add ability to check for service updates

src/ahriman/application/ahriman.py

@@ -86,6 +86,7 @@ def _parser() -> argparse.ArgumentParser:
     _set_aur_search_parser(subparsers)
     _set_help_parser(subparsers)
     _set_help_commands_unsafe_parser(subparsers)
+    _set_help_updates_parser(subparsers)
     _set_help_version_parser(subparsers)
     _set_package_add_parser(subparsers)
     _set_package_remove_parser(subparsers)
@@ -161,8 +162,8 @@ def _set_help_parser(root: SubParserAction) -> argparse.ArgumentParser:
                              description="show help message for application or command and exit",
                              formatter_class=_formatter)
     parser.add_argument("command", help="show help message for specific command", nargs="?")
-    parser.set_defaults(handler=handlers.Help, architecture=[""], lock=None, report=False, quiet=True,
-                        unsafe=True, parser=_parser)
+    parser.set_defaults(handler=handlers.Help, architecture=[""], lock=None, report=False, quiet=True, unsafe=True,
+                        parser=_parser)
     return parser
 
 
@@ -185,6 +186,25 @@ def _set_help_commands_unsafe_parser(root: SubParserAction) -> argparse.Argument
     return parser
 
 
+def _set_help_updates_parser(root: SubParserAction) -> argparse.ArgumentParser:
+    """
+    add parser for service update check subcommand
+
+    Args:
+        root(SubParserAction): subparsers for the commands
+
+    Returns:
+        argparse.ArgumentParser: created argument parser
+    """
+    parser = root.add_parser("help-updates", help="check for service updates",
+                             description="request AUR for current version and compare with current service version",
+                             formatter_class=_formatter)
+    parser.add_argument("-e", "--exit-code", help="return non-zero exit code if updates available", action="store_true")
+    parser.set_defaults(handler=handlers.ServiceUpdates, architecture=[""], lock=None, report=False, quiet=True,
+                        unsafe=True)
+    return parser
+
+
 def _set_help_version_parser(root: SubParserAction) -> argparse.ArgumentParser:
     """
     add parser for version subcommand
@@ -197,8 +217,7 @@ def _set_help_version_parser(root: SubParserAction) -> argparse.ArgumentParser:
     """
     parser = root.add_parser("help-version", aliases=["version"], help="application version",
                              description="print application and its dependencies versions", formatter_class=_formatter)
-    parser.set_defaults(handler=handlers.Versions, architecture=[""], lock=None, report=False, quiet=True,
-                        unsafe=True)
+    parser.set_defaults(handler=handlers.Versions, architecture=[""], lock=None, report=False, quiet=True, unsafe=True)
     return parser
 
 

src/ahriman/application/handlers/__init__.py

@@ -32,6 +32,7 @@ from ahriman.application.handlers.remove import Remove
 from ahriman.application.handlers.remove_unknown import RemoveUnknown
 from ahriman.application.handlers.restore import Restore
 from ahriman.application.handlers.search import Search
+from ahriman.application.handlers.service_updates import ServiceUpdates
 from ahriman.application.handlers.setup import Setup
 from ahriman.application.handlers.shell import Shell
 from ahriman.application.handlers.sign import Sign

src/ahriman/application/handlers/service_updates.py

@@ -0,0 +1,65 @@
+#
+# Copyright (c) 2021-2023 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
+
+from typing import Type
+
+from ahriman import version
+from ahriman.application.application import Application
+from ahriman.application.handlers import Handler
+from ahriman.core.configuration import Configuration
+from ahriman.core.formatters import UpdatePrinter
+from ahriman.models.package import Package
+
+
+class ServiceUpdates(Handler):
+    """
+    service updates handler
+    """
+
+    ALLOW_AUTO_ARCHITECTURE_RUN = False  # it should be called only as "no-architecture"
+
+    @classmethod
+    def run(cls: Type[Handler], args: argparse.Namespace, architecture: str, configuration: Configuration, *,
+            report: bool, unsafe: bool) -> None:
+        """
+        callback for command line
+
+        Args:
+            args(argparse.Namespace): command line args
+            architecture(str): repository architecture
+            configuration(Configuration): configuration instance
+            report(bool): force enable or disable reporting
+            unsafe(bool): if set no user check will be performed before path creation
+        """
+        application = Application(architecture, configuration, report=report, unsafe=unsafe)
+
+        remote = Package.from_aur("ahriman", application.repository.pacman)
+        release = remote.version.rsplit("-", 1)[-1]  # we don't store pkgrel locally, so we just append it
+        local_version = f"{version.__version__}-{release}"
+
+        # technically we would like to compare versions, but it is fine to raise an exception in case if locally
+        # installed package is newer than in AUR
+        same_version = remote.version == local_version
+        if same_version:
+            return
+
+        UpdatePrinter(remote, local_version).print(verbose=True, separator=" -> ")
+        ServiceUpdates.check_if_empty(args.exit_code, not same_version)