webui: implement /api/machines/{name}/schema

lib/jsonschema/default.nix

@@ -1,4 +1,4 @@
-{ lib ? (import <nixpkgs> { }).lib }:
+{ lib ? import <nixpkgs/lib> }:
 let
 
   # from nixos type to jsonschema type

pkgs/clan-cli/clan_cli/config/machine.py

@@ -0,0 +1,47 @@
+import json
+import subprocess
+import sys
+from pathlib import Path
+from typing import Optional
+
+from ..dirs import get_clan_flake_toplevel
+
+
+def schema_for_machine(machine_name: str, flake: Optional[Path] = None) -> dict:
+    if flake is None:
+        flake = get_clan_flake_toplevel()
+    # use nix eval to read from .#clanModules.<module_name>.options
+    proc = subprocess.run(
+        [
+            "nix",
+            "eval",
+            "--json",
+            "--impure",
+            "--show-trace",
+            "--extra-experimental-features",
+            "nix-command flakes",
+            "--expr",
+            f"""
+            let
+                flake = builtins.getFlake (toString {flake});
+                lib = flake.inputs.nixpkgs.lib;
+                module = builtins.trace (builtins.attrNames flake) flake.clanModules.machine-{machine_name};
+                evaled = lib.evalModules {{
+                    modules = [module];
+                }};
+                clanOptions = evaled.options.clan;
+                jsonschemaLib = import {Path(__file__).parent / "jsonschema"} {{ inherit lib; }};
+                jsonschema = jsonschemaLib.parseOptions clanOptions;
+            in
+                jsonschema
+            """,
+        ],
+        capture_output=True,
+        text=True,
+    )
+    if proc.returncode != 0:
+        print(proc.stderr, file=sys.stderr)
+        raise Exception(
+            f"Failed to read schema for machine {machine_name}:\n{proc.stderr}"
+        )
+    return json.loads(proc.stdout)

pkgs/clan-cli/clan_cli/webui/routers/machines.py

@@ -2,6 +2,7 @@ from typing import Annotated
 
 from fastapi import APIRouter, Body
 
+from ...config.machine import schema_for_machine
 from ...machines.create import create_machine as _create_machine
 from ...machines.list import list_machines as _list_machines
 from ..schemas import (
@@ -11,7 +12,6 @@ from ..schemas import (
     MachineCreate,
     MachineResponse,
     MachinesResponse,
-    Schema,
     SchemaResponse,
     Status,
 )
@@ -54,5 +54,5 @@ async def set_machine_config(
 
 @router.get("/api/machines/{name}/schema")
 async def get_machine_schema(name: str) -> SchemaResponse:
-    print("TODO")
+    schema = schema_for_machine(name)
-    return SchemaResponse(schema=Schema())
+    return SchemaResponse(schema=schema)

pkgs/clan-cli/clan_cli/webui/schemas.py

@@ -34,9 +34,5 @@ class ConfigResponse(BaseModel):
     config: Config
 
 
-class Schema(BaseModel):
-    pass
-
-
 class SchemaResponse(BaseModel):
-    schema_: Schema = Field(alias="schema")
+    schema_: dict = Field(alias="schema")

pkgs/clan-cli/default.nix

@@ -18,6 +18,7 @@
 , wheel
 , zerotierone
 , rsync
+, pkgs
 }:
 let
   # This provides dummy options for testing clan config and prevents it from
@@ -55,6 +56,8 @@ python3.pkgs.buildPythonPackage {
   format = "pyproject";
 
   inherit CLAN_OPTIONS_FILE;
+  # This is required for the python tests, where some nix libs depend on nixpkgs
+  CLAN_NIXPKGS = pkgs.path;
 
