nix flakes

.github/workflows/python-app.yml

@@ -10,10 +10,8 @@ on:
     branches: [ main ]
 
 jobs:
-  build:
-
+  check-poetry:
     runs-on: ubuntu-latest
-
     steps:
     - uses: actions/checkout@v3
     - name: Install poetry
@@ -26,8 +24,25 @@ jobs:
     - name: Install dependencies
       run: |
         sudo apt-get update
-        sudo apt-get install liblzo2-dev libsystemd-dev
+        sudo apt-get install liblzo2-dev
         poetry install
     - name: Test with pytest
       run: |
         poetry run pytest
+
+  check-nix:
+    runs-on: ubuntu-latest
+    steps:
+      - name: git checkout
+        uses: actions/checkout@v3
+      - name: Install Nix
+        uses: DeterminateSystems/nix-installer-action@main
+      - uses: DeterminateSystems/magic-nix-cache-action@main
+      - name: Check Nixpkgs inputs
+        uses: DeterminateSystems/flake-checker-action@main
+        with:
+          fail-mode: true
+
+      - name: check flake
+        run: |
+          nix flake check -L

.gitignore

@@ -29,3 +29,4 @@ tags
 vagrant/.vagrant
 .pytest_cache
 share/
+/venv

README.txt

@@ -173,10 +173,10 @@ Backy has switched to using `poetry` to manage its dependencies. This means
 that you can use `poetry install` to install dependencies from PyPI.
 
 If you don't have `backy` in your PATH when developing, enter the poetry
-virtualenv with `poetry shell` or if you're using nix with `nix-shell`.
+virtualenv with `poetry shell` or if you're using nix with `nix develop`.
 
 You can build backy with `poetry build` making a wheel and a tar archive
-in the `dist` directory, or by running `nix-build`.
+in the `dist` directory, or by running `nix build`.
 
 Authors
 =======

changelog.d/20230825_181711_jb_feature_nix_flake.rst

@@ -0,0 +1 @@
+- Add nix flake support

default.nix

@@ -1,14 +1,10 @@
-{
-  pkgs ? import <nixpkgs> {},
-  poetry2nix ? pkgs.poetry2nix,
-  lzo ? pkgs.lzo,
-  ...
-}:
-poetry2nix.mkPoetryApplication {
-    projectDir = ./.;
-    overrides = poetry2nix.overrides.withDefaults (self: super: {
-      python-lzo = super.python-lzo.overrideAttrs (old: {
-        buildInputs = [ lzo ];
-      });
-    });
-}
+(import
+  (
+    let lock = builtins.fromJSON (builtins.readFile ./flake.lock); in
+    fetchTarball {
+      url = "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
+      sha256 = lock.nodes.flake-compat.locked.narHash;
+    }
+  )
+  { src = ./.; }
+).defaultNix

flake.nix

@@ -0,0 +1,70 @@
+{
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+  inputs.flake-compat = {
+    url = "github:edolstra/flake-compat";
+    flake = false;
+  };
+
+  outputs = { self, nixpkgs, ... }:
+    let
+      supportedSystems = [ "x86_64-linux" "x86_64-darwin" "aarch64-linux" "aarch64-darwin" ];
+      forAllSystems = nixpkgs.lib.genAttrs supportedSystems;
+      pkgs = forAllSystems (system: nixpkgs.legacyPackages.${system});
+      poetryOverrides = pkgs: [
+        # https://github.com/nix-community/poetry2nix/pull/899#issuecomment-1620306977
+        pkgs.poetry2nix.defaultPoetryOverrides
+        (self: super: {
+          python-lzo = super.python-lzo.overrideAttrs (old: {
+            buildInputs = (old.buildInputs or []) ++ [ pkgs.lzo ];
+          });
+          scriv = super.scriv.overrideAttrs (old: {
+            buildInputs = (old.buildInputs or []) ++ [ super.setuptools ];
+          });
+          consulate-fc-nix-test = super.consulate-fc-nix-test.overrideAttrs (old: {
+            buildInputs = (old.buildInputs or []) ++ [ super.setuptools super.setuptools-scm ];
+          });
+        })
+      ];
+      poetryEnv = pkgs: pkgs.poetry2nix.mkPoetryEnv {
+        projectDir = self;
+        python = pkgs.python310;
+        overrides = poetryOverrides pkgs;
+        editablePackageSources = {
+          backy = ./src;
+        };
+      };
+    in
+    {
+      packages = forAllSystems (system: {
+        default = pkgs.${system}.poetry2nix.mkPoetryApplication {
+          projectDir = self;
+          doCheck = true;
+          python = pkgs.${system}.python310;
+          overrides = poetryOverrides pkgs.${system};
+        };
+
+        venv = poetryEnv pkgs.${system};
+      });
+
+      devShells = forAllSystems (system: {
+        default = pkgs.${system}.mkShellNoCC {
+          BACKY_CMD = "backy";
+          packages = with pkgs.${system}; [
+            (poetryEnv pkgs.${system})
+            poetry
+          ];
+        };
+      });
+
+      checks = forAllSystems (system: {
+        pytest = pkgs.${system}.runCommand "pytest" {
+          nativeBuildInputs = [ (poetryEnv pkgs.${system}) ];
+        } ''
+          export BACKY_CMD=backy
+          cd ${self}
+          pytest -vv -p no:cacheprovider --no-cov
+          touch $out
+        '';
+      });
+    };
+}

