nix/pkgs: add erbium

nix/pkgs/default.nix

@@ -10,4 +10,5 @@ args: {
   secretsync = import ./secretsync args;
   copybara = import ./copybara.nix args;
   hg-git = import ./hg-git.nix args;
+  erbium = import ./erbium args;
 } // (import ./heptapod-runner.nix args)

nix/pkgs/erbium/crate2nixify.nix

@@ -0,0 +1,44 @@
+{ depot, pkgs, lib, ... }:
+{ name, src, crateName ? "", depsHash, crate2nixArgs ? {} }:
+let
+  inherit (depot.third_party) crate2nix;
+  keepFiles = [ ./Cargo.toml ./Cargo.lock ];
+  deps = pkgs.stdenv.mkDerivation {
+    inherit src;
+    name = "${name}-deps";
+
+    buildInputs = [ crate2nix ];
+
+    buildPhase = ''
+      mkdir /tmp/cargo
+      export CARGO_HOME=/tmp/cargo
+
+      mkdir /tmp/gen
+      cp -R $src/* /tmp/gen
+
+      cd /tmp/gen
+      ${crate2nix}/bin/crate2nix generate
+
+      mkdir $out
+      cp /tmp/gen/Cargo.nix $out/Cargo.nix
+      cat >$out/default.nix <<EOF
+      { nixpkgs ? import <nixpkgs> {} }:
+      let cargo_nix = nixpkgs.callPackage ./Cargo.nix { inherit nixpkgs; };
+      in cargo_nix.${if crateName == "" then "rootCrate" else "workspaceMembers.${crateName}"}.build
+      EOF
+    '';
+
+    installPhase = "true";
+
+    outputHash = depsHash;
+    outputHashMode = "recursive";
+  };
+  merged = pkgs.runCommand "${name}-merged" {
+    inherit src deps;
+  } ''
+    mkdir $out
+    cp -R $src/* $out/
+    cp $deps/default.nix $deps/Cargo.nix $out/
+  '';
+in
+import merged ({ nixpkgs = pkgs; } // crate2nixArgs)

nix/pkgs/erbium/default.nix

@@ -0,0 +1,14 @@
+{ depot, pkgs, lib, ... }@args:
+let
+  crate2nixify = import ./crate2nixify.nix args;
+in
+crate2nixify {
+  name = "erbium";
+  src = pkgs.fetchFromGitHub {
+    owner = "isomer";
+    repo = "erbium";
+    rev = "39465a183454005ca96cdf7fad8638dba192f9a2";
+    hash = "sha256:10770s5bm0b0kl2q2irx78s0j5h00a8xyk1dqp9dj03vk4jbhs7q";
+  };
+  depsHash = "sha256:0vxkl8q554018x7qw0qgbp7z0mgb7jcqsrdcphv319lfxbnymzyv";
+}

third_party/default.nix

@@ -3,17 +3,25 @@
 # SPDX-License-Identifier: Apache-2.0
 
 { ... }@ch:
-let nixpkgsConfig = {
+let
+  nixpkgsConfig = {
     allowUnfree = true;
     permittedInsecurePackages = [
       "p7zip-16.02"
     ];
-}; in
-rec {
-  inherit nixpkgsConfig;
+  };
   nixpkgs = import ./nixpkgs {
     config = nixpkgsConfig;
   };
+  crate2nixSrc = nixpkgs.fetchFromGitHub {
+    owner = "kolloch";
+    repo = "crate2nix";
+    rev = "e07af104b8e41d1cd7e41dc7ac3fdcdf4953efae";
+    hash = "sha256:07syygn1rc5n1big7hf42pzgm5wc1r0mzglzvlbcb7rkzgqqhbqx";
+  };
+in
+rec {
+  inherit nixpkgsConfig nixpkgs;
   nixos = import ./nixpkgs/nixos;
   nixeval = import ./nixpkgs/nixos/lib/eval-config.nix;
   buildGo =
@@ -37,4 +45,6 @@ rec {
     };
   readTree = import ./tvl/nix/readTree {};
   gopkgs = readTree ch ./gopkgs;
+
+  crate2nix = import "${crate2nixSrc}" {};
 }