Initial support for offline upgrades

https://www.freedesktop.org/software/systemd/man/latest/systemd.offline-updates.html

Resolves #45.

eopkg-offline-update.service

@@ -0,0 +1,14 @@
+[Unit]
+Description=Update the operating system whilst offline
+
+DefaultDependencies=no
+Requires=sysinit.target dbus.socket
+After=sysinit.target dbus.socket systemd-journald.socket system-update-pre.target
+Before=shutdown.target system-update.target
+
+[Service]
+Type=oneshot
+ExecStart=eopkg up --bypass-update-repo --yes-all
+StandardOutput=journal+console
+
+FailureAction=reboot

pisi/api.py

@@ -775,8 +775,33 @@ def remove_repo(name):
         raise pisi.Error(_('Repository %s does not exist. Cannot remove.')
                  % name)
 
+def is_offline_upgrade_prepared():
+    if os.path.exists('/etc/system-update') or os.path.exists('/system-update'):
+        return True
+
+    return False
+
+def clear_prepared_offline_upgrade():
+    try:
+        if os.path.exists('/etc/system-update'):
+            os.remove('/etc/system-update')
+            ctx.ui.debug(_('Deleted /etc/system-update'))
+        if os.path.exists('/system-update'):
+            os.remove('/system-update')
+            ctx.ui.debug(_('Deleted /system-update'))
+    except IOError as e:
+        ctx.ui.error(_('Failed to remove prepared offline upgrade, reason: %s') % e)
+    finally:
+        return True
+
 @locked
 def update_repos(repos, force=False):
+    if is_offline_upgrade_prepared() is True:
+        if force is True:
+            pisi.api.clear_prepared_offline_upgrade()
+        else:
+            ctx.ui.error(_('An offline upgrade is prepared for installation, blocking.'))
+
     pisi.db.historydb.HistoryDB().create_history("repoupdate")
     updated = False
     try:
@@ -788,6 +813,12 @@ def update_repos(repos, force=False):
 
 @locked
 def update_repo(repo, force=False):
+    if is_offline_upgrade_prepared() is True:
+        if force is True:
+            pisi.api.clear_prepared_offline_upgrade()
+        else:
+            ctx.ui.error(_('An offline upgrade is prepared for installation, blocking.'))
+
     pisi.db.historydb.HistoryDB().create_history("repoupdate")
     updated = __update_repo(repo, force)
     if updated:

pisi/cli/updaterepo.py

@@ -48,6 +48,14 @@ def options(self):
     def run(self):
         self.init(database = True)
 
+        if pisi.api.is_offline_upgrade_prepared() is True:
+            ctx.ui.warning(_('An offline update is already prepared'))
+            if ctx.ui.confirm(_('Do you wish to clear the previously prepared offline update?')):
+                if pisi.api.clear_prepared_offline_upgrade() is False:
+                    return
+            else:
+                return
+
         if self.args:
             repos = self.args
         else:

pisi/cli/upgrade.py

@@ -11,11 +11,14 @@
 #
 
 import optparse
+import os
+import subprocess
 
 from pisi import translate as _
 
 import pisi.cli.command as command
 import pisi.context as ctx
+import pisi.util as util
 import pisi.api
 import pisi.db
 
@@ -62,6 +65,7 @@ def options(self):
                                type="string", default=None, help=_('Name of the to be upgraded packages\' repository'))
         group.add_option("-f", "--fetch-only", action="store_true",
                      default=False, help=_("Fetch upgrades but do not install."))
+        group.add_option("--offline", action="store_true", default=False, help=_("Perform upgrades offline"))
         group.add_option("-x", "--exclude", action="append",
                      default=None, help=_("When upgrading system, ignore packages and components whose basenames match pattern."))
         group.add_option("--exclude-from", action="store",
@@ -74,11 +78,19 @@ def options(self):
 
     def run(self):
 
