package: Add ability to reinstall a package

- Also add ability restore missing configuration files during reinstall.

- Reinstall is useful for restoring the original configuration files of the
package.

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

actions/packages

@@ -40,6 +40,12 @@ def parse_arguments():
     subparser.add_argument(
         '--force-configuration', choices=['new', 'old'],
         help='force old/new configuration files during install')
+    subparser.add_argument(
+        '--reinstall', action='store_true',
+        help='force re-installation of package even if it is current')
+    subparser.add_argument(
+        '--force-missing-configuration', action='store_true',
+        help='force installation of missing configuration files')
     subparser.add_argument(
         'module', help='name of module for which package is being installed')
     subparser.add_argument('packages', nargs='+',
@@ -94,6 +100,12 @@ def subcommand_install(arguments):
     elif arguments.force_configuration == 'new':
         extra_arguments += ['-o', 'Dpkg::Options::=--force-confnew']
 
+    if arguments.reinstall:
+        extra_arguments.append('--reinstall')
+
+    if arguments.force_missing_configuration:
+        extra_arguments += ['-o', 'Dpkg::Options::=--force-confmiss']
+
     subprocess.run(['dpkg', '--configure', '-a'])
     with _apt_hold():
         run_apt_command(['--fix-broken', 'install'])

plinth/package.py

@@ -17,6 +17,7 @@ logger = logging.getLogger(__name__)
 
 class PackageException(Exception):
     """A package operation has failed."""
+
     def __init__(self, error_string=None, error_details=None, *args, **kwargs):
         """Store apt-get error string and details."""
         super(PackageException, self).__init__(*args, **kwargs)
@@ -32,6 +33,7 @@ class PackageException(Exception):
 
 class Transaction(object):
     """Information about an ongoing transaction."""
+
     def __init__(self, module_name, package_names):
         """Initialize transaction object.
 
@@ -52,13 +54,10 @@ class Transaction(object):
         self.percentage = 0
         self.stderr = None
 
-    def install(self, skip_recommends=False, force_configuration=None):
+    def install(self, skip_recommends=False, force_configuration=None,
+                reinstall=False, force_missing_configuration=False):
         """Run an apt-get transaction to install given packages.
 
-        FreedomBox Service (Plinth) needs to be running as root when calling
-        this. Currently, this is meant to be only during first time setup when
-        --setup is argument is passed.
-
         If force_configuration is set to 'new', dpkg options will be enabled to
         make it force overwrite (without prompts) new configuration in place of
         old configuration (with a backup). This is useful when writing
@@ -75,6 +74,13 @@ class Transaction(object):
         If force_configuration is None, no special options are passed to
         apt/dpkg for configuration file behavior.
 
+        If reinstall is True, packages will be reinstalled, even if they are
+        the latest version.
+
+        If force_missing_configuration is True, any configuration files that
+        have been removed after the first package has been installed will be
+        restored.
+
         """
         try:
             self._run_apt_command(['update'])
@@ -86,6 +92,12 @@ class Transaction(object):
                 extra_arguments.append(
                     '--force-configuration={}'.format(force_configuration))
 
+            if reinstall:
+                extra_arguments.append('--reinstall')
+
+            if force_missing_configuration:
+                extra_arguments.append('--force-missing-configuration')
+
             self._run_apt_command(['install'] + extra_arguments +
                                   [self.module_name] + self.package_names)
         except subprocess.CalledProcessError as exception:

plinth/setup.py

@@ -29,6 +29,7 @@ _force_upgrader = None
 
 class Helper(object):
     """Helper routines for modules to show progress."""
+
     def __init__(self, module_name, module):
         """Initialize the object."""
         self.module_name = module_name
@@ -90,7 +91,8 @@ class Helper(object):
             self.current_operation = None
 
     def install(self, package_names, skip_recommends=False,
-                force_configuration=None):
+                force_configuration=None, reinstall=False,
+                force_missing_configuration=False):
         """Install a set of packages marking progress."""
         if self.allow_install is False:
             # Raise error if packages are not already installed.
@@ -109,7 +111,8 @@ class Helper(object):
             'step': 'install',
             'transaction': transaction,
         }
-        transaction.install(skip_recommends, force_configuration)
+        transaction.install(skip_recommends, force_configuration, reinstall,
+                            force_missing_configuration)
 
     def call(self, step, method, *args, **kwargs):
         """Call an arbitrary method during setup and note down its stage."""
@@ -408,9 +411,11 @@ class ForceUpgrader():
 
     class TemporaryFailure(Exception):
         """Raised when upgrade fails but can be tried again immediately."""
+
     class PermanentFailure(Exception):
         """Raised when upgrade fails and there is nothing more we wish to do.
         """
+
     def __init__(self):
         """Initialize the force upgrader."""
         if plinth.cfg.develop: