fully lazy handle load

In case of immediate handle load it would try to sync databases (or at
least to create database files), which is not possible in case if
command is run as non-ahriman user. This commit makes handle load lazy
and allows to run some commands as non-ahriman user

src/ahriman/application/handlers/setup.py

@@ -71,6 +71,8 @@ class Setup(Handler):
         Setup.configuration_create_sudo(application.repository.paths, args.build_command, architecture)
 
         application.repository.repo.init()
+        # lazy database sync
+        application.repository.pacman.handle  # pylint: disable=pointless-statement
 
     @staticmethod
     def build_command(root: Path, prefix: str, architecture: str) -> Path:
@@ -78,7 +80,7 @@ class Setup(Handler):
         generate build command name
 
         Args:
-            root(Path): root directory for the build command (must be root of the reporitory)
+            root(Path): root directory for the build command (must be root of the repository)
             prefix(str): command prefix in {prefix}-{architecture}-build
             architecture(str): repository architecture
 

src/ahriman/core/alpm/pacman.py

@@ -21,7 +21,7 @@ import shutil
 
 from pathlib import Path
 from pyalpm import DB, Handle, Package, SIG_PACKAGE, error as PyalpmError  # type: ignore
-from typing import Generator, Set
+from typing import Any, Callable, Generator, Set
 
 from ahriman.core.configuration import Configuration
 from ahriman.core.log import LazyLogging
@@ -36,6 +36,8 @@ class Pacman(LazyLogging):
         handle(Handle): pyalpm root ``Handle``
     """
 
+    handle: Handle
+
     def __init__(self, architecture: str, configuration: Configuration, *, refresh_database: int) -> None:
         """
         default constructor
@@ -46,6 +48,22 @@ class Pacman(LazyLogging):
             refresh_database(int): synchronize local cache to remote. If set to ``0``, no syncronization will be
                 enabled, if set to ``1`` - normal syncronization, if set to ``2`` - force syncronization
         """
+        self.__create_handle_fn: Callable[[], Handle] = lambda: self.__create_handle(
+            architecture, configuration, refresh_database=refresh_database)
+
+    def __create_handle(self, architecture: str, configuration: Configuration, *, refresh_database: int) -> Handle:
+        """
+        create lazy handle function
+
+        Args:
+            architecture(str): repository architecture
+            configuration(Configuration): configuration instance
+            refresh_database(int): synchronize local cache to remote. If set to ``0``, no syncronization will be
+                enabled, if set to ``1`` - normal syncronization, if set to ``2`` - force syncronization
+
+        Returns:
+            Handle: fully initialized pacman handle
+        """
         root = configuration.getpath("alpm", "root")
         pacman_root = configuration.getpath("alpm", "database")
         use_ahriman_cache = configuration.getboolean("alpm", "use_ahriman_cache")
@@ -53,20 +71,42 @@ class Pacman(LazyLogging):
         paths = configuration.repository_paths
         database_path = paths.pacman if use_ahriman_cache else pacman_root
 
-        self.handle = Handle(str(root), str(database_path))
+        handle = Handle(str(root), str(database_path))
         for repository in configuration.getlist("alpm", "repositories"):
-            database = self.database_init(repository, mirror, architecture)
-            self.database_copy(database, pacman_root, paths, use_ahriman_cache=use_ahriman_cache)
+            database = self.database_init(handle, repository, mirror, architecture)
+            self.database_copy(handle, database, pacman_root, paths, use_ahriman_cache=use_ahriman_cache)
 
         if use_ahriman_cache and refresh_database:
-            self.database_sync(refresh_database > 1)
+            self.database_sync(handle, force=refresh_database > 1)
 
-    def database_copy(self, database: DB, pacman_root: Path, paths: RepositoryPaths, *,
+        return handle
+
+    def __getattr__(self, item: str) -> Any:
+        """
+        pacman handle extractor
+
+        Args:
+            item(str): property name
+
+        Returns:
+            Any: attribute by its name
+
+        Raises:
+            AttributeError: in case if no such attribute found
+        """
+        if item == "handle":
+            handle = self.__create_handle_fn()
+            setattr(self, item, handle)
+            return handle
+        return super().__getattr__(item)  # required for logging attribute
+
+    def database_copy(self, handle: Handle, database: DB, pacman_root: Path, paths: RepositoryPaths, *,
                       use_ahriman_cache: bool) -> None:
         """
         copy database from the operating system root to the ahriman local home
 
         Args:
+            handle(Handle): pacman handle which will be used for database copying
             database(DB): pacman database instance to be copied
             pacman_root(Path): operating system pacman root
             paths(RepositoryPaths): repository paths instance
@@ -78,7 +118,7 @@ class Pacman(LazyLogging):
         if not use_ahriman_cache:
             return
         # copy root database if no local copy found
-        pacman_db_path = Path(self.handle.dbpath)
+        pacman_db_path = Path(handle.dbpath)
         if not pacman_db_path.is_dir():
             return  # root directory does not exist yet
         dst = repository_database(pacman_db_path)
@@ -92,11 +132,12 @@ class Pacman(LazyLogging):
         shutil.copy(src, dst)
         paths.chown(dst)
 
-    def database_init(self, repository: str, mirror: str, architecture: str) -> DB:
+    def database_init(self, handle: Handle, repository: str, mirror: str, architecture: str) -> DB:
         """
         create database instance from pacman handler and set its properties
 
         Args:
+            handle(Handle): pacman handle which will be used for database initializing
             repository(str): pacman repository name (e.g. core)
             mirror(str): arch linux mirror url
             architecture(str): repository architecture
@@ -104,21 +145,23 @@ class Pacman(LazyLogging):
         Returns:
             DB: loaded pacman database instance
         """
-        database: DB = self.handle.register_syncdb(repository, SIG_PACKAGE)
+        self.logger.info("loading pacman databases")
+        database: DB = handle.register_syncdb(repository, SIG_PACKAGE)
         # replace variables in mirror address
         database.servers = [mirror.replace("$repo", repository).replace("$arch", architecture)]
         return database
 
-    def database_sync(self, force: bool) -> None:
+    def database_sync(self, handle: Handle, *, force: bool) -> None:
         """
         sync local database
 
         Args:
+            handle(Handle): pacman handle which will be used for database sync
             force(bool): force database syncronization (same as ``pacman -Syy``)
         """
         self.logger.info("refresh ahriman's home pacman database (force refresh %s)", force)
-        transaction = self.handle.init_transaction()
-        for database in self.handle.get_syncdbs():
+        transaction = handle.init_transaction()
+        for database in handle.get_syncdbs():
             try:
                 database.update(force)
             except PyalpmError: