Save and read lighting backups (Qt)

electrum/gui/qt/__init__.py

@@ -233,6 +233,7 @@ class ElectrumGui(Logger):
         run_hook('on_new_window', w)
         w.warn_if_testnet()
         w.warn_if_watching_only()
+        w.warn_if_lightning_backup()
         return w
 
     def count_wizards_in_progress(func):

electrum/gui/qt/channels_list.py

@@ -8,7 +8,7 @@ from PyQt5.QtWidgets import QMenu, QHBoxLayout, QLabel, QVBoxLayout, QGridLayout
 
 from electrum.util import bh2u, NotEnoughFunds, NoDynamicFeeEstimates
 from electrum.i18n import _
-from electrum.lnchannel import Channel
+from electrum.lnchannel import Channel, peer_states
 from electrum.wallet import Abstract_Wallet
 from electrum.lnutil import LOCAL, REMOTE, format_short_channel_id, LN_MAX_FUNDING_SAT
 
@@ -84,10 +84,14 @@ class ChannelsList(MyTreeView):
         WaitingDialog(self, 'please wait..', task, self.on_success, self.on_failure)
 
     def force_close(self, channel_id):
+        if self.lnworker.wallet.is_lightning_backup():
+            msg = _('<b>WARNING<b>: force-closing from an old state might result in fund loss.\nAre you sure?')
+        else:
+            msg = _('Force-close channel?\nReclaimed funds will not be immediately available.')
+        if self.parent.question(msg):
             def task():
                 coro = self.lnworker.force_close_channel(channel_id)
                 return self.network.run_from_another_thread(coro)
-        if self.parent.question('Force-close channel?\nReclaimed funds will not be immediately available.'):
             WaitingDialog(self, 'please wait..', task, self.on_success, self.on_failure)
 
     def remove_channel(self, channel_id):
@@ -105,6 +109,7 @@ class ChannelsList(MyTreeView):
         menu.addAction(_("Details..."), lambda: self.details(channel_id))
         self.add_copy_menu(menu, idx)
         if not chan.is_closed():
+            if chan.peer_state == peer_states.GOOD:
                 menu.addAction(_("Close channel"), lambda: self.close_channel(channel_id))
             menu.addAction(_("Force-close channel"), lambda: self.force_close(channel_id))
         else:

electrum/gui/qt/main_window.py

@@ -513,6 +513,18 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
             ])
             self.show_warning(msg, title=_('Watch-only wallet'))
 
+    def warn_if_lightning_backup(self):
+        if self.wallet.is_lightning_backup():
+            msg = '\n\n'.join([
+                _("This file is a backup of a lightning wallet."),
+                _("You will not be able to perform lightning payments using this file, and the lightning balance displayed in this wallet might be outdated.") + ' ' + \
+                _("If you have lost the original wallet file, you can use this file to trigger a forced closure of your channels."),
+                _("Do you want to have your channels force-closed?")
+            ])
+            if self.question(msg, title=_('Lightning Backup')):
+                self.network.maybe_init_lightning()
+                self.wallet.lnworker.start_network(self.network)
+
     def warn_if_testnet(self):
         if not constants.net.TESTNET:
             return
@@ -549,7 +561,6 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
             return
         self.gui_object.new_window(filename)
 
-
     def backup_wallet(self):
         path = self.wallet.storage.path
         wallet_folder = os.path.dirname(path)
@@ -557,12 +568,14 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
         if not filename:
             return
         new_path = os.path.join(wallet_folder, filename)
-        if new_path != path:
+        if new_path == path:
+            return
         try:
-                shutil.copy2(path, new_path)
-                self.show_message(_("A copy of your wallet file was created in")+" '%s'" % str(new_path), title=_("Wallet backup created"))
+            self.wallet.save_backup(new_path)
         except BaseException as reason:
             self.show_critical(_("Electrum was unable to copy your wallet file to the specified location.") + "\n" + str(reason), title=_("Unable to create backup"))
+            return
+        self.show_message(_("A copy of your wallet file was created in")+" '%s'" % str(new_path), title=_("Wallet backup created"))
 
     def update_recently_visited(self, filename):
         recent = self.config.get('recently_open', [])

electrum/wallet.py

@@ -263,6 +263,13 @@ class Abstract_Wallet(AddressSynchronizer, ABC):
         if self.storage:
             self.db.write(self.storage)
 
+    def save_backup(self, path):
+        # fixme: we need to change password...
+        new_storage = WalletStorage(path)
+        self.db.put('is_backup', True)
+        self.db.write(new_storage)
+        self.db.put('is_backup', None)
+
     def has_lightning(self):
         return bool(self.lnworker)
 
@@ -285,6 +292,9 @@ class Abstract_Wallet(AddressSynchronizer, ABC):
         self.db.put('lightning_privkey2', None)
         self.save_db()
 
+    def is_lightning_backup(self):
+        return self.has_lightning() and self.db.get('is_backup')
+
     def stop_threads(self):
         super().stop_threads()
         if any([ks.is_requesting_to_be_rewritten_to_wallet_file for ks in self.get_keystores()]):
@@ -301,7 +311,7 @@ class Abstract_Wallet(AddressSynchronizer, ABC):
 
     def start_network(self, network):
         AddressSynchronizer.start_network(self, network)
-        if self.lnworker and network:
+        if self.lnworker and network and not self.is_lightning_backup():
             network.maybe_init_lightning()
             self.lnworker.start_network(network)