[PATCH v2 1/2] Add flakes support

[Valentin Kharin <valentin.kharin@unikie.com>]

Signed-off-by: Valentin Kharin <valentin.kharin@unikie.com>
---
 flake.lock         | 43 ++++++++++++++++++++++++++++++++
 flake.lock.license |  3 +++
 flake.nix          | 62 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 108 insertions(+)
 create mode 100644 flake.lock
 create mode 100644 flake.lock.license
 create mode 100644 flake.nix

diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..aa4ee5e
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,43 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "locked": {
+        "lastModified": 1667395993,
+        "narHash": "sha256-nuEHfE/LcWyuSWnS8t12N1wc105Qtau+/OdUAjtQ0rA=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "5aed5285a952e0b949eb3ba02c12fa4fcfef535f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1669635185,
+        "narHash": "sha256-vYg6GjnsEWNWt/4TmfFN9WtQmSXb4S796J2UOfyTcW0=",
+        "ref": "refs/heads/rootfs",
+        "rev": "3176ddef4b4cec85faa2f49d29ce74816d452dc0",
+        "revCount": 429673,
+        "type": "git",
+        "url": "https://spectrum-os.org/git/nixpkgs/"
+      },
+      "original": {
+        "ref": "refs/heads/rootfs",
+        "type": "git",
+        "url": "https://spectrum-os.org/git/nixpkgs/"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.lock.license b/flake.lock.license
new file mode 100644
index 0000000..a8a7980
--- /dev/null
+++ b/flake.lock.license
@@ -0,0 +1,3 @@
+SPDX-License-Identifier: CC0-1.0
+SPDX-FileCopyrightText: 2022 Unikie
+
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..ab54fed
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,62 @@
+# SPDX-License-Identifier: MIT
+# SPDX-FileCopyrightText: 2022 Unikie
+
+{
+  description = "A compartmentalized operating system";
+
+  # NOTE: Revision specification format is ?ref=refs%2fheads%2f<BRANCH>&rev=<COMMIT_REVISION>
+  inputs.nixpkgs.url =
+    "git+https://spectrum-os.org/git/nixpkgs/?ref=refs%2fheads%2frootfs";
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+
+  nixConfig = {
+    extra-substituters = [ "https://cache.dataaturservice.se/spectrum/" ];
+    trusted-public-keys = [
+      "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY="
+      "spectrum-os.org-1:rnnSumz3+Dbs5uewPlwZSTP0k3g/5SRG4hD7Wbr9YuQ="
+    ];
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    let
+      supportedSystems = with flake-utils.lib.system; [ x86_64-linux aarch64-linux ];
+    in flake-utils.lib.eachSystem supportedSystems (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+        config = { inherit pkgs; };
+        lib = pkgs.lib;
+
+        mkEntryPoint = { name ? builtins.baseNameOf path, path
+          , enableShell ? true, enablePackage ? true }:
+          let
+            shell = {
+              # NOTE: https://stackoverflow.com/a/43850372
+              devShells.${name} =
+                import (path + "/shell.nix") { inherit config; };
+            };
+            package = { packages.${name} = import path { inherit config; }; };
+          in (if enableShell then shell else { })
+          // (if enablePackage then package else { });
+
+        # Entry point is a directory with shell.nix and default.nix
+        # This function maps every entry point to corresponding devShell and package
+        mapEntryPoints = epoints:
+          builtins.foldl' lib.recursiveUpdate { } (map mkEntryPoint epoints);
+      in lib.recursiveUpdate (mapEntryPoints [
+        {
+          path = ./.;
+          enablePackage = false;
+        }
+        { path = ./host/initramfs; }
+        { path = ./host/rootfs; }
+        { path = ./host/start-vm; }
+        { path = ./img/app; }
+        { path = ./release/live; }
+        { path = ./vm/sys/net; }
+      ]) {
+        # Add some other flake schema related stuff here.
+        # NOTE: flake-utils.lib.eachDefaultSystem automagically adds ${system}.
+        devShells.documentation = import ./Documentation { inherit config; };
+        packages.documentation = import ./Documentation { inherit config; };
+      });
+}
-- 
2.38.1