Add to worker redis record scheduler info (#1787)

* add scheduler_pid property to queue

* Update return type

* Reformat code

rq/queue.py

@@ -3,11 +3,11 @@ import sys
 import traceback
 import uuid
 import warnings
-
 from collections import namedtuple
 from datetime import datetime, timezone, timedelta
 from functools import total_ordering
 from typing import TYPE_CHECKING, Dict, List, Any, Callable, Optional, Tuple, Type, Union
+
 from redis import WatchError
 
 if TYPE_CHECKING:
@@ -24,7 +24,6 @@ from .types import FunctionReferenceType, JobDependencyType
 from .serializers import resolve_serializer
 from .utils import backend_class, get_version, import_attribute, make_colorizer, parse_timeout, utcnow, compact
 
-
 green = make_colorizer('darkgreen')
 yellow = make_colorizer('darkyellow')
 blue = make_colorizer('darkblue')
@@ -119,7 +118,7 @@ class Queue:
         prefix = cls.redis_queue_namespace_prefix
         if not queue_key.startswith(prefix):
             raise ValueError('Not a valid RQ queue key: {0}'.format(queue_key))
-        name = queue_key[len(prefix) :]
+        name = queue_key[len(prefix):]
         return cls(name, connection=connection, job_class=job_class, serializer=serializer)
 
     def __init__(
@@ -196,6 +195,12 @@ class Queue:
         """Redis key used to indicate this queue has been cleaned."""
         return 'rq:clean_registries:%s' % self.name
 
+    @property
+    def scheduler_pid(self) -> int:
+        from rq.scheduler import RQScheduler
+        pid = self.connection.get(RQScheduler.get_locking_key(self.name))
+        return int(pid.decode()) if pid is not None else None
+
     def acquire_cleaning_lock(self) -> bool:
         """Returns a boolean indicating whether a lock to clean this queue
         is acquired. A lock expires in 899 seconds (15 minutes - 1 second)

tests/test_scheduler.py

@@ -1,9 +1,10 @@
 import os
 from datetime import datetime, timedelta, timezone
 from multiprocessing import Process
-
 from unittest import mock
+
 from rq import Queue
+from rq.defaults import DEFAULT_MAINTENANCE_TASK_INTERVAL
 from rq.exceptions import NoSuchJobError
 from rq.job import Job, Retry
 from rq.registry import FinishedJobRegistry, ScheduledJobRegistry
@@ -11,10 +12,7 @@ from rq.scheduler import RQScheduler
 from rq.serializers import JSONSerializer
 from rq.utils import current_timestamp
 from rq.worker import Worker
-from rq.defaults import DEFAULT_MAINTENANCE_TASK_INTERVAL
-
 from tests import RQTestCase, find_empty_redis_database, ssl_test
-
 from .fixtures import kill_worker, say_hello
 
 
@@ -140,7 +138,7 @@ class TestScheduler(RQTestCase):
         # scheduler.should_reacquire_locks always returns False if
         # scheduler.acquired_locks and scheduler._queue_names are the same
         self.assertFalse(scheduler.should_reacquire_locks)
-        scheduler.lock_acquisition_time = datetime.now() - timedelta(seconds=DEFAULT_MAINTENANCE_TASK_INTERVAL+6)
+        scheduler.lock_acquisition_time = datetime.now() - timedelta(seconds=DEFAULT_MAINTENANCE_TASK_INTERVAL + 6)
         self.assertFalse(scheduler.should_reacquire_locks)
 
         scheduler._queue_names = set(['default', 'foo'])
@@ -196,6 +194,12 @@ class TestScheduler(RQTestCase):
             self.assertEqual(mocked.call_count, 1)
             self.assertEqual(stopped_process.is_alive.call_count, 1)
 
+    def test_queue_scheduler_pid(self):
+        queue = Queue(connection=self.testconn)
+        scheduler = RQScheduler([queue, ], connection=self.testconn)
+        scheduler.acquire_locks()
+        assert queue.scheduler_pid == os.getpid()
+
     def test_heartbeat(self):
         """Test that heartbeat updates locking keys TTL"""
         name_1 = 'lock-test-1'