[389-devel] back ported dnf pretransaction for fedora 25

Hello Everyone,

I back ported the function pretransaction into dnf plugin from fedora 25, because
I’ don’t wanna break the current system.

Source can be found at:

https://copr.fedorainfracloud.org/coprs/andybe/BtrfsF25/

dnf-1.1.10-7.fc25.src.rpm
dnf-plugins-extras-0.0.12-5.fc25.src.rpm

0001-dnf-plugin-add-pretransaction.patch 

diff --git a/dnf/base.py b/dnf/base.py
index eade03d..46e1e40 100644
--- a/dnf/base.py
+++ b/dnf/base.py
@@ -603,6 +603,8 @@ class Base(object):
                 for display_ in cb.displays:
                     display_.output = False
 
+            self._plugins.run_pre_transaction()
+
             logger.info(_('Running transaction'))
             self._run_transaction(cb=cb)
         timer()
diff --git a/dnf/plugin.py b/dnf/plugin.py
index c611cc3..0978db8 100644
--- a/dnf/plugin.py
+++ b/dnf/plugin.py
@@ -67,6 +67,9 @@ class Plugin(object):
     def sack(self):
         # :api
         pass
+    def pre_transaction(self):
+        # :api
+        pass
 
     def transaction(self):
         # :api
@@ -106,6 +109,7 @@ class Plugins(object):
 
     run_sack = _caller('sack')
     run_resolved = _caller('resolved')
+    run_pre_transaction = _caller('pre_transaction')
     run_transaction = _caller('transaction')
 
     def unload(self):
diff --git a/doc/api_plugins.rst b/doc/api_plugins.rst
index e2e15ba..8845a3c 100644
--- a/doc/api_plugins.rst
+++ b/doc/api_plugins.rst
@@ -55,6 +55,10 @@ When DNF CLI runs it loads the plugins found in the paths during the
CLI's initi
 
     Plugin can override this. This hook is called immediately after :attr:`.Base.sack` is
initialized with data from all the enabled repos.
 
+  .. method:: pre_transaction
+
+    Plugin can override this. This hook is called just before transaction execution. This
means after a successful transaction test. RPMDB is locked during that time.
+
   .. method:: transaction
 
     Plugin can override this. This hook is called immediately after a successful
transaction.
diff --git a/doc/api_vs_yum.rst b/doc/api_vs_yum.rst
index 65b6a35..7c421e6 100644
--- a/doc/api_vs_yum.rst
+++ b/doc/api_vs_yum.rst
@@ -37,7 +37,7 @@ Hook Number  Yum hook           DNF hook
 ``6``        ``prereposetup``          
 ``7``        ``postreposetup``  ``sack``
 ``8``        ``exclude``        ``resolved``
-``9``        ``preresolve``              
+``9``        ``preresolve``     ``pre_transaction       
 ``10``       ``postresolve``    ``resolved but no re-resolve``
 ``11``       ``pretrans``              
 ``12``       ``postrans``       ``transaction``
 




dnf-plugins-extras-0.0.12

snapper_prepost.patch

diff --git a/plugins/snapper.py b/plugins/snapper.py
index d0443b0..877be38 100644
--- a/plugins/snapper.py
+++ b/plugins/snapper.py
@@ -1,6 +1,7 @@
 # creates snapshots via 'snapper'.
 #
 # Copyright (C) 2014 Igor Gnatenko
+# Copyright (C) 2017 Andreas Benzler
 #
 # This copyrighted material is made available to anyone wishing to use,
 # modify, copy, or redistribute it subject to the terms and conditions of
@@ -31,17 +32,11 @@ class Snapper(dnf.Plugin):
     def __init__(self, base, cli):
         self.base = base
         self.description = " ".join(sys.argv)
+        self.snapper = None
+        self.pre_id = None
 
-    def transaction(self):
-        if not len(self.base.transaction):
-            return
-
-        if dnfpluginsextras.is_erasing(self.base.transaction,
-                                       "snapper"):
-            return
         try:
-            bus = SystemBus()
-            snapper = Interface(bus.get_object('org.opensuse.Snapper',
+            self.snapper =
Interface(SystemBus().get_object('org.opensuse.Snapper',
                                                '/org/opensuse/Snapper'),
                                 dbus_interface='org.opensuse.Snapper')
         except DBusException as e:
@@ -49,15 +44,37 @@ class Snapper(dnf.Plugin):
                 "snapper: " + _("connect to snapperd failed: %s"), e
             )
             return
+
+    def pre_transaction(self):
+        if not len(self.base.transaction):
+            return
+
         try:
+            logger.debug("snapper:" + _("creating snapshot") + "
(pre)"
+            )
+            self.pre_id = self.snapper.CreatePreSnapshot('root',
self.description, 'number', {})
             logger.debug(
-                "snapper: " + _("creating snapshot")
+                "snapper: " + _("created snapshot %d"), self.pre_id
+            )
+
+        except DBusException as e:
+            logger.critical(
+                "snapper: " + _("creating snapshot failed: %s"), e
+            )
+
+    def transaction(self):
+        if not len(self.base.transaction):
+            return
+
+
+        try:
+            logger.debug("snapper:" + _("creating snapshot") + "
(post)"
             )
-            snap = snapper.CreateSingleSnapshot("root", self.description,
-                                                "number", {})
+            post_id = self.snapper.CreatePostSnapshot('root',  str(self.pre_id)
,'', 'number',{})
             logger.debug(
-                "snapper: " + _("created snapshot %d"), snap
+                "snapper: " + _("created snapshot %d"), post_id
             )
+
         except DBusException as e:
             logger.critical(
                 "snapper: " + _("creating snapshot failed: %s"), e