shell.nix

@@ -1,17 +1,10 @@
-{
-  pkgs ? import <nixpkgs> {},
-  ...
-}:
-pkgs.mkShell {
-  buildInputs = [ pkgs.lzo ];
-  packages = [ pkgs.poetry ];
-  shellHook = ''
-    # check if `poetry env info --path`/bin/activate exists
-    POETRY_ENV_PATH=$(poetry env info --path)/bin/activate
-    if [ -f $POETRY_ENV_PATH ]; then
-      source $POETRY_ENV_PATH
-    else
-      echo "Run \`poetry install\` to install dependencies first"
-    fi
-  '';
-}
+(import
+  (
+    let lock = builtins.fromJSON (builtins.readFile ./flake.lock); in
+    fetchTarball {
+      url = "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
+      sha256 = lock.nodes.flake-compat.locked.narHash;
+    }
+  )
+  { src = ./.; }
+).shellNix

smoketest.sh

@@ -3,10 +3,13 @@
 set -e
 umask 022
 
-source `poetry env info --path`/bin/activate
+if [[ -z "$BACKY_CMD" ]]; then
+  echo "error: BACKY_CMD is not set. Set it manually or call via pytest"
+  exit 2
+fi
 
 BACKUP=$(mktemp -d -t backy.test.XXXXX)
-BACKY="backy -l ${BACKUP}/backy.log"
+BACKY="$BACKY_CMD -l ${BACKUP}/backy.log"
 export TZ=Europe/Berlin
 
 mkdir ${BACKUP}/backup
@@ -40,7 +43,7 @@ $BACKY backup manual:test
 echo "Done."
 
 echo -n "Backing up img_state1.img with unknown tag. "
-! $BACKY backup unknown
+$BACKY backup unknown && exit 1
 echo "Done."
 
 echo -n "Restoring img_state1.img from level 0. "

src/backy/conftest.py

@@ -18,9 +18,10 @@
 
 @pytest.fixture(autouse=True, scope="session")
 def fix_pytest_coverage_465():
-    os.environ["COV_CORE_SOURCE"] = os.path.abspath(
-        os.environ["COV_CORE_SOURCE"]
-    )
+    if "COV_CORE_SOURCE" in os.environ:
+        os.environ["COV_CORE_SOURCE"] = os.path.abspath(
+            os.environ["COV_CORE_SOURCE"]
+        )
 
 
 @pytest.fixture

src/backy/tests/test_backy.py

@@ -4,7 +4,7 @@
 import pytest
 
 import backy.backup
-from backy.ext_deps import BASH
+from backy.ext_deps import BACKY_CMD, BASH
 from backy.tests import Ellipsis
 
 
@@ -107,7 +107,8 @@ def test_smoketest_internal(tmpdir, log):
 @pytest.mark.slow
 def test_smoketest_external():
     output = subprocess.check_output(
-        [BASH, os.path.dirname(__file__) + "/../../../smoketest.sh"]
+        [BASH, os.path.dirname(__file__) + "/../../../smoketest.sh"],
+        env=os.environ | {"BACKY_CMD": BACKY_CMD},
     )
     output = output.decode("utf-8")
     assert (