tools: add get_apps_repo.py, a lib that allows to pass --apps-repo or --apps-dir to tools or the env var YNH_APPS_DIR

tools/appslib/get_apps_repo.py

@@ -0,0 +1,58 @@
+#!/usr/bin/env python3
+
+import os
+import argparse
+import tempfile
+import logging
+from pathlib import Path
+from git import Repo
+
+
+DEFAULT_GIT_REPO = "git@github.com:YunoHost/apps"
+
+
+class TemporaryPath(Path):
+    """ Just a helper to return agnostically a Path or a TemporaryDirectory """
+    def __init__(self, *args, **kwargs):
+        self.temporary_directory = tempfile.TemporaryDirectory(*args, **kwargs)
+        Path.__init__(self, self.temporary_directory.name)
+
+    def with_segments(self, *pathsegments):
+        """ We need to overload this method because it calls type(self)
+            but we don't want to create multiple TemporaryPaths.
+        """
+        return Path(*pathsegments)
+
+
+APPS_REPO_DIR: TemporaryPath | None = None
+
+def add_args(parser: argparse.ArgumentParser, required: bool = True, allow_temp: bool = True) -> None:
+    env_apps_dir_str = os.environ.get("YNH_APPS_DIR")
+    env_apps_dir = Path(env_apps_dir_str) if env_apps_dir_str is not None else None
+
+    repo_group = parser.add_mutually_exclusive_group(required=required)
+    if allow_temp:
+        repo_group.add_argument("-c", "--apps-repo", type=str, default=DEFAULT_GIT_REPO,
+                                help="Git url to clone the 'apps' repository")
+    repo_group.add_argument("-d", "--apps-dir", type=Path, help="Path to an existing 'apps' repository", default=env_apps_dir)
+
+
+def from_args(args: argparse.Namespace | None) -> Path:
+    global APPS_REPO_DIR
+    if APPS_REPO_DIR is not None:
+        return APPS_REPO_DIR
+
+    assert args is not None
+    if args.apps_dir is not None:
+        APPS_REPO_DIR = args.apps_dir
+        return APPS_REPO_DIR
+
+    if args.apps_repo is not None:
+        tmpdir = TemporaryPath(prefix="yunohost_apps_")
+        logging.info("Cloning the 'apps' repository...")
+        repo = Repo.clone_from(args.apps_repo, to_path=tmpdir)
+        assert repo.working_tree_dir is not None
+        APPS_REPO_DIR = tmpdir
+        return APPS_REPO_DIR
+
+    raise RuntimeError("You need to pass either --apps-repo or --apps-dir!")