-        if self.options.fetch_only:
+        if self.options.fetch_only or self.options.offline:
             self.init(database=True, write=False)
         else:
             self.init()
 
+        if pisi.api.is_offline_upgrade_prepared() is True:
+            ctx.ui.warning(_('An offline update is already prepared'))
+            if ctx.ui.confirm(_('Do you wish to clear the previously prepared offline update?')):
+                if pisi.api.clear_prepared_offline_upgrade() is False:
+                    return
+            else:
+                return
+
         if not ctx.get_option('bypass_update_repo'):
             ctx.ui.info(_('Updating repositories'))
             repos = pisi.api.list_repos()
@@ -100,3 +112,9 @@ def run(self):
         packages.extend(self.args)
 
         pisi.api.upgrade(packages, repository)
+
+        if self.options.offline:
+            offline_file = os.path.join(ctx.config.history_dir(), 'prepared-offline-update')
+            if os.path.exists(offline_file):
+                if ctx.ui.confirm(_('The updates will be applied on next reboot. Do you wish to reboot now?')):
+                    subprocess.Popen(["systemctl", "soft-reboot"])

pisi/operations/upgrade.py

@@ -10,6 +10,7 @@
 # Please read the COPYING file.
 #
 
+import os
 import sys
 
 from pisi import translate as _
@@ -190,6 +191,12 @@ def upgrade(A=[], repo=None):
     if ctx.get_option('fetch_only'):
         return
 
+    # For offline upgrades return here after fetching of upgrades
+    # but prepare it first
+    if ctx.get_option('offline'):
+        prepare_offline_upgrade(order)
+        return
+
     if conflicts:
         operations.remove.remove_conflicting_packages(conflicts)
 
@@ -207,6 +214,47 @@ def upgrade(A=[], repo=None):
     finally:
         ctx.exec_usysconf()
 
+def prepare_offline_upgrade(order):
+    # https://www.freedesktop.org/software/systemd/man/latest/systemd.offline-updates.html
+    #
+    # For a high-level overview
+    # 1. Fetch upgrades with eopkg up --fetch-only
+    # 2. Create symlink to /system-update to instruct systemd to perform offline upgrades
+    # 3. Soft reboot to initiate offline upgrades
+    # 3. eopkg-offline-upgrades.service will run eopkg up --bypass-update-repo --yes-all
+    # 4. System reboots and /system-update file is removed
+
+    # a bit of a hard coded safety hack here
+    if not os.path.exists('/usr/lib/systemd/system/system-update.target.wants/eopkg-offline-update.service'):
+        ctx.ui.error(_("eopkg-offline-update.service doesn't exist, check your installation"))
+        return
+
+    # If we get to this point just unconditionally clear any previously
+    # prepared offline upgrades to avoid issues.
+    if os.path.exists('/system-update'):
+        os.remove('/system-update')
+    if os.path.exists('/etc/system-update'):
+        os.remove('/etc/system-update')
+
+    # Nothing special about this file but we need to create some sort of symlink to /system-update
+    # to instruct systemd to perform an offline update
+    offline_file = os.path.join(ctx.config.history_dir(), 'prepared-offline-update')
+
+    packagedb = pisi.db.packagedb.PackageDB()
+
+    try:
+        with open(offline_file, 'w') as f:
+            for pkg in order:
+                info = packagedb.get_package(pkg)
+                f.write("%s\n\n" % unicode(info))
+        os.symlink(offline_file, '/system-update')
+        ctx.ui.debug(_('Created symlink from %s to /system-update') % offline_file)
+    except IOError:
+        ctx.ui.error(_('Failed to prepare offline upgrade'))
+        return
+    finally:
+        ctx.ui.info(util.colorize(_('Successfully prepared offline upgrade'), 'green'))
+
 def plan_upgrade(A, force_replaced=True, replaces=None):
     # FIXME: remove force_replaced
     # try to construct a pisi graph of packages to