clan-cli: add git.commit_file() to auto commit files if inside a git

- commit only if inside a git repo
- commit only the specified file and nothing else
- auto-generate commit message if not specified

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

@@ -9,6 +9,7 @@ from typing import Any, Optional, Type
 
 from clan_cli.dirs import get_clan_flake_toplevel
 from clan_cli.errors import ClanError
+from clan_cli.git import commit_file
 from clan_cli.machines.folders import machine_settings_file
 from clan_cli.nix import nix_eval
 
@@ -240,6 +241,10 @@ def set_option(
     settings_file.parent.mkdir(parents=True, exist_ok=True)
     with open(settings_file, "w") as f:
         json.dump(new_config, f, indent=2)
+        if settings_file.resolve().is_relative_to(get_clan_flake_toplevel()):
+            commit_file(
+                settings_file, commit_message=f"Set option {option_description}"
+            )
 
 
 # takes a (sub)parser and configures it

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

@@ -7,6 +7,7 @@ from typing import Optional
 from fastapi import HTTPException
 
 from clan_cli.dirs import get_clan_flake_toplevel, nixpkgs_source
+from clan_cli.git import commit_file
 from clan_cli.machines.folders import machine_folder, machine_settings_file
 from clan_cli.nix import nix_eval
 
@@ -36,6 +37,7 @@ def set_config_for_machine(machine_name: str, config: dict) -> None:
     settings_path.parent.mkdir(parents=True, exist_ok=True)
     with open(settings_path, "w") as f:
         json.dump(config, f)
+    commit_file(settings_path)
 
 
 def schema_for_machine(machine_name: str, flake: Optional[Path] = None) -> dict:

pkgs/clan-cli/clan_cli/git.py

@@ -0,0 +1,51 @@
+import subprocess
+from pathlib import Path
+from typing import Optional
+
+from clan_cli.dirs import get_clan_flake_toplevel
+from clan_cli.errors import ClanError
+from clan_cli.nix import nix_shell
+
+
+# generic vcs agnostic commit function
+def commit_file(
+    file_path: Path,
+    repo_dir: Optional[Path] = None,
+    commit_message: Optional[str] = None,
+) -> None:
+    # set default for repo_dir
+    if repo_dir is None:
+        repo_dir = get_clan_flake_toplevel()
+    # check that the file is in the git repository and exists
+    if not Path(file_path).resolve().is_relative_to(repo_dir.resolve()):
+        raise ClanError(f"File {file_path} is not in the git repository {repo_dir}")
+    if not file_path.exists():
+        raise ClanError(f"File {file_path} does not exist")
+    # generate commit message if not provided
+    if commit_message is None:
+        # ensure that mentioned file path is relative to repo
+        commit_message = f"Add {file_path.relative_to(repo_dir)}"
+    # check if the repo is a git repo and commit
+    if (repo_dir / ".git").exists():
+        _commit_file_to_git(repo_dir, file_path, commit_message)
+    else:
+        return
+
+
+def _commit_file_to_git(repo_dir: Path, file_path: Path, commit_message: str) -> None:
+    """Commit a file to a git repository.
+
+    :param repo_dir: The path to the git repository.
+    :param file_path: The path to the file to commit.
+    :param commit_message: The commit message.
+    :raises ClanError: If the file is not in the git repository.
+    """
+    # add the file to the git index
+    subprocess.run(["git", "add", file_path], cwd=repo_dir, check=True)
+    # commit only that file
+    cmd = nix_shell(["git"], ["git", "commit", "-m", commit_message, file_path.name])
+    subprocess.run(
+        cmd,
+        cwd=repo_dir,
+        check=True,
+    )