From bf45cd7c4b1ff575ef679fdcc44ee77170fd6cb1 Mon Sep 17 00:00:00 2001
From: Maniack Crudelis <maniackcrudelis@users.noreply.github.com>
Date: Fri, 28 Jul 2017 18:53:43 +0200
Subject: [PATCH] =?UTF-8?q?New=20helpers=20ynh=5Fbackup=5Fafter=5Ffailed?=
 =?UTF-8?q?=5Fupgrade=20and=20ynh=5Fbackup=5Fbefore=5Fupg=E2=80=A6=20(#289?=
 =?UTF-8?q?)?=
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* New helpers ynh_backup_after_failed_upgrade and ynh_backup_before_upgrade
Create a backup at the beginning of upgrade script.
Then, if the upgrade script failed, remove the app and restore it.
The backup is kept, to provide a way to restore if the upgrade is finally a bad thing.
* Implement @JimboJoe's comments
* Indentation
* --ignore-hooks -> --ignore-system
---
 data/helpers.d/utils | 60 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/data/helpers.d/utils b/data/helpers.d/utils
index 8ff9e5791..bfa6ebbf2 100644
--- a/data/helpers.d/utils
+++ b/data/helpers.d/utils
@@ -25,6 +25,66 @@ ynh_get_plain_key() {
     done
 }
 
+# Restore a previous backup if the upgrade process failed
+#
+# usage:
+# ynh_backup_before_upgrade
+# ynh_clean_setup () {
+# 	ynh_backup_after_failed_upgrade
+# }
+# ynh_abort_if_errors
+#
+ynh_backup_after_failed_upgrade () {
+	echo "Upgrade failed." >&2
+	app_bck=${app//_/-}	# Replace all '_' by '-'
+	
+        # Check if an existing backup can be found before removing and restoring the application.
+	if sudo yunohost backup list | grep -q $app_bck-pre-upgrade$backup_number
+    	then
+		# Remove the application then restore it
+		sudo yunohost app remove $app
+		# Restore the backup
+		sudo yunohost backup restore --ignore-system $app_bck-pre-upgrade$backup_number --apps $app --force
+		ynh_die "The app was restored to the way it was before the failed upgrade."
+	fi
+}
+
+# Make a backup in case of failed upgrade
+#
+# usage:
+# ynh_backup_before_upgrade
+# ynh_clean_setup () {
+# 	ynh_backup_after_failed_upgrade
+# }
+# ynh_abort_if_errors
+#
+ynh_backup_before_upgrade () {
+	backup_number=1
+	old_backup_number=2
+	app_bck=${app//_/-}	# Replace all '_' by '-'
+	
+    	# Check if a backup already exists with the prefix 1
+	if sudo yunohost backup list | grep -q $app_bck-pre-upgrade1
+    	then
+        	# Prefix becomes 2 to preserve the previous backup
+		backup_number=2
+		old_backup_number=1
+	fi
+
+	# Create backup
+	sudo yunohost backup create --ignore-system --apps $app --name $app_bck-pre-upgrade$backup_number
+	if [ "$?" -eq 0 ]
+    	then
+		# If the backup succeeded, remove the previous backup
+		if sudo yunohost backup list | grep -q $app_bck-pre-upgrade$old_backup_number
+		then
+			# Remove the previous backup only if it exists
+			sudo yunohost backup delete $app_bck-pre-upgrade$old_backup_number > /dev/null
+		fi
+	else
+		ynh_die "Backup failed, the upgrade process was aborted."
+	fi
+
 # Download, check integrity, uncompress and patch the source from app.src
 #
 # The file conf/app.src need to contains: