Extract additional interfaces and abstract classes (#3754)

Author: vladvildanov

redis/multidb/circuit.py

@@ -45,16 +45,57 @@ def database(self, database):
         """Set database associated with this circuit."""
         pass
 
+class BaseCircuitBreaker(CircuitBreaker):
+    """
+    Base implementation of Circuit Breaker interface.
+    """
+    def __init__(self, cb: pybreaker.CircuitBreaker):
+        self._cb = cb
+        self._state_pb_mapper = {
+            State.CLOSED: self._cb.close,
+            State.OPEN: self._cb.open,
+            State.HALF_OPEN: self._cb.half_open,
+        }
+        self._database = None
+
+    @property
+    def grace_period(self) -> float:
+        return self._cb.reset_timeout
+
+    @grace_period.setter
+    def grace_period(self, grace_period: float):
+        self._cb.reset_timeout = grace_period
+
+    @property
+    def state(self) -> State:
+        return State(value=self._cb.state.name)
+
+    @state.setter
+    def state(self, state: State):
+        self._state_pb_mapper[state]()
+
+    @property
+    def database(self):
+        return self._database
+
+    @database.setter
+    def database(self, database):
+        self._database = database
+
+class SyncCircuitBreaker(CircuitBreaker):
+    """
+    Synchronous implementation of Circuit Breaker interface.
+    """
     @abstractmethod
-    def on_state_changed(self, cb: Callable[["CircuitBreaker", State, State], None]):
+    def on_state_changed(self, cb: Callable[["SyncCircuitBreaker", State, State], None]):
         """Callback called when the state of the circuit changes."""
         pass
 
 class PBListener(pybreaker.CircuitBreakerListener):
     """Wrapper for callback to be compatible with pybreaker implementation."""
     def __init__(
             self,
-            cb: Callable[[CircuitBreaker, State, State], None],
+            cb: Callable[[SyncCircuitBreaker, State, State], None],
             database,
     ):
         """
@@ -75,8 +116,7 @@ def state_change(self, cb, old_state, new_state):
         new_state = State(value=new_state.name)
         self._cb(cb, old_state, new_state)
 
-
-class PBCircuitBreakerAdapter(CircuitBreaker):
+class PBCircuitBreakerAdapter(SyncCircuitBreaker, BaseCircuitBreaker):
     def __init__(self, cb: pybreaker.CircuitBreaker):
         """
         Initialize a PBCircuitBreakerAdapter instance.
@@ -87,38 +127,8 @@ def __init__(self, cb: pybreaker.CircuitBreaker):
         Args:
             cb: A pybreaker CircuitBreaker instance to be adapted.
         """
-        self._cb = cb
-        self._state_pb_mapper = {
-            State.CLOSED: self._cb.close,
-            State.OPEN: self._cb.open,
-            State.HALF_OPEN: self._cb.half_open,
-        }
-        self._database = None
-
-    @property
-    def grace_period(self) -> float:
-        return self._cb.reset_timeout
-
-    @grace_period.setter
-    def grace_period(self, grace_period: float):
-        self._cb.reset_timeout = grace_period
-
-    @property
-    def state(self) -> State:
-        return State(value=self._cb.state.name)
-
-    @state.setter
-    def state(self, state: State):
-        self._state_pb_mapper[state]()
-
-    @property
-    def database(self):
-        return self._database
-
-    @database.setter
-    def database(self, database):
-        self._database = database
+        super().__init__(cb)
 
-    def on_state_changed(self, cb: Callable[["CircuitBreaker", State, State], None]):
+    def on_state_changed(self, cb: Callable[["SyncCircuitBreaker", State, State], None]):
         listener = PBListener(cb, self.database)
         self._cb.add_listener(listener)

redis/multidb/client.py

@@ -1,15 +1,12 @@
 import threading
-import socket
 from typing import List, Any, Callable, Optional
 
