package: Implement low-level methods for uninstalling

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

actions/packages

@@ -51,6 +51,8 @@ def parse_arguments():
                            help='list of packages to install')
 
     subparser = subparsers.add_parser('remove', help='remove the package(s)')
+    subparser.add_argument(
+        'app_id', help='ID of app for which package is being uninstalled')
     subparser.add_argument('--packages', required=True,
                            help='List of packages to remove', nargs='+')
 
@@ -107,8 +109,19 @@ def subcommand_install(arguments):
 
 
 def subcommand_remove(arguments):
-    """Remove apt package(s)."""
-    sys.exit(run_apt_command(['remove'] + arguments.packages))
+    """Remove packages using apt-get."""
+    try:
+        _assert_managed_packages(arguments.app_id, arguments.packages)
+    except Exception as exception:
+        print('Access check failed:', exception, file=sys.stderr)
+        sys.exit(99)
+
+    subprocess.run(['dpkg', '--configure', '-a'], check=False)
+    with apt_hold_freedombox():
+        run_apt_command(['--fix-broken', 'install'])
+        returncode = run_apt_command(['remove'] + arguments.packages)
+
+    sys.exit(returncode)
 
 
 def _assert_managed_packages(app_id, packages):
@@ -118,7 +131,7 @@ def _assert_managed_packages(app_id, packages):
     app = app_module.App.get(app_id)
     managed_packages = []
     for component in app.get_components_of_type(Packages):
-        managed_packages += component.possible_packages
+        managed_packages += component.possible_packages + component.conflicts
 
     for package in packages:
         assert package in managed_packages

plinth/modules/email/__init__.py

@@ -16,7 +16,7 @@ from plinth.modules.backups.components import BackupRestore
 from plinth.modules.config import get_domainname
 from plinth.modules.firewall.components import Firewall
 from plinth.modules.letsencrypt.components import LetsEncrypt
-from plinth.package import Packages, remove
+from plinth.package import Packages, uninstall
 from plinth.signals import domain_added, domain_removed
 from plinth.utils import format_lazy
 
@@ -173,7 +173,7 @@ class EmailApp(plinth.app.App):
             if packages_to_remove:
                 logger.info('Removing conflicting packages: %s',
                             packages_to_remove)
-                remove(packages_to_remove)
+                uninstall(packages_to_remove)
 
         # Install
         _clear_conflicts()

plinth/package.py

@@ -17,7 +17,7 @@ from django.utils.translation import gettext as _
 from django.utils.translation import gettext_lazy
 
 from plinth import actions, app
-from plinth.errors import ActionError, MissingPackageError
+from plinth.errors import MissingPackageError
 from plinth.utils import format_lazy
 
 from . import operation as operation_module
@@ -144,7 +144,7 @@ class Packages(app.FollowerComponent):
                 self._packages.append(package)
 
         self.skip_recommends = skip_recommends
-        self.conflicts = conflicts
+        self.conflicts = conflicts or []
         self.conflicts_action = conflicts_action
 
     @property
@@ -324,6 +324,15 @@ class Transaction:
             logger.exception('Error installing package: %s', exception)
             raise
 
+    def uninstall(self):
+        """Run an apt-get transaction to uninstall given packages."""
+        try:
+            self._run_apt_command(['remove', self.app_id, '--packages'] +
+                                  self.package_names)
+        except subprocess.CalledProcessError as exception:
+            logger.exception('Error uninstalling package: %s', exception)
+            raise
+
     def refresh_package_lists(self):
         """Refresh apt package lists."""
         try:
@@ -351,7 +360,7 @@ class Transaction:
 
         return_code = process.wait()
         if return_code != 0:
-            raise PackageException(_('Error during installation'), self.stderr)
+            raise PackageException(_('Error running apt-get'), self.stderr)
 
     def _read_stdout(self, process):
         """Read the stdout of the process and update progress."""
@@ -421,6 +430,30 @@ def install(package_names, skip_recommends=False, force_configuration=None,
                         force_missing_configuration)
 
 
+def uninstall(package_names):
+    """Uninstall a set of packages."""
+    try:
+        operation = operation_module.Operation.get_operation()
+    except AttributeError:
+        raise RuntimeError(
+            'uninstall() must be called from within an operation.')
+
+    start_time = time.time()
+    while is_package_manager_busy():
+        if time.time() - start_time >= 24 * 3600:  # One day
+            raise PackageException(_('Timeout waiting for package manager'))
+
+        time.sleep(3)  # seconds
+
+    logger.info('Running uninstall for app - %s, packages - %s',
+                operation.app_id, package_names)
+
+    from . import package
+    transaction = package.Transaction(operation.app_id, package_names)
+    operation.thread_data['transaction'] = transaction
+    transaction.uninstall()
+
+
 def is_package_manager_busy():
     """Return whether a package manager is running."""
     try:
@@ -467,11 +500,3 @@ def packages_installed(candidates: Union[list, tuple]) -> list:
             pass
 
     return installed_packages
-
-
-def remove(packages: Union[list, tuple]) -> None:
-    """Remove packages."""
-    try:
-        actions.superuser_run('packages', ['remove', '--packages'] + packages)
-    except ActionError:
-        pass

plinth/tests/test_package.py

@@ -9,8 +9,8 @@ from unittest.mock import Mock, call, patch
 import pytest
 
 from plinth.app import App
-from plinth.errors import ActionError, MissingPackageError
-from plinth.package import Package, Packages, packages_installed, remove
+from plinth.errors import MissingPackageError
+from plinth.package import Package, Packages, packages_installed
 
 
 class TestPackageExpressions(unittest.TestCase):
@@ -54,7 +54,7 @@ def test_packages_init():
     assert component.possible_packages == ['foo', 'bar']
     assert component.component_id == 'test-component'
     assert not component.skip_recommends
-    assert component.conflicts is None
+    assert component.conflicts == []
     assert component.conflicts_action is None
 
     with pytest.raises(ValueError):
@@ -189,17 +189,3 @@ def test_packages_installed():
     assert len(packages_installed(())) == 0
     assert len(packages_installed(('unknown-package', ))) == 0
     assert len(packages_installed(('python3', ))) == 1
-
-
-@patch('plinth.actions.superuser_run')
-def test_remove(run):
-    """Test removing packages."""
-    remove(['package1', 'package2'])
-    run.assert_has_calls(
-        [call('packages', ['remove', '--packages', 'package1', 'package2'])])
-
-    run.reset_mock()
-    run.side_effect = ActionError()
-    remove(['package1'])
-    run.assert_has_calls(
-        [call('packages', ['remove', '--packages', 'package1'])])