Added locking mechanism to logparser command

see #2754

modoboa/core/commands/templates/settings.py.tpl

@@ -230,6 +230,8 @@ MODOBOA_API_URL = 'https://api.modoboa.org/1/'
 
 DISABLE_DASHBOARD_EXTERNAL_QUERIES = False
 
+PID_FILE_STORAGE_PATH = '/var/run'
+
 # REDIS
 
 REDIS_HOST = 'localhost'

modoboa/maillog/management/commands/logparser.py

@@ -27,6 +27,7 @@ import time
 
 import rrdtool
 
+from django.conf import settings
 from django.core.management.base import BaseCommand
 from django.db.models import Q
 from django.utils import timezone
@@ -619,7 +620,27 @@ class Command(BaseCommand):
             "--debug", default=False, action="store_true",
             help="Set debug mode")
 
+    def can_start(self):
+        """Check if another process is already running or not."""
+        pidfile = f"{settings.PID_FILE_STORAGE_PATH}/modoboa_logparser.pid"
+        if os.path.exists(pidfile):
+            with open(pidfile) as fp:
+                pid = fp.read()
+            pid = int(pid.strip())
+            try:
+                os.kill(pid, 0)
+            except OSError:
+                pass
+            else:
+                return False
+        with open(pidfile, "w") as fp:
+            fp.write(f"{os.getpid()}\n")
+        return True
+
     def handle(self, *args, **options):
+        if not self.can_start():
+            print("Another process is already running, cannot start")
+            sys.exit(2)
         if options["logfile"] is None:
             options["logfile"] = param_tools.get_global_parameter(
                 "logfile", app="maillog")

modoboa/maillog/tests/test_views.py

@@ -5,6 +5,7 @@ import os
 import shutil
 import tempfile
 
+from django.conf import settings
 from django.core.management import call_command
 from django.urls import reverse
 from django.test import override_settings
@@ -24,6 +25,9 @@ class RunCommandsMixin(object):
 
     def tearDown(self):
         shutil.rmtree(self.workdir)
+        pid_file = f"{settings.PID_FILE_STORAGE_PATH}/modoboa_logparser.pid"
+        if os.path.exists(pid_file):
+            os.remove(pid_file)
 
     def run_logparser(self):
         """Run logparser command."""
@@ -166,3 +170,10 @@ class ManagementCommandsTestCase(RunCommandsMixin, ModoTestCase):
         self.assertTrue(os.path.exists(path))
         self.run_update_statistics(rebuild=True)
         self.assertTrue(os.path.exists(path))
+
+    def test_locking(self):
+        with open(f"{settings.PID_FILE_STORAGE_PATH}/modoboa_logparser.pid", "w") as fp:
+            fp.write(f"{os.getpid()}\n")
+        with self.assertRaises(SystemExit) as inst:
+            self.run_logparser()
+        self.assertEqual(inst.exception.code, 2)

test_project/test_project/settings.py

@@ -212,6 +212,8 @@ SPECTACULAR_SETTINGS = {
 
 MODOBOA_API_URL = 'https://api.modoboa.org/1/'
 
+PID_FILE_STORAGE_PATH = '/tmp'
+
 # REDIS
 
 REDIS_HOST = 'localhost'