From 9d3be5160fc21eaefcb655aa5ca38bc51e18b424 Mon Sep 17 00:00:00 2001
From: Sagar Vora <sagar@resilient.tech>
Date: Thu, 22 Apr 2021 12:24:12 +0530
Subject: [PATCH] perf: low priority for backup processes

---
 frappe/utils/__init__.py | 13 +++++++++++--
 frappe/utils/backups.py  | 14 ++++++--------
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/frappe/utils/__init__.py b/frappe/utils/__init__.py
index efa69d4453..251a095343 100644
--- a/frappe/utils/__init__.py
+++ b/frappe/utils/__init__.py
@@ -307,14 +307,23 @@ def unesc(s, esc_chars):
 		s = s.replace(esc_str, c)
 	return s
 
-def execute_in_shell(cmd, verbose=0):
+def execute_in_shell(cmd, verbose=0, low_priority=False):
 	# using Popen instead of os.system - as recommended by python docs
 	import tempfile
 	from subprocess import Popen
 
 	with tempfile.TemporaryFile() as stdout:
 		with tempfile.TemporaryFile() as stderr:
-			p = Popen(cmd, shell=True, stdout=stdout, stderr=stderr)
+			kwargs = {
+				"shell": True,
+				"stdout": stdout,
+				"stderr": stderr
+			}
+
+			if low_priority:
+				kwargs["preexec_fn"] = lambda: os.nice(10)
+
+			p = Popen(cmd, **kwargs)
 			p.wait()
 
 			stdout.seek(0)
diff --git a/frappe/utils/backups.py b/frappe/utils/backups.py
index 9a6747a0cf..90a6b94ff0 100644
--- a/frappe/utils/backups.py
+++ b/frappe/utils/backups.py
@@ -315,8 +315,6 @@ class BackupGenerator:
 			print(template.format(_type.title(), info["path"], info["size"]))
 
 	def backup_files(self):
-		import subprocess
-
 		for folder in ("public", "private"):
 			files_path = frappe.get_site_path(folder, "files")
 			backup_path = (
@@ -327,12 +325,12 @@ class BackupGenerator:
 				cmd_string = "tar cf - {1} | gzip > {0}"
 			else:
 				cmd_string = "tar -cf {0} {1}"
-			output = subprocess.check_output(
-				cmd_string.format(backup_path, files_path), shell=True
-			)
 
-			if self.verbose and output:
-				print(output.decode("utf8"))
+			frappe.utils.execute_in_shell(
+				cmd_string.format(backup_path, files_path),
+				verbose=self.verbose,
+				low_priority=True
+			)
 
 	def copy_site_config(self):
 		site_config_backup_path = self.backup_path_conf
@@ -436,7 +434,7 @@ class BackupGenerator:
 		if self.verbose:
 			print(command + "\n")
 
-		err, out = frappe.utils.execute_in_shell(command)
+		err, out = frappe.utils.execute_in_shell(command, low_priority=True)
 
 	def send_email(self):
 		"""