 from redis.background import BackgroundScheduler
-from redis.client import PubSubWorkerThread
-from redis.exceptions import ConnectionError, TimeoutError
 from redis.commands import RedisModuleCommands, CoreCommands
 from redis.multidb.command_executor import DefaultCommandExecutor
 from redis.multidb.config import MultiDbConfig, DEFAULT_GRACE_PERIOD
-from redis.multidb.circuit import State as CBState, CircuitBreaker
-from redis.multidb.database import Database, AbstractDatabase, Databases
+from redis.multidb.circuit import State as CBState, SyncCircuitBreaker
+from redis.multidb.database import Database, Databases, SyncDatabase
 from redis.multidb.exception import NoValidDatabaseException
 from redis.multidb.failure_detector import FailureDetector
 from redis.multidb.healthcheck import HealthCheck
@@ -92,7 +89,7 @@ def get_databases(self) -> Databases:
         """
         return self._databases
 
-    def set_active_database(self, database: AbstractDatabase) -> None:
+    def set_active_database(self, database: SyncDatabase) -> None:
         """
         Promote one of the existing databases to become an active.
         """
@@ -115,7 +112,7 @@ def set_active_database(self, database: AbstractDatabase) -> None:
 
         raise NoValidDatabaseException('Cannot set active database, database is unhealthy')
 
-    def add_database(self, database: AbstractDatabase):
+    def add_database(self, database: SyncDatabase):
         """
         Adds a new database to the database list.
         """
@@ -129,7 +126,7 @@ def add_database(self, database: AbstractDatabase):
         self._databases.add(database, database.weight)
         self._change_active_database(database, highest_weighted_db)
 
-    def _change_active_database(self, new_database: AbstractDatabase, highest_weight_database: AbstractDatabase):
+    def _change_active_database(self, new_database: SyncDatabase, highest_weight_database: SyncDatabase):
         if new_database.weight > highest_weight_database.weight and new_database.circuit.state == CBState.CLOSED:
             self.command_executor.active_database = new_database
 
@@ -143,7 +140,7 @@ def remove_database(self, database: Database):
         if highest_weight <= weight and highest_weighted_db.circuit.state == CBState.CLOSED:
             self.command_executor.active_database = highest_weighted_db
 
-    def update_database_weight(self, database: AbstractDatabase, weight: float):
+    def update_database_weight(self, database: SyncDatabase, weight: float):
         """
         Updates a database from the database list.
         """
@@ -210,7 +207,7 @@ def pubsub(self, **kwargs):
 
         return PubSub(self, **kwargs)
 
-    def _check_db_health(self, database: AbstractDatabase, on_error: Callable[[Exception], None] = None) -> None:
+    def _check_db_health(self, database: SyncDatabase, on_error: Callable[[Exception], None] = None) -> None:
         """
         Runs health checks on the given database until first failure.
         """
@@ -247,15 +244,15 @@ def _check_databases_health(self, on_error: Callable[[Exception], None] = None):
         for database, _ in self._databases:
             self._check_db_health(database, on_error)
 
-    def _on_circuit_state_change_callback(self, circuit: CircuitBreaker, old_state: CBState, new_state: CBState):
+    def _on_circuit_state_change_callback(self, circuit: SyncCircuitBreaker, old_state: CBState, new_state: CBState):
         if new_state == CBState.HALF_OPEN:
             self._check_db_health(circuit.database)
             return
 
         if old_state == CBState.CLOSED and new_state == CBState.OPEN:
             self._bg_scheduler.run_once(DEFAULT_GRACE_PERIOD, _half_open_circuit, circuit)
 
-def _half_open_circuit(circuit: CircuitBreaker):
+def _half_open_circuit(circuit: SyncCircuitBreaker):
     circuit.state = CBState.HALF_OPEN
 
 
@@ -450,8 +447,8 @@ def run_in_thread(
         exception_handler: Optional[Callable] = None,
         sharded_pubsub: bool = False,
     ) -> "PubSubWorkerThread":
-        return self._client.command_executor.execute_pubsub_run_in_thread(
-            sleep_time=sleep_time,
+        return self._client.command_executor.execute_pubsub_run(
+            sleep_time,
             daemon=daemon,
             exception_handler=exception_handler,
             pubsub=self,