Try to fix deadlock import error by lazy loading openpyxl

server/vbv_lernwelt/core/utils.py

@@ -1,6 +1,7 @@
 import json
 import re
 
+from django.utils.safestring import mark_safe
 from rest_framework.throttling import UserRateThrottle
 
 

server/vbv_lernwelt/importer/services.py

@@ -3,7 +3,6 @@ from typing import Any, Dict, List
 
 import structlog
 from django.utils import timezone
-from openpyxl.reader.excel import load_workbook
 
 from vbv_lernwelt.assignment.models import AssignmentType
 from vbv_lernwelt.core.models import User
@@ -275,6 +274,8 @@ def import_course_sessions_from_excel(
             "Basis",
             "Fahrzeug",
         ]
+    from openpyxl.reader.excel import load_workbook
+
     workbook = load_workbook(filename=filename)
     sheet = workbook["Schulungen Durchführung"]
     no_course = course is None
@@ -521,6 +522,8 @@ def get_uk_course(language: str) -> Course:
 def import_trainers_from_excel_for_training(
     filename: str, language="de", course: Course = None
 ):
+    from openpyxl.reader.excel import load_workbook
+
     workbook = load_workbook(filename=filename)
     sheet = workbook["Schulungen Trainer"]
 
@@ -609,6 +612,8 @@ def create_or_update_trainer(course: Course, data: Dict[str, Any], language="de"
 
 
 def import_students_from_excel(filename: str):
+    from openpyxl.reader.excel import load_workbook
+
     workbook = load_workbook(filename=filename)
     sheet = workbook.active
 
@@ -671,6 +676,8 @@ def _get_date_of_birth(data: Dict[str, Any]) -> str:
 
 
 def sync_students_from_t2l_excel(filename: str):
+    from openpyxl.reader.excel import load_workbook
+
     workbook = load_workbook(filename=filename)
     sheet = workbook.active