add daemon subcommand

This command emulates default systemd timer and can be useful in docker
container in order to run 24/7

src/ahriman/application/ahriman.py

@@ -82,6 +82,7 @@ def _parser() -> argparse.ArgumentParser:
     subparsers = parser.add_subparsers(title="command", help="command to run", dest="command", required=True)
 
     _set_aur_search_parser(subparsers)
+    _set_daemon_parser(subparsers)
     _set_help_parser(subparsers)
     _set_help_commands_unsafe_parser(subparsers)
     _set_key_import_parser(subparsers)
@@ -141,6 +142,28 @@ def _set_aur_search_parser(root: SubParserAction) -> argparse.ArgumentParser:
     return parser
 
 
+def _set_daemon_parser(root: SubParserAction) -> argparse.ArgumentParser:
+    """
+    add parser for daemon subcommand
+
+    Args:
+        root(SubParserAction): subparsers for the commands
+
+    Returns:
+        argparse.ArgumentParser: created argument parser
+    """
+    parser = root.add_parser("daemon", help="run application as daemon",
+                             description="start process which periodically will run update process",
+                             formatter_class=_formatter)
+    parser.add_argument("-i", "--interval", help="interval between runs in seconds", type=int, default=60 * 60 * 12)
+    parser.add_argument("--no-aur", help="do not check for AUR updates. Implies --no-vcs", action="store_true")
+    parser.add_argument("--no-local", help="do not check local packages for updates", action="store_true")
+    parser.add_argument("--no-manual", help="do not include manual updates", action="store_true")
+    parser.add_argument("--no-vcs", help="do not check VCS packages", action="store_true")
+    parser.set_defaults(handler=handlers.Daemon, dry_run=False, exit_code=False, package=[])
+    return parser
+
+
 def _set_help_parser(root: SubParserAction) -> argparse.ArgumentParser:
     """
     add parser for listing help subcommand

src/ahriman/application/handlers/__init__.py

@@ -22,6 +22,7 @@ from ahriman.application.handlers.handler import Handler
 from ahriman.application.handlers.add import Add
 from ahriman.application.handlers.backup import Backup
 from ahriman.application.handlers.clean import Clean
+from ahriman.application.handlers.daemon import Daemon
 from ahriman.application.handlers.dump import Dump
 from ahriman.application.handlers.help import Help
 from ahriman.application.handlers.key_import import KeyImport

src/ahriman/application/handlers/daemon.py

@@ -0,0 +1,51 @@
+#
+# Copyright (c) 2021-2022 ahriman team.
+#
+# This file is part of ahriman
+# (see https://github.com/arcan1s/ahriman).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+import argparse
+import threading
+
+from typing import Type
+
+from ahriman.application.handlers import Handler
+from ahriman.core.configuration import Configuration
+
+
+class Daemon(Handler):
+    """
+    daemon packages handler
+    """
+
+    @classmethod
+    def run(cls: Type[Handler], args: argparse.Namespace, architecture: str,
+            configuration: Configuration, no_report: bool, unsafe: bool) -> None:
+        """
+        callback for command line
+
+        Args:
+            args(argparse.Namespace): command line args
+            architecture(str): repository architecture
+            configuration(Configuration): configuration instance
+            no_report(bool): force disable reporting
+            unsafe(bool): if set no user check will be performed before path creation
+        """
+        from ahriman.application.handlers import Update
+        Update.run(args, architecture, configuration, no_report, unsafe)
+        timer = threading.Timer(args.interval, Daemon.run, (args, architecture, configuration, no_report, unsafe))
+        timer.start()
+        timer.join()

tests/ahriman/application/handlers/test_handler_daemon.py

@@ -0,0 +1,40 @@
+import argparse
+
+from pytest_mock import MockerFixture
+
+from ahriman.application.handlers import Daemon
+from ahriman.core.configuration import Configuration
+
+
+def _default_args(args: argparse.Namespace) -> argparse.Namespace:
+    """
+    default arguments for these test cases
+
+    Args:
+        args(argparse.Namespace): command line arguments fixture
+
+    Returns:
+        argparse.Namespace: generated arguments for these test cases
+    """
+    args.interval = 60 * 60 * 12
+    args.no_aur = False
+    args.no_local = False
+    args.no_manual = False
+    args.no_vcs = False
+    return args
+
+
+def test_run(args: argparse.Namespace, configuration: Configuration, mocker: MockerFixture) -> None:
+    """
+    must run command
+    """
+    args = _default_args(args)
+    run_mock = mocker.patch("ahriman.application.handlers.Update.run")
+    start_mock = mocker.patch("threading.Timer.start")
+    join_mock = mocker.patch("threading.Timer.join")
+
+    Daemon.run(args, "x86_64", configuration, True, False)
+    Daemon._SHOULD_RUN = False
+    run_mock.assert_called_once_with(args, "x86_64", configuration, True, False)
+    start_mock.assert_called_once_with()
+    join_mock.assert_called_once_with()

tests/ahriman/application/test_ahriman.py

@@ -65,6 +65,26 @@ def test_subparsers_aur_search_architecture(parser: argparse.ArgumentParser) ->
     assert args.architecture == [""]
 
 
+def test_subparsers_daemon(parser: argparse.ArgumentParser) -> None:
+    """
+    daemon command must imply dry run, exit code and package
+    """
+    args = parser.parse_args(["daemon"])
+    assert not args.dry_run
+    assert not args.exit_code
+    assert args.package == []
+
+
+def test_subparsers_daemon_option_interval(parser: argparse.ArgumentParser) -> None:
+    """
+    daemon command must convert interval option to int instance
+    """
+    args = parser.parse_args(["daemon"])
+    assert isinstance(args.interval, int)
+    args = parser.parse_args(["daemon", "--interval", "10"])
+    assert isinstance(args.interval, int)
+
+
 def test_subparsers_help(parser: argparse.ArgumentParser) -> None:
     """
     help command must imply architecture list, lock, no-report, quiet, unsafe and parser