fix(hack): Make cachix available at compile time

crates/omnix-ci/crate.nix

@@ -39,6 +39,9 @@ in
         INSPECT_FLAKE
         NIX_SYSTEMS
         ;
+      inherit (rust-project.crates."omnix-health".crane.args)
+        CACHIX_BIN
+        ;
       DEVOUR_FLAKE = inputs.devour-flake;
 
       # This value is set in omnix-cli/crate.nix.

crates/omnix-cli/crate.nix

@@ -26,7 +26,6 @@ in
         # > error: don't yet have a `targetPackages.darwin.LibsystemCross for x86_64-apple-darwin`
         (if (stdenv.isDarwin && stdenv.isAarch64) then pkgsStatic.libiconv else pkgs.libiconv)
         pkgs.pkg-config
-        pkgs.cachix
       ];
       buildInputs = lib.optionals pkgs.stdenv.isDarwin
         (
@@ -49,6 +48,9 @@ in
       inherit (rust-project.crates."omnix-init".crane.args)
         OM_INIT_REGISTRY
         ;
+      inherit (rust-project.crates."omnix-health".crane.args)
+        CACHIX_BIN
+        ;
 
       # To avoid unnecessary rebuilds, start from cleaned source, and then add the Nix files necessary to `nix run` it. Finally, add any files required by the Rust build.
       OMNIX_SOURCE = lib.cleanSourceWith {

crates/omnix-hack/crate.nix

@@ -14,11 +14,13 @@
         IOKit
       ]
     );
-    nativeBuildInputs = [ pkgs.cachix ];
     inherit (rust-project.crates."nix_rs".crane.args)
       DEFAULT_FLAKE_SCHEMAS
       INSPECT_FLAKE
       NIX_SYSTEMS
       ;
+    inherit (rust-project.crates."omnix-health".crane.args)
+      CACHIX_BIN
+      ;
   };
 }

crates/omnix-health/crate.nix

@@ -25,6 +25,7 @@ in
         INSPECT_FLAKE
         NIX_SYSTEMS
         ;
+      CACHIX_BIN = lib.getExe pkgs.cachix;
       nativeBuildInputs = with pkgs; [
         nix # Tests need nix cli
       ];

crates/omnix-health/src/check/caches.rs

@@ -94,7 +94,7 @@ impl CachixCache {
 
     /// Run `cachix use` for this cache
     pub async fn cachix_use(&self) -> anyhow::Result<()> {
-        let mut cmd = tokio::process::Command::new("cachix");
+        let mut cmd = tokio::process::Command::new(env!("CACHIX_BIN"));
         cmd.arg("use").arg(&self.0);
         let status = cmd.spawn()?.wait().await?;
         if !status.success() {

nix/modules/flake-parts/closure-size.nix

@@ -1,7 +1,13 @@
 { ... }:
 
 let
-  maxSizeInMB = 60;
+
+  maxSize = 1000000 * maxSizeInMB.total;
+  maxSizeInMB = rec {
+    total = omnix + cachix;
+    omnix = 60;
+    cachix = 150;
+  };
 in
 {
   perSystem = { pkgs, ... }: {
@@ -13,7 +19,7 @@ in
         meta.description = "Check that omnix's nix closure size remains reasonably small";
         text = ''
           set -o pipefail
-          MAX_CLOSURE_SIZE=$(echo "${builtins.toString maxSizeInMB} * 1000000" | bc)
+          MAX_CLOSURE_SIZE=${builtins.toString maxSize}
           CLOSURE_SIZE=$(nix path-info --json -S .#default | jq '.[0]'.closureSize)
           echo "Omnix closure size: $CLOSURE_SIZE"
           echo "    Max closure size: $MAX_CLOSURE_SIZE"

nix/modules/flake-parts/devshell.nix

@@ -21,6 +21,7 @@ in
         INSPECT_FLAKE
         OMNIX_SOURCE
         OM_INIT_REGISTRY
+        CACHIX_BIN
         ;
 
       packages = with pkgs; [