garage/nix/compile.nix

{
  /* build inputs */
  nixpkgs,
  crane,
  rust-overlay,

  /* parameters */
  system,
  git_version ? "unknown",
  target ? null,
  release ? false,
  features ? null,
}:

let
  log = v: builtins.trace v v;

  pkgs =
    import nixpkgs {
      inherit system;
      overlays = [ (import rust-overlay) ];
    };

  inherit (pkgs) lib;

  toolchain = pkgs.symlinkJoin {
    name = "garage-rust-toolchain-1.78";
    paths = [
      (pkgs.rust-bin.stable."1.78.0".default.override {
        targets = [
          "arm-unknown-linux-musleabihf"
          "aarch64-unknown-linux-musl"
          "i686-unknown-linux-musl"
          "x86_64-unknown-linux-musl"
        ];
        extensions = [
          "rust-src"
          "rustfmt"
        ];
      })
      pkgs.clang
      pkgs.mold
      pkgs.protobuf
    ];
  };

  craneLib = (crane.mkLib pkgs).overrideToolchain toolchain;

  src = craneLib.cleanCargoSource ../.;

  /* We ship some parts of the code disabled by default by putting them behind a flag.
     It speeds up the compilation (when the feature is not required) and released crates have less dependency by default (less attack surface, disk space, etc.).
     But we want to ship these additional features when we release Garage.
     In the end, we chose to exclude all features from debug builds while putting (all of) them in the release builds.
  */
  rootFeatures = if features != null then
    features
  else
    ([ "bundled-libs" "lmdb" "sqlite" "k2v" ] ++ (if release then [
      "consul-discovery"
      "kubernetes-discovery"
      "metrics"
      "telemetry-otlp"
      "syslog"
    ] else
      [ ]));

  featuresStr = lib.concatStringsSep "," rootFeatures;

  /* We compile fully static binaries with musl to simplify deployment on most systems.
     When possible, we reactivate PIE hardening (see above).

     Also, if you set the RUSTFLAGS environment variable, the following parameters will
     be ignored.

     For more information on static builds, please refer to Rust's RFC 1721.
     https://rust-lang.github.io/rfcs/1721-crt-static.html#specifying-dynamicstatic-c-runtime-linkage
  */
  codegenOptsMap = {
    "armv6l-unknown-linux-musleabihf" = [
      "target-feature=+crt-static"
      "link-arg=-static"
    ]; # compile as dynamic with static-pie
    "aarch64-unknown-linux-musl" = [
      "target-feature=+crt-static"
      "link-arg=-static"
    ]; # segfault with static-pie
    "i686-unknown-linux-musl" = [
      "target-feature=+crt-static"
      "link-arg=-static"
    ]; # segfault with static-pie
    "x86_64-unknown-linux-musl" =
      [ "target-feature=+crt-static" "link-arg=-static-pie" ];
  };

  # NixOS and Rust/Cargo triples do not match for ARM, fix it here.
  rustTarget = if target == "armv6l-unknown-linux-musleabihf" then
    "arm-unknown-linux-musleabihf"
  else
    target;

  codegenOpts = if target != null then codegenOptsMap.${target} else [
    "link-args=-fuse-ld=mold"
  ];

  commonArgs =
    {
      inherit src;
      pname = "garage";
      version = git_version;

      strictDeps = true;
      cargoExtraArgs = "--features ${featuresStr}";

      GIT_VERSION = git_version;

      CARGO_PROFILE = if release then "release" else "dev";
      CARGO_BUILD_RUSTFLAGS =
        lib.concatStringsSep
          " "
          (builtins.map (flag: "-C ${flag}") codegenOpts);
    }
  //
    (if rustTarget != null then {
      CARGO_BUILD_TARGET = rustTarget;
    } else {});

in rec {
  inherit toolchain;

  devShell = pkgs.mkShell {
    buildInputs = [
      toolchain
    ];
  };

  garage-deps = craneLib.buildDepsOnly commonArgs;

  garage = craneLib.buildPackage (commonArgs // {
    cargoArtifacts = garage-deps;
    doCheck = false;
  });

  garage-test = craneLib.cargoTest (commonArgs // {
    cargoTestExtraArgs = "--workspace";
    cargoArtifacts = garage;
    CARGO_PROFILE = "test";
  });
}