allowUnfree and overlays

docs/reference/yaml-options.md

@@ -1,11 +1,14 @@
 
-| Key                        | Value                                                                         |
-| -------------------------- | ----------------------------------------------------------------------------- |
-| inputs                     | Defaults to `inputs.nixpkgs.url: github:NixOS/nixpkgs/nixpkgs-unstable`.      |
-| inputs.<name>        | Identifier name used when passing the input in your ``devenv.nix`` function.  |
-| inputs.<name>.url    | URI specification of the input, see below for possible values.                |
-| inputs.<name>.flake  | Does the input contain ``flake.nix`` or ``devenv.nix``. Defaults to ``true``. |
-| imports                    | A list of relative paths or references to inputs to import ``devenv.nix``.    |
+| Key                           | Value                                                                         |
+| ----------------------------- | ----------------------------------------------------------------------------- |
+| allowUnfree                   | Allow unfree packages. Defaults to `false`.                                   |
+| inputs                        | Defaults to `inputs.nixpkgs.url: github:NixOS/nixpkgs/nixpkgs-unstable`.      |
+| inputs.<name>           | Identifier name used when passing the input in your ``devenv.nix`` function.  |
+| inputs.<name>.url       | URI specification of the input, see below for possible values.                |
+| inputs.<name>.flake     | Does the input contain ``flake.nix`` or ``devenv.nix``. Defaults to ``true``. |
+| inputs.<name>.overlays  | A list of overlays to include from the input. |
+| imports                       | A list of relative paths or references to inputs to import ``devenv.nix``.    |
+
 
 ## inputs.<name>.url
 
@@ -24,6 +27,7 @@
 ## An extensive example
 
 ```yaml
+allowUnfree: true
 inputs:
   nixpkgs:
     url: github:NixOS/nixpkgs/nixpkgs-unstable
@@ -35,4 +39,7 @@ imports:
   - ./backend
   - myproject
   - myproject/relative/path
+overlays:
+  myproject:
+    - default
 ```

examples/overlays/devenv.nix

@@ -0,0 +1,5 @@
+{ pkgs, ... }:
+
+{
+  packages = [ pkgs.rust-bin.stable.latest.default ];
+}

examples/overlays/devenv.yaml

@@ -0,0 +1,8 @@
+allowUnfree: true
+inputs:
+  nixpkgs:
+    url: github:NixOS/nixpkgs/nixpkgs-unstable
+  rust-overlay:
+    url: github:oxalica/rust-overlay
+    overlays:
+      - default

src/devenv-yaml.nix

@@ -0,0 +1,46 @@
+{ pkgs }:
+
+pkgs.writers.writePython3Bin "devenv-yaml" { libraries = with pkgs.python3Packages; [ strictyaml path ]; } ''
+  from strictyaml import Map, MapPattern, Str, Seq
+  from strictyaml import load, Bool, Any, Optional, YAMLError
+  import json
+  import sys
+  import os
+  from path import Path
+
+  inputsSchema = MapPattern(Str(), Map({
+      "url": Str(),
+      Optional("flake", default=None): Bool(),
+      Optional("inputs", default=None): Any(),
+      Optional("overlays", default=None): Seq(Str())
+  }))
+
+  schema = Map({
+      Optional("inputs", default=None): inputsSchema,
+      Optional("allowUnfree", default=False): Bool(),
+      Optional("imports", default=None): Seq(Str())
+  })
+
+  filename = Path("devenv.yaml").bytes().decode('utf8')
+  try:
+      devenv = load(filename, schema, label="devenv.yaml").data
+  except YAMLError as error:
+      print("Error in `devenv.yaml`", error)
+      sys.exit(1)
+
+  inputs = {}
+  for input, attrs in devenv.get('inputs', {}).items():
+      inputs[input] = {k: attrs[k] for k in ('url', 'inputs', 'flake')
+                       if k in attrs}
+
+  devenv_dir = sys.argv[1]
+
+  with open(os.path.join(devenv_dir, "flake.json"), 'w') as f:
+      f.write(json.dumps(inputs))
+
+  with open(os.path.join(devenv_dir, "devenv.json"), 'w') as f:
+      f.write(json.dumps(devenv))
+
+  with open(os.path.join(devenv_dir, "imports.txt"), 'w') as f:
+      f.write("\n".join(devenv.get('imports', [])))
+''

