[WIP] flake updates

flake.nix

@@ -2,73 +2,103 @@
   description = "Build a cargo project without extra checks";
 
   inputs = {
-    nixpkgs.url = "nixpkgs/nixos-23.11";
-    crane = {
-      url = "github:ipetkov/crane";
+    nixpkgs.url = "nixpkgs/nixos-unstable";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
       inputs.nixpkgs.follows = "nixpkgs";
     };
+    crane.url = "github:ipetkov/crane";
     flake-utils.url = "github:numtide/flake-utils";
   };
 
-  outputs = { self, nixpkgs, crane, flake-utils, ... }:
-    flake-utils.lib.eachDefaultSystem (system:
-      let
-        pkgs = nixpkgs.legacyPackages.${system};
+  outputs = {
+    self,
+    nixpkgs,
+    rust-overlay,
+    crane,
+    flake-utils,
+  }:
+    flake-utils.lib.eachDefaultSystem (system: let
+      pkgs = import nixpkgs {
+        inherit system;
+        overlays = [rust-overlay.overlays.default];
+      };
 
-        craneLib = crane.lib.${system};
+      msrv = "1.63.0";
+      rustVersions = with pkgs.rust-bin;
+        builtins.mapAttrs (_name: rust-bin:
+          rust-bin.override {
+            extensions = ["rust-src" "rustfmt" "llvm-tools-preview"];
+          })
+        {
+          msrv = stable.${msrv}.default;
+          stable = stable.latest.default;
+          nightly = nightly.latest.default;
+        };
+
+      craneLibVersions = builtins.mapAttrs (name: rust-bin: (crane.mkLib pkgs).overrideToolchain (_: rust-bin)) rustVersions;
+      craneLib = craneLibVersions.nightly;
 
-        nginxWithStream = pkgs.nginxMainline.overrideAttrs (oldAttrs: {
-          configureFlags = oldAttrs.configureFlags ++ [
+      nginxWithStream = pkgs.nginxMainline.overrideAttrs (oldAttrs: {
+        configureFlags =
+          oldAttrs.configureFlags
+          ++ [
             "--with-stream"
             "--with-stream_ssl_module"
             "--error-log-path=/dev/null"
           ];
-        });
+      });
 
-        ohttp-relay = craneLib.buildPackage {
-          src = pkgs.lib.cleanSourceWith {
-            src = craneLib.path ./.;
-            filter = path: type: builtins.match ".*\\.template$" path != null || craneLib.filterCargoSources path type;
-          };
-          strictDeps = true;
+      ohttp-relay = craneLib.buildPackage {
+        src = pkgs.lib.cleanSourceWith {
+          src = craneLib.path ./.;
+          filter = path: type: builtins.match ".*\\.template$" path != null || craneLib.filterCargoSources path type;
+        };
+        strictDeps = true;
 
-          buildInputs = [
+        buildInputs =
+          [
             nginxWithStream
-          ] ++ pkgs.lib.optionals pkgs.stdenv.isDarwin [
+          ]
+          ++ pkgs.lib.optionals pkgs.stdenv.isDarwin [
             pkgs.libiconv
             pkgs.darwin.apple_sdk.frameworks.Security
           ];
 
-          preBuild = ''
-            export PATH=${nginxWithStream}/bin:$PATH
-          '';
-        };
-      in
-      {
-        checks = {
-          inherit ohttp-relay;
-        };
+        preBuild = ''
+          export PATH=${nginxWithStream}/bin:$PATH
+        '';
+      };
 
-        packages.nginx-with-stream = nginxWithStream;
-        packages.default = ohttp-relay;
+      devShells = builtins.mapAttrs (_name: craneLib:
+        craneLib.devShell {
+          packages = with pkgs;
+            [
+              nginxWithStream
+              cargo-edit
+              cargo-nextest
+              cargo-watch
+              rust-analyzer
+            ]
+            ++ pkgs.lib.optionals (!pkgs.stdenv.isDarwin) [
+              cargo-llvm-cov
+            ];
+        })
+      craneLibVersions;
+    in {
+      checks = {
+        inherit ohttp-relay;
+      };
 
-        apps.default = flake-utils.lib.mkApp {
-          drv = ohttp-relay;
-        };
+      packages.nginx-with-stream = nginxWithStream;
+      packages.default = ohttp-relay;
 
-        devShells.default = craneLib.devShell {
-          checks = self.checks.${system};
+      apps.default = flake-utils.lib.mkApp {
+        drv = ohttp-relay;
+      };
 
-          packages = [
-            nginxWithStream
-            pkgs.rustup
-          ];
+      devShells = devShells // {default = devShells.nightly;};
 
-          shellHook = ''
-            rustup default nightly
-            rustup component add rust-src
-            export PATH=${pkgs.rustup}/bin:$PATH
-          '';
-        };
-      });
+      formatter = pkgs.alejandra;
+    });
 }