dev: implement nix flakes for developers

- Implement flakes with development dependencies
- Add a `shell.nix` that leverages edolstra/flake-compat

.gitignore

@@ -1,4 +1,3 @@
 .DS_Store
-*.nix
 *.backup
 __pycache__

flake.nix

@@ -0,0 +1,120 @@
+{
+  description = "A Nix flake for OSRD dev shell";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+    flake-compat.url = "https://flakehub.com/f/edolstra/flake-compat/1.tar.gz";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+    alejandra = {
+      url = "github:kamadorueda/alejandra/3.0.0";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+    rust-overlay,
+    flake-utils,
+    alejandra,
+    ...
+  }:
+    flake-utils.lib.eachDefaultSystem (
+      system: let
+        pkgs = import nixpkgs {
+          inherit system;
+          overlays = [rust-overlay.overlays.default];
+        };
+        pythonPackages = ps: [
+          ps.black
+          ps.isort
+          ps.flake8
+          ps.intervaltree
+          ps.numpy
+          ps.mock
+          ps.pillow
+          ps.psycopg
+          ps.psycopg2
+          ps.pyyaml
+          ps.requests
+          ps.websockets
+          (ps.callPackage (import ./nix/kdtree.nix) {})
+          (ps.callPackage (import ./nix/geojson-pydantic.nix) {inherit (ps) pydantic;})
+
+          # DATA SCIENCE
+          ps.ipykernel
+          ps.jupyterlab
+          ps.shapely
+          ps.pyproj
+          ps.ipympl
+          ps.matplotlib
+          ps.networkx
+          ps.pyosmium
+
+          ps.progress
+          ps.tqdm
+          ps.ipywidgets
+        ];
+
+        fixedNode = pkgs.nodejs-18_x;
+        fixedNodePackages = pkgs.nodePackages.override {
+          nodejs = fixedNode;
+        };
+
+        scriptFiles = builtins.attrNames (builtins.readDir ./scripts);
+        scriptBins =
+          map (
+            scriptFile:
+              pkgs.writeShellScriptBin
+              (pkgs.lib.strings.removeSuffix ".sh" scriptFile)
+              (pkgs.lib.strings.replaceStrings
+                ["#!/bin/sh"] [""]
+                (builtins.readFile ./scripts/${scriptFile}))
+          )
+          scriptFiles;
+      in
+        with pkgs; {
+          devShells.default = mkShell {
+            buildInputs =
+              [
+                # API
+                (python310.withPackages pythonPackages)
+                poetry
+
+                # EDITOAST
+                osmium-tool
+                geos
+                postgresql
+                openssl
+                pkg-config
+                rustPackages.clippy
+                cargo-watch
+                cargo-tarpaulin
+                rust-analyzer
+                rust-bin.stable.latest.default
+
+                # CORE
+                jdk17
+
+                # FRONT
+                fixedNodePackages.create-react-app
+                fixedNodePackages.eslint
+                fixedNodePackages.yarn
+                fixedNode
+
+                # Nix formatter
+                alejandra.defaultPackage.${system}
+              ]
+              ++ scriptBins;
+
+            RUST_SRC_PATH = "${rustPlatform.rustLibSrc}";
+            OSRD_DEV = "True";
+            OSRD_BACKEND_URL = "http://localhost:8080";
+          };
+        }
+    );
+}

nix/geojson-pydantic.nix

@@ -0,0 +1,24 @@
+{
+  lib,
+  buildPythonPackage,
+  fetchPypi,
+  pydantic,
+}:
+buildPythonPackage rec {
+  pname = "geojson-pydantic";
+  version = "0.3.1";
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "1clj89s39qyc510sylyx5fcfx9lpk7g8mi64rbzw067hcd5n2hk5";
+  };
+
+  doCheck = false;
+
+  propagatedBuildInputs = [pydantic];
+
+  meta = with lib; {
+    maintainers = with maintainers; [flomonster];
+    description = "GeoJson support for pydantic";
+  };
+}

nix/kdtree.nix

@@ -0,0 +1,21 @@
+{
+  lib,
+  buildPythonPackage,
+  fetchPypi,
+}:
+buildPythonPackage rec {
+  pname = "kdtree";
+  version = "0.16";
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "0d3m7pir24vp2sjg85anigv9xya4z5fh7qvlp7xf01bah73zcv9q";
+  };
+
+  doCheck = false;
+
+  meta = with lib; {
+    maintainers = with maintainers; [flomonster];
+    description = "Kdtree";
+  };
+}

shell.nix

@@ -0,0 +1,14 @@
+(
+  import
+  (
+    let
+      lock = builtins.fromJSON (builtins.readFile ./flake.lock);
+    in
+      fetchTarball {
+        url = lock.nodes.flake-compat.locked.url or "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
+        sha256 = lock.nodes.flake-compat.locked.narHash;
+      }
+  )
+  {src = ./.;}
+)
+.shellNix