via cargo
nix develop -c cargo run

# build
nix build

We also provide a justfile for Makefile'esque commands.

Discussion

• Zulip

See Also

• nixos.wiki: Packaging Rust projects with nix

rust-nix-template's Issues

Revamp this template to use `dream2nix`

Already having it working in a private project; just need to port it.

Direnv not working

Using direnv doesn't seem to start the shell but nix develop does.

direnv: loading ~/Projects/rust/rust-nix-template/.envrc
direnv: using flake
direnv: nix-direnv: using cached dev shell

### ️🔨 Welcome to the Nix devshell ###

Available commands:

## Commands

  , fmt    : Auto-format project tree
  , run    : Run the project executable
  , watch  : Watch for changes and run the project executable
/nix/store/09g3fqxa257s69yr080a989i2bham1zj-nix-direnv-2.3.0/share/nix-direnv/direnvrc:238: pop_var_context: head of shell_variables not a function context
/nix/store/09g3fqxa257s69yr080a989i2bham1zj-nix-direnv-2.3.0/share/nix-direnv/direnvrc:1073: pop_var_context: head of shell_variables not a function context
environment:1: pop_var_context: head of shell_variables not a function context
direnv: error exit status 1

I found some information about how it stems from bash in nixpkgs-unstable but switching to 22.11 or 23.05 didn't help so unclear.

Switch to `crane` or `dream2nix`

https://old.reddit.com/r/rust/comments/ul3ccv/introducing_crane_composable_and_cacheable_builds/

I have crane working in a private project already.

Hover not working

Hover over even standard library functions are not working in VSCode.

macOS `cargo-watch` fails to build (bin/run broken)

NixOS/nixpkgs#146349

Unable to compile Reqwest via nix-shell.

I've a simple project where I'm using reqwest and ring.

Cargo.toml

[dependencies]
reqwest = { version = "0.11.24", features = ["blocking", "rustls-tls"], default-features = false }
ring = "0.17.8"

main.rs

fn main(){
     let client = reqwest::blocking::Client::new();
    dbg!(client);
}

I do have ld but the issue still persists, Do you have any suggestion? Can understand it doesn't relate to the flake itself.

buildRustCrate is deprecated

When cloning the repo and trying to run nix run it errors with the following.

trace: warning: `buildRustCrate` is deprecated, use `buildRustCrateForPkgs` instead
trace: warning: `buildRustCrate` is deprecated, use `buildRustCrateForPkgs` instead
error: store path '/nix/store/v3svm8vpdb16pd1iblkh3dg4rhg8c0wq-rust-nix-template-crate2nix' is not allowed to have references

There's a section in the crate2nix FAQ about this.
https://github.com/kolloch/crate2nix#i-get-a-warning-about-buildrustcrate-being-deprecated-in-favor-of-buildrustcrateforpkgs

vscode: Autoformat on save

One solution: srid/nixci@b33ad2f

Fails to build when using packages from git in Cargo.toml

I replaced the line in the example Cargo.toml: clap = "23.2.1" to clap = { git="https://github.com/clap-rs/clap" } and it fails to build.
When getting the nix log of nix develop:

@nix { "action": "setPhase", "phase": "unpackPhase" }
unpacking sources
unpacking source archive /nix/store/ayx76ymm5r1808sl2dyzpbs9jpsshv3m-zp6ag6v7ilzhs2gmpyqr279rml3d78ki-source
source root is zp6ag6v7ilzhs2gmpyqr279rml3d78ki-source
@nix { "action": "setPhase", "phase": "buildPhase" }
building
++ crate2nix generate -f ./Cargo.toml -o Cargo-generated.nix -h /nix/store/s3n05229i2z88ing067ys1hr3kmq00vq-rust-nix-template-crate2nix/crate-hashes.json
Error: while retrieving metadata about ./Cargo.toml: Error during execution of `cargo metadata`: error: could not load Cargo configuration

Caused by:
  could not parse TOML configuration in `/nix/store/s3n05229i2z88ing067ys1hr3kmq00vq-rust-nix-template-crate2nix/cargo/config`

Caused by:
  could not parse input as TOML

Caused by:
  redefinition of table `source.https://github.com/clap-rs/clap` for key `source.https://github.com/clap-rs/clap` at line 10 column 1

crate2nix failed.
== cargo/config (BEGIN)
    [source.crates-io]
    replace-with = "vendored-sources"
    
    [source."https://github.com/clap-rs/clap"]
    git = "https://github.com/clap-rs/clap"
    rev = "a11ca85e8fd401e07c8330980d0af090a3d35d03"
   branch = "master"
    replace-with = "vendored-sources"
    
