From e53634976cd873c57def88399929e88636539043 Mon Sep 17 00:00:00 2001
From: Bruno BELANYI <bruno@belanyi.fr>
Date: Mon, 22 Aug 2022 17:09:07 +0200
Subject: [PATCH] nix: init flake environment

---
 flake.lock | 116 ++++++++++++++++++++++++++++++++++++++++
 flake.nix  | 152 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 268 insertions(+)
 create mode 100644 flake.lock
 create mode 100644 flake.nix

diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..0c438ed
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,116 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "locked": {
+        "lastModified": 1659877975,
+        "narHash": "sha256-zllb8aq3YO3h8B/U0/J1WBgAL8EX5yWf5pMj3G0NAmc=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "c0e246b9b83f637f4681389ecabcb2681b4f3af0",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "ref": "master",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "naersk": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1659610603,
+        "narHash": "sha256-LYgASYSPYo7O71WfeUOaEUzYfzuXm8c8eavJcel+pfI=",
+        "owner": "nix-community",
+        "repo": "naersk",
+        "rev": "c6a45e4277fa58abd524681466d3450f896dc094",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "ref": "master",
+        "repo": "naersk",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1661151577,
+        "narHash": "sha256-++S0TuJtuz9IpqP8rKktWyHZKpgdyrzDFUXVY07MTRI=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "54060e816971276da05970a983487a25810c38a7",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "pre-commit-hooks": {
+      "inputs": {
+        "flake-utils": [
+          "flake-utils"
+        ],
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1660830093,
+        "narHash": "sha256-HUhx3a82C7bgp2REdGFeHJdhEAzMGCk3V8xIvfBqg1I=",
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "rev": "8cb8ea5f1c7bc2984f460587fddd5f2e558f6eb8",
+        "type": "github"
+      },
+      "original": {
+        "owner": "cachix",
+        "ref": "master",
+        "repo": "pre-commit-hooks.nix",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "naersk": "naersk",
+        "nixpkgs": "nixpkgs",
+        "pre-commit-hooks": "pre-commit-hooks",
+        "rust-overlay": "rust-overlay"
+      }
+    },
+    "rust-overlay": {
+      "inputs": {
+        "flake-utils": [
+          "flake-utils"
+        ],
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1661136859,
+        "narHash": "sha256-o3y1elFGRs/9kqaIeziAnTy9lIWA6VHtQfq0ARRVO2A=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "6d1418192be90968acfa25e7d7b089e246eb15c4",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "ref": "master",
+        "repo": "rust-overlay",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..c36863d
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,152 @@
+{
+  description = "A simple payment processor";
+
+  inputs = {
+    flake-utils = {
+      type = "github";
+      owner = "numtide";
+      repo = "flake-utils";
+      ref = "master";
+    };
+
+    naersk = {
+      type = "github";
+      owner = "nix-community";
+      repo = "naersk";
+      ref = "master";
+      inputs = {
+        nixpkgs.follows = "nixpkgs";
+      };
+    };
+
+    nixpkgs = {
+      type = "github";
+      owner = "NixOS";
+      repo = "nixpkgs";
+      ref = "nixpkgs-unstable";
+    };
+
+    pre-commit-hooks = {
+      type = "github";
+      owner = "cachix";
+      repo = "pre-commit-hooks.nix";
+      ref = "master";
+      inputs = {
+        flake-utils.follows = "flake-utils";
+        nixpkgs.follows = "nixpkgs";
+      };
+    };
+
+    rust-overlay = {
+      type = "github";
+      owner = "oxalica";
+      repo = "rust-overlay";
+      ref = "master";
+      inputs = {
+        flake-utils.follows = "flake-utils";
+        nixpkgs.follows = "nixpkgs";
+      };
+    };
+  };
+
+  outputs =
+    { self
+    , flake-utils
+    , naersk
+    , nixpkgs
+    , pre-commit-hooks
+    , rust-overlay
+    }:
+    let
+      inherit (flake-utils.lib) eachSystem system;
+
+      mySystems = [
+        system.aarch64-linux
+        system.x86_64-darwin
+        system.x86_64-linux
+      ];
+
+      eachMySystem = eachSystem mySystems;
+    in
+    eachMySystem (system:
+    let
+      overlays = [ (import rust-overlay) ];
+      pkgs = import nixpkgs { inherit overlays system; };
+      my-rust = pkgs.rust-bin.stable.latest.default.override {
+        extensions = [ "rust-src" ];
+      };
+      naersk-lib = naersk.lib."${system}".override {
+        cargo = my-rust;
+        rustc = my-rust;
+      };
+      inherit (pkgs) lib;
+      pre-commit =
+        let
+          # See https://github.com/cachix/pre-commit-hooks.nix/issues/126
+          rust-env = pkgs.buildEnv {
+            name = "rust-env";
+            buildInputs = [ pkgs.makeWrapper ];
+            paths = [ my-rust ];
+            pathsToLink = [ "/" "/bin" ];
+            postBuild = ''
+              for i in $out/bin/*; do
+                wrapProgram "$i" --prefix PATH : "$out/bin"
+              done
+            '';
+          };
+        in
+        pre-commit-hooks.lib.${system}.run {
+          src = self;
+
+          hooks = {
+            clippy = {
+              enable = true;
+              entry = lib.mkForce "${rust-env}/bin/cargo-clippy clippy";
+            };
+
+            nixpkgs-fmt = {
+              enable = true;
+            };
+
+            rustfmt = {
+              enable = true;
+              entry = lib.mkForce "${rust-env}/bin/cargo-fmt fmt -- --check --color always";
+            };
+          };
+        };
+    in
+    rec {
+
+      devShells = {
+        default = pkgs.mkShell {
+          inputsFrom = [
+            packages.processor
+          ];
+
+          nativeBuildInputs = with pkgs; [
+            rust-analyzer
+            # Clippy, rustfmt, etc...
+            my-rust
+          ];
+
+          inherit (pre-commit) shellHook;
+
+          RUST_SRC_PATH = "${my-rust}/lib/rustlib/src/rust/library";
+        };
+      };
+
+      packages = {
+        default = self.packages."${system}".processor;
+
+        processor = naersk-lib.buildPackage {
+          src = self;
+
+          doCheck = true;
+
+          passthru = {
+            inherit my-rust;
+          };
+        };
+      };
+    });
+}