disable cron command if settings.DISABLE_CRON_JOBS is set (#26863)

tests/test_publisher.py

@@ -10,8 +10,10 @@ import zipfile
 import mock
 import pytest
 
+from django.conf import settings
 from django.core.management import call_command
 from django.core.management.base import CommandError
+from django.test import override_settings
 from quixote import cleanup
 from wcs.qommon.http_request import HTTPRequest
 
@@ -205,3 +207,9 @@ def test_cron_command():
     with mock.patch('wcs.qommon.management.commands.cron.cron_worker') as cron_worker:
         call_command('cron')
         assert cron_worker.call_count == 1
+
+    # disable cron system
+    with override_settings(DISABLE_CRON_JOBS=True):
+        with mock.patch('wcs.qommon.management.commands.cron.cron_worker') as cron_worker:
+            call_command('cron')
+            assert cron_worker.call_count == 0

wcs/qommon/management/commands/cron.py

@@ -18,6 +18,7 @@ import tempfile
 import time
 import os
 
+from django.conf import settings
 from django.core.management.base import BaseCommand, CommandError
 from qommon.publisher import get_publisher_class
 
@@ -31,8 +32,14 @@ class Command(BaseCommand):
 
     def add_arguments(self, parser):
         parser.set_defaults(verbosity=0)
+        parser.add_argument('--force-job', dest='force_job', action='store_true',
+            help='Run even if DISABLE_CRON_JOBS is set in settings')
 
-    def handle(self, verbosity, **kwargs):
+    def handle(self, verbosity, **options):
+        if getattr(settings, 'DISABLE_CRON_JOBS', False) and not options['force_job']:
+            if verbosity > 1:
+                print('Command is ignored because DISABLE_CRON_JOBS is set in settings')
+            return
         lockfile = os.path.join(tempfile.gettempdir(), 'wcs-cron-in-progress.lock')
         try:
             with locket.lock_file(lockfile, timeout=0):

wcs/settings.py

@@ -159,6 +159,11 @@ REQUESTS_PROXIES = None
 # we use 28s by default: timeout just before web server, which is usually 30s
 REQUESTS_TIMEOUT = 28
 
+# For high availability installations with multiple instances of w.c.s.
+# components, one should disable cron jobs execution on secondary servers;
+# set the following variable True disables "cron" management command
+DISABLE_CRON_JOBS = False
+
 local_settings_file = os.environ.get('WCS_SETTINGS_FILE',
         os.path.join(os.path.dirname(__file__), 'local_settings.py'))
 if os.path.exists(local_settings_file):