   nativeBuildInputs = [
     setuptools
@@ -65,6 +68,7 @@ python3.pkgs.buildPythonPackage {
   passthru.tests.clan-pytest = runCommand "clan-tests"
     {
       nativeBuildInputs = [ age zerotierone bubblewrap sops nix openssh rsync stdenv.cc ];
+      CLAN_NIXPKGS = pkgs.path;
     } ''
     export CLAN_OPTIONS_FILE="${CLAN_OPTIONS_FILE}"
     cp -r ${source} ./src

pkgs/clan-cli/shell.nix

@@ -9,7 +9,7 @@ let
     ]
   );
   checkScript = pkgs.writeScriptBin "check" ''
-    nix build .#checks.${pkgs.system}.{treefmt,clan-mypy,clan-pytest} -L "$@"
+    nix build .#checks.${pkgs.system}.{treefmt,clan-pytest} -L "$@"
   '';
 in
 pkgs.mkShell {
@@ -18,8 +18,10 @@ pkgs.mkShell {
     self.packages.${pkgs.system}.nix-unit
     pythonWithDeps
   ];
-  # sets up an editable install and add enty points to $PATH
   CLAN_FLAKE = self;
+  # This is required for the python tests, where some nix libs depend on nixpkgs
+  CLAN_NIXPKGS = pkgs.path;
+  # sets up an editable install and add enty points to $PATH
   # This provides dummy options for testing clan config and prevents it from
   # evaluating the flake .#
   CLAN_OPTIONS_FILE = ./clan_cli/config/jsonschema/options.json;

pkgs/clan-cli/tests/config/example_flake/clanModules/machine1.nix

@@ -0,0 +1,7 @@
+{ lib, ... }: {
+  options.clan.jitsi.enable = lib.mkOption {
+    type = lib.types.bool;
+    default = false;
+    description = "Enable jitsi on this machine";
+  };
+}

pkgs/clan-cli/tests/config/example_flake/flake.nix

@@ -0,0 +1,10 @@
+{
+  inputs = {
+    # this placeholder is replaced by the path to nixpkgs
+    nixpkgs.url = "__CLAN_NIXPKGS__";
+  };
+
+  outputs = _inputs: {
+    clanModules.machine-machine1 = ./clanModules/machine1.nix;
+  };
+}

pkgs/clan-cli/tests/config/test_machine_schema.py

@@ -0,0 +1,44 @@
+import os
+import tempfile
+from pathlib import Path
+from typing import Generator
+
+import pytest
+
+from clan_cli.config import machine
+
+CLAN_NIXPKGS = os.environ.get("CLAN_NIXPKGS", "")
+if CLAN_NIXPKGS == "":
+    raise Exception("CLAN_NIXPKGS not set")
+
+
+# fixture for the example flake located under ./example_flake
+# The flake is a template that is copied to a temporary location.
+# Variables like __CLAN_NIXPKGS__ are replaced with the value of the
+# CLAN_NIXPKGS environment variable.
+@pytest.fixture
+def flake_dir() -> Generator[Path, None, None]:
+    template = Path(__file__).parent / "example_flake"
+    # copy the template to a new temporary location
+    with tempfile.TemporaryDirectory() as tmpdir_:
+        tmpdir = Path(tmpdir_)
+        for path in template.glob("**/*"):
+            if path.is_dir():
+                (tmpdir / path.relative_to(template)).mkdir()
+            else:
+                (tmpdir / path.relative_to(template)).write_text(path.read_text())
+        # in the flake.nix file replace the string __CLAN_URL__ with the the clan flake
+        # provided by get_clan_flake_toplevel
+        flake_nix = tmpdir / "flake.nix"
+        flake_nix.write_text(
+            flake_nix.read_text().replace("__CLAN_NIXPKGS__", CLAN_NIXPKGS)
+        )
+        yield tmpdir
+
+
+def test_schema_for_machine(
+    flake_dir: Path, tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    monkeypatch.chdir(tmp_path)
+    schema = machine.schema_for_machine("machine1", flake_dir)
+    assert "properties" in schema