Made redis storage a singleton in order to reduce number of connections

src/django_clickhouse/storages.py

@@ -11,12 +11,13 @@ import logging
 from typing import Any, Optional, List, Tuple
 
 import os
+from six import with_metaclass
 from statsd.defaults.django import statsd
 
 from .configuration import config
 from .exceptions import ConfigurationError, RedisLockTimeoutError
 from .redis import redis_zadd
-from .utils import check_pid, get_subclasses
+from .utils import check_pid, get_subclasses, SingletonMeta
 
 logger = logging.getLogger('django-clickhouse')
 
@@ -143,7 +144,7 @@ class Storage:
         raise NotImplemented()
 
 
-class RedisStorage(Storage):
+class RedisStorage(with_metaclass(SingletonMeta, Storage)):
     """
     Fast in-memory storage made on bases of redis and redis-py library.
     Requires:

src/django_clickhouse/utils.py

@@ -259,3 +259,15 @@ def exec_multi_arg_func(func: Callable, split_args: Iterable[Any], *args, thread
             q.put(([s] + list(args), kwargs))
 
         return exec_in_parallel(func, q, threads_count=threads_count)
+
+
+class SingletonMeta(type):
+    """
+    Realises singleton pattern
+    """
+    _instances = {}
+
+    def __call__(cls, *args, **kwargs):
+        if cls not in cls._instances:
+            cls._instances[cls] = super(SingletonMeta, cls).__call__(*args, **kwargs)
+        return cls._instances[cls]

tests/test_utils.py

@@ -3,9 +3,11 @@ from queue import Queue
 
 import pytz
 from django.test import TestCase
+from six import with_metaclass
 
 from django_clickhouse.models import ClickHouseSyncModel
-from django_clickhouse.utils import get_tz_offset, format_datetime, lazy_class_import, int_ranges, exec_in_parallel
+from django_clickhouse.utils import get_tz_offset, format_datetime, lazy_class_import, int_ranges, exec_in_parallel, \
+    SingletonMeta
 
 
 class GetTZOffsetTest(TestCase):
@@ -99,3 +101,17 @@ class TestExecInParallel(TestCase):
 
         with self.assertRaises(TypeError):
             exec_in_parallel(_test_func, q)
+
+
+class TestSingletonMeta(TestCase):
+    def test_singleton(self):
+        class Single(with_metaclass(SingletonMeta)):
+            def __init__(self):
+                self.test = 1
+
+        a = Single()
+        a.test += 1
+        b = Single()
+        self.assertEqual(a, b)
+        self.assertEqual(2, b.test)
+