    [source."https://github.com/clap-rs/clap"]
    git = "https://github.com/clap-rs/clap"
    rev = "a11ca85e8fd401e07c8330980d0af090a3d35d03"
    branch = "master"
    replace-with = "vendored-sources"
    
    
    [source.vendored-sources]
    directory = "/nix/store/z6w7g6izihmyvkphphsyp0hxn6zz26v9-deps"

== cargo/config (END)

== crate-hashes.json (BEGIN)
    {"clap 3.0.0-beta.2 (git+https://github.com/clap-rs/clap#a11ca85e8fd401e07c8330980d0af090a3d35d03)":"d57b43b2572f4ec4fd5f2b33a05d5189d216cba28e53a0d9b6826ee4d2ca5429","clap_derive 3.0.0-beta.2 (git+https://github.com/clap-rs/clap#a11ca85e8fd401e07c8330980d0af090a3d35d03)":"d57b43b2572f4ec4fd5f2b33a05d5189d216cba28e53a0d9b6826ee4d2ca5429"}
== crate-hashes.json (END)

== ls -la (BEGIN)
total 60
drwxr-xr-x 6 nixbld1 nixbld 4096 Jan  1  1970 .
drwx------ 3 nixbld1 nixbld 4096 Jul  7 19:05 ..
drwxr-xr-x 3 nixbld1 nixbld 4096 Jan  1  1970 .github
-rw-r--r-- 1 nixbld1 nixbld   28 Jan  1  1970 .gitignore
drwxr-xr-x 2 nixbld1 nixbld 4096 Jan  1  1970 .vscode
-rw-r--r-- 1 nixbld1 nixbld 6613 Jan  1  1970 Cargo.lock
-rw-r--r-- 1 nixbld1 nixbld  347 Jan  1  1970 Cargo.toml
-rw-r--r-- 1 nixbld1 nixbld 1151 Jan  1  1970 README.md
drwxr-xr-x 2 nixbld1 nixbld 4096 Jan  1  1970 bin
-rw-r--r-- 1 nixbld1 nixbld  320 Jan  1  1970 default.nix
-rw-r--r-- 1 nixbld1 nixbld 3349 Jan  1  1970 flake.lock
-rw-r--r-- 1 nixbld1 nixbld 3331 Jan  1  1970 flake.nix
-rw-r--r-- 1 nixbld1 nixbld  318 Jan  1  1970 shell.nix
drwxr-xr-x 2 nixbld1 nixbld 4096 Jan  1  1970 src

I'm also getting a deprecation warning about buildRustCrate

trace: warning: `buildRustCrate` is deprecated, use `buildRustCrateForPkgs` instead

Regarding `RUST_SRC_PATH`

# FIXME: Is this correct? Should it use rust-overlay instead?
RUST_SRC_PATH = "${pkgs.rust.packages.stable.rustPlatform.rustLibSrc}";

This would work in most cases, but ideally, the rust-src component is on par with the active rustc toolchain (that is how rustup does it).

I source the rust-src component from mozillapkgs and export RUST_SRC_PATH like so (I think oxalica/rust-overlay also exposes the same rust-src component through rust-bin.<channel>.latest.rust-src):

RUST_SRC_PATH = "${rust-src}/lib/rustlib/src/rust/library";

RUST_SRC_PATH should contain the following:

alloc/        panic_unwind/       rustc-std-workspace-alloc/  stdarch/
backtrace/    proc_macro/         rustc-std-workspace-core/   term/
core/         profiler_builtins/  rustc-std-workspace-std/    test/
panic_abort/  rtstartup/          std/                        unwind/

There has been some discussion about providing rust-src from the nix store and rust-analyzer (rust-analyzer tries to write a Cargo.lock to the nix store and fails) but I have had no trouble with this.

I use this in my rust + nix flake setup (which has been modified heavily based on your template, thanks for that).

Switch to `crane`, but via a flake-parts module

juspay/rust-flake#1

vscode: add debugging support (codelldb)

cf. https://github.com/NixOS/nixpkgs/tree/d600f006643e074c2ef1d72e462e218b647a096c/pkgs/misc/vscode-extensions/vscode-lldb

Make sure to mention that Cargo.lock should be regenerated after renaming the project.

This is normal for Rust development. But it does introduce some confusion when the project only mentions changing Cargo.toml and flake.nix.

It will also give some vague error, as it will try to find the new package in the nix store. But it is obviously not there, as the project doesn't have that name in the store.

How to make more targets available

I'm trying to build a Rust project that uses the wasm32-unknown-unknown target.

How can I make it available using this template?