src/devenv.nix

@@ -29,11 +29,12 @@ pkgs.writeScriptBin "devenv" ''
     export DEVENV_DIR="$(pwd)/.devenv"
     export DEVENV_GC="$DEVENV_DIR/gc"
     mkdir -p "$DEVENV_GC"
-    # TODO: validate devenv.yaml using jsonschema
     if [[ -f devenv.yaml ]]; then
-      cat devenv.yaml | ${pkgs.yaml2json}/bin/yaml2json > "$DEVENV_DIR/devenv.json"
+      ${import ./devenv-yaml.nix { inherit pkgs; }}/bin/devenv-yaml "$DEVENV_DIR"
     else
       [[ -f "$DEVENV_DIR/devenv.json" ]] && rm "$DEVENV_DIR/devenv.json"
+      [[ -f "$DEVENV_DIR/flake.json" ]] && rm "$DEVENV_DIR/flake.json"
+      [[ -f "$DEVENV_DIR/imports.txt" ]] && rm "$DEVENV_DIR/imports.txt"
     fi
     cp -f ${import ./flake.nix { inherit pkgs version; }} "$FLAKE_FILE"
     chmod +w "$FLAKE_FILE"

src/flake.nix

@@ -5,37 +5,47 @@
       pre-commit-hooks.inputs.nixpkgs.follows = "nixpkgs";
       nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
       devenv.url = "github:cachix/devenv?dir=src/modules";
-    } // (if builtins.pathExists ./.devenv/devenv.json 
-         then (builtins.fromJSON (builtins.readFile ./.devenv/devenv.json)).inputs
+    } // (if builtins.pathExists ./.devenv/flake.json 
+         then builtins.fromJSON (builtins.readFile ./.devenv/flake.json)
          else {});
 
     outputs = { nixpkgs, ... }@inputs:
       let
-        pkgs = import nixpkgs { system = "${pkgs.system}"; };
-        lib = pkgs.lib;
         devenv = if builtins.pathExists ./.devenv/devenv.json
           then builtins.fromJSON (builtins.readFile ./.devenv/devenv.json)
           else {};
-        toModule = path:
+        getOverlays = inputName: inputAttrs:
+          map (overlay: let
+              input = inputs.''${inputName} or (throw "No such input `''${inputName}` while trying to configure overlays.");
+            in input.overlays.''${overlay} or (throw "Input `''${inputName}` has no overlay called `''${overlay}`. Supported overlays: ''${nixpkgs.lib.concatStringsSep ", " (builtins.attrNames input.overlays)}"))
+            inputAttrs.overlays or [];
+        overlays = nixpkgs.lib.flatten (nixpkgs.lib.mapAttrsToList getOverlays (devenv.inputs or {}));
+        pkgs = import nixpkgs {
+          system = "${pkgs.system}";
+          allowUnfree = devenv.allowUnfree or false; 
+          inherit overlays;
+        };
+        lib = pkgs.lib;
+        importModule = path:
           if lib.hasPrefix "./" path
           then ./. + (builtins.substring 1 255 path) + "/devenv.nix"
           else if lib.hasPrefix "../" path 
-          then throw "devenv: ../ is not supported for imports"
-          else let
-            paths = lib.splitString "/" path;
-            name = builtins.head paths;
-            input = inputs.''${name} or (throw "Unknown input ''${name}");
-            subpath = "/''${lib.concatStringsSep "/" (builtins.tail paths)}";
-            devenvpath = "''${input}" + subpath + "/devenv.nix";
-            in if builtins.pathExists devenvpath
-               then devenvpath
-               else throw (devenvpath + " file does not exist for input ''${name}.");
+              then throw "devenv: ../ is not supported for imports"
+              else let
+                paths = lib.splitString "/" path;
+                name = builtins.head paths;
+                input = inputs.''${name} or (throw "Unknown input ''${name}");
+                subpath = "/''${lib.concatStringsSep "/" (builtins.tail paths)}";
+                devenvpath = "''${input}" + subpath + "/devenv.nix";
+                in if builtins.pathExists devenvpath
+                  then devenvpath
+                  else throw (devenvpath + " file does not exist for input ''${name}.");
         project = pkgs.lib.evalModules {
           specialArgs = inputs // { inherit inputs pkgs; };
           modules = [
             (inputs.devenv.modules + /top-level.nix)
             { devenv.cliVersion = "${version}"; }
-          ] ++ (map toModule (devenv.imports or [])) ++ [
+          ] ++ (map importModule (devenv.imports or [])) ++ [
             ./devenv.nix
             (devenv.devenv or {})
             (if builtins.pathExists ./devenv.local.nix then ./devenv.local.nix else {})