Multiple queue, multiple cluster in one site (#71)

* Support for multi-queue, multi-cluster configuration. API changes include:
  * Adding `cluster` to async_task() parameters and Task model
  * Adding argument --name to qcluster command
  * Necessary adjustments to Conf and Broker classes
  * Some admin improvements

* Add settings.Q_CLUSTER['ALT_CLUSTERS']: q_cluster config overrides for alternative clusters;
Add Conf.CLUSTER_NAME: separate usage from Conf.PREFIX;
QueueAdmin/OrmQ detail page enhanced: now displaying args/kwargs/q_options instead of encrypted payload.

* if `cluster` argument is not set (the default), async_task() and schedule() will be handled by the default cluster; Documentation update.

* Text cleanup

* Documentation update.

* Fix TIMEOUT setting in Windows for non-default cluster

---------

Co-authored-by: Stan Triepels <1939656+GDay@users.noreply.github.com>

django_q/brokers/__init__.py

@@ -7,7 +7,9 @@ from django_q.conf import Conf
 
 
 class Broker:
-    def __init__(self, list_key: str = Conf.PREFIX):
+    def __init__(self, list_key: str = None):
+        # With same BROKER_CLASS, `list_key` is just a synonym for `queue_name` except for RedisBroker
+        list_key = list_key or Conf.CLUSTER_NAME
         self.connection = self.get_connection(list_key)
         self.list_key = list_key
         self.cache = self.get_cache()
@@ -151,7 +153,7 @@ class Broker:
             return None
 
     @staticmethod
-    def get_connection(list_key: str = Conf.PREFIX):
+    def get_connection(list_key: str = None):
         """
         Gets a connection to the broker
         :param list_key: Optional queue name
@@ -160,13 +162,14 @@ class Broker:
         return 0
 
 
-def get_broker(list_key: str = Conf.PREFIX) -> Broker:
+def get_broker(list_key: str = None) -> Broker:
     """
     Gets the configured broker type
     :param list_key: optional queue name
     :type list_key: str
     :return: a broker instance
     """
+    list_key = list_key or Conf.CLUSTER_NAME
     # custom
     if Conf.BROKER_CLASS:
         module, func = Conf.BROKER_CLASS.rsplit(".", 1)

django_q/brokers/aws_sqs.py

@@ -8,7 +8,7 @@ QUEUE_DOES_NOT_EXIST = "AWS.SimpleQueueService.NonExistentQueue"
 
 
 class Sqs(Broker):
-    def __init__(self, list_key: str = Conf.PREFIX):
+    def __init__(self, list_key: str = None):
         self.sqs = None
         super(Sqs, self).__init__(list_key)
         self.queue = self.get_queue()
@@ -77,7 +77,7 @@ class Sqs(Broker):
         return "AWS SQS"
 
     @staticmethod
-    def get_connection(list_key: str = Conf.PREFIX) -> Session:
+    def get_connection(list_key: str = None) -> Session:
         config = Conf.SQS
         if "aws_region" in config:
             config["region_name"] = config["aws_region"]

django_q/brokers/ironmq.py

@@ -46,6 +46,7 @@ class IronMQBroker(Broker):
         return self.delete(task_id)
 
     @staticmethod
-    def get_connection(list_key: str = Conf.PREFIX) -> Queue:
+    def get_connection(list_key: str = None) -> Queue:
+        list_key = list_key or Conf.CLUSTER_NAME
         ironmq = IronMQ(name=None, **Conf.IRON_MQ)
         return ironmq.queue(queue_name=list_key)

django_q/brokers/mongo.py

@@ -15,7 +15,7 @@ def _timeout():
 
 
 class Mongo(Broker):
-    def __init__(self, list_key=Conf.PREFIX):
+    def __init__(self, list_key: str = None):
         super(Mongo, self).__init__(list_key)
         self.collection = self.get_collection()
 
@@ -24,7 +24,7 @@ class Mongo(Broker):
         self.collection = self.get_collection()
 
     @staticmethod
-    def get_connection(list_key: str = Conf.PREFIX) -> MongoClient:
+    def get_connection(list_key: str = None) -> MongoClient:
         return MongoClient(**Conf.MONGO)
 
     def get_collection(self):

django_q/brokers/orm.py

@@ -16,7 +16,7 @@ def _timeout():
 
 class ORM(Broker):
     @staticmethod
-    def get_connection(list_key: str = Conf.PREFIX):
+    def get_connection(list_key: str = None):
         if transaction.get_autocommit(
             using=Conf.ORM
         ):  # Only True when not in an atomic block
@@ -55,8 +55,9 @@ class ORM(Broker):
         self.delete(task_id)
 
     def enqueue(self, task):
+        # list_key might be null (e.g. in a test setup) but OrmQ.key has not-null constraint
         package = self.get_connection().create(
-            key=self.list_key, payload=task, lock=timezone.now()
+            key=self.list_key or Conf.CLUSTER_NAME, payload=task, lock=timezone.now()
         )
         return package.pk
 

django_q/brokers/redis_broker.py

@@ -11,7 +11,8 @@ except ImportError:
 
 
 class Redis(Broker):
-    def __init__(self, list_key: str = Conf.PREFIX):
+    def __init__(self, list_key: str = None):
+        list_key = list_key or Conf.CLUSTER_NAME
         super(Redis, self).__init__(list_key=f"django_q:{list_key}:q")
 
     def enqueue(self, task):
@@ -57,7 +58,7 @@ class Redis(Broker):
             return self.connection.mget(keys)
 
     @staticmethod
-    def get_connection(list_key: str = Conf.PREFIX) -> Redis:
+    def get_connection(list_key: str = None) -> Redis:
         if django_redis and Conf.DJANGO_REDIS:
             return django_redis.get_redis_connection(Conf.DJANGO_REDIS)
         if isinstance(Conf.REDIS, str):