fix: ensure that prepared report is set even on timeout (#25565)

* fix: ensure that prepared report is set even on timeout

Under following condition prepared report is never enabled:
- Process takes too much time and is killed
- HTTP timeout

Fix:
- We spawn a thread and ask it to wait till prepared report threshold
  time is elapsed and set prepared report on it.
- Condvar is used to immdiately wake up and end the thread if report
  finsihed early.

* refactor: use threading.Timer

No need to implement it ourselves

frappe/core/doctype/report/report.py

@@ -2,6 +2,7 @@
 # License: MIT. See LICENSE
 import datetime
 import json
+import threading
 
 import frappe
 import frappe.desk.query_report
@@ -15,6 +16,8 @@ from frappe.modules.export_file import export_to_files
 from frappe.utils import cint, cstr
 from frappe.utils.safe_exec import check_safe_sql_query, safe_exec
 
+PREPARED_REPORT_THRESHOLD = 20  # seconds
+
 
 class Report(Document):
 	# begin: auto-generated types
@@ -153,21 +156,24 @@ class Report(Document):
 
 	def execute_script_report(self, filters):
 		# save the timestamp to automatically set to prepared
-		threshold = 15
-
 		start_time = datetime.datetime.now()
 
+		if not self.prepared_report:
+			set_prepared_report = threading.Timer(
+				interval=PREPARED_REPORT_THRESHOLD,
+				function=enable_prepared_report,
+				kwargs={"report": self.name, "site": frappe.local.site},
+			)
+			set_prepared_report.start()
+
 		# The JOB
 		if self.is_standard == "Yes":
 			res = self.execute_module(filters)
 		else:
 			res = self.execute_script(filters)
 
-		# automatically set as prepared
+		set_prepared_report.cancel()
 		execution_time = (datetime.datetime.now() - start_time).total_seconds()
-		if execution_time > threshold and not self.prepared_report:
-			frappe.enqueue(enable_prepared_report, report=self.name)
-
 		frappe.cache.hset("report_execution_time", self.name, execution_time)
 
 		return res
@@ -414,5 +420,9 @@ def get_group_by_column_label(args, meta):
 	return label
 
 
-def enable_prepared_report(report: str):
-	frappe.db.set_value("Report", report, "prepared_report", 1)
+def enable_prepared_report(*, site: str, report: str):
+	frappe.init(site)
+	frappe.connect()
+	frappe.db.set_value("Report", report, "prepared_report", 1, update_modified=True)
+	frappe.db.commit()
+	frappe.destroy()