feat: implement configuration profiles

Author: karenc-bq

aws_advanced_python_wrapper/aurora_connection_tracker_plugin.py

@@ -64,6 +64,19 @@ def populate_opened_connection_set(self, host_info: HostInfo, conn: Connection):
 
         self._track_connection(instance_endpoint, conn)
 
+    def invalidate_current_connection(self, host_info: HostInfo, conn: Optional[Connection]):
+        host: Optional[str] = host_info.as_alias() \
+            if self._rds_utils.is_rds_instance(host_info.host) \
+            else next(alias for alias in host_info.aliases if self._rds_utils.is_rds_instance(alias))
+
+        if not host:
+            return
+
+        connection_set: Optional[WeakSet] = self._opened_connections.get(host)
+        if connection_set is not None:
+            self._log_connection_set(host, connection_set)
+            connection_set.discard(conn)
+
     def invalidate_all_connections(self, host_info: Optional[HostInfo] = None, host: Optional[FrozenSet[str]] = None):
         """
         Invalidates all opened connections pointing to the same host in a daemon thread.
@@ -77,14 +90,10 @@ def invalidate_all_connections(self, host_info: Optional[HostInfo] = None, host:
             self.invalidate_all_connections(host=host_info.as_aliases())
             return
 
-        instance_endpoint: Optional[str] = None
         if host is None:
             return
 
-        for instance in host:
-            if instance is not None and self._rds_utils.is_rds_instance(instance):
-                instance_endpoint = instance
-                break
+        instance_endpoint = next(instance for instance in host if self._rds_utils.is_rds_instance(instance))
 
         if not instance_endpoint:
             return
@@ -135,8 +144,8 @@ def log_opened_connections(self):
 
         return logger.debug("OpenedConnectionTracker.OpenedConnectionsTracked", msg)
 
-    def _log_connection_set(self, host: str, conn_set: Optional[WeakSet]):
-        if conn_set is None or len(conn_set) == 0:
+    def _log_connection_set(self, host: Optional[str], conn_set: Optional[WeakSet]):
+        if host is None or conn_set is None or len(conn_set) == 0:
             return
 
         conn = ""
@@ -148,13 +157,14 @@ def _log_connection_set(self, host: str, conn_set: Optional[WeakSet]):
 
 
 class AuroraConnectionTrackerPlugin(Plugin):
-    _SUBSCRIBED_METHODS: Set[str] = {"*"}
+    _SUBSCRIBED_METHODS: Set[str] = {"connect", "force_connect"}
     _current_writer: Optional[HostInfo] = None
     _need_update_current_writer: bool = False
+    _METHOD_CLOSE = "Connection.close"
 
     @property
     def subscribed_methods(self) -> Set[str]:
-        return self._SUBSCRIBED_METHODS
+        return AuroraConnectionTrackerPlugin._SUBSCRIBED_METHODS.union(self._plugin_service.network_bound_methods)
 
     def __init__(self,
                  plugin_service: PluginService,
@@ -201,19 +211,20 @@ def _connect(self, host_info: HostInfo, connect_func: Callable):
         return conn
 
     def execute(self, target: object, method_name: str, execute_func: Callable, *args: Any, **kwargs: Any) -> Any:
-        if self._current_writer is None or self._need_update_current_writer:
-            self._current_writer = self._get_writer(self._plugin_service.hosts)
-            self._need_update_current_writer = False
+        self._remember_writer()
 
         try:
-            return execute_func()
+            results = execute_func()
+            if method_name == AuroraConnectionTrackerPlugin._METHOD_CLOSE and self._plugin_service.current_host_info is not None:
+                self._tracker.invalidate_current_connection(self._plugin_service.current_host_info, self._plugin_service.current_connection)
+            elif self._need_update_current_writer:
+                self._check_writer_changed()
+            return results
 
         except Exception as e:
             # Check that e is a FailoverError and that the writer has changed
-            if isinstance(e, FailoverError) and self._get_writer(self._plugin_service.hosts) != self._current_writer:
-                self._tracker.invalidate_all_connections(host_info=self._current_writer)
-                self._tracker.log_opened_connections()
-                self._need_update_current_writer = True
+            if isinstance(e, FailoverError):
+                self._check_writer_changed()
             raise e
 
     def _get_writer(self, hosts: Tuple[HostInfo, ...]) -> Optional[HostInfo]:
@@ -222,6 +233,23 @@ def _get_writer(self, hosts: Tuple[HostInfo, ...]) -> Optional[HostInfo]:
                 return host
         return None
 
+    def _remember_writer(self):
+        if self._current_writer is None or self._need_update_current_writer:
+            self._current_writer = self._get_writer(self._plugin_service.hosts)
+            self._need_update_current_writer = False
+
+    def _check_writer_changed(self):
+        host_info_after_failover = self._get_writer(self._plugin_service.hosts)
+
+        if self._current_writer is None:
+            self._current_writer = host_info_after_failover
+            self._need_update_current_writer = False
+        elif self._current_writer != host_info_after_failover:
+            self._tracker.invalidate_all_connections(self._current_writer)
+            self._tracker.log_opened_connections()
+            self._current_writer = host_info_after_failover
+            self._need_update_current_writer = False
+
 
 class AuroraConnectionTrackerPluginFactory(PluginFactory):
     def get_instance(self, plugin_service: PluginService, props: Properties) -> Plugin:

aws_advanced_python_wrapper/aurora_initial_connection_strategy_plugin.py

@@ -0,0 +1,230 @@
+#  Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License").
+#  You may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#  http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+from __future__ import annotations
+
+import time
+from typing import TYPE_CHECKING, Callable, Optional, Set
+
+if TYPE_CHECKING:
+    from aws_advanced_python_wrapper.driver_dialect import DriverDialect
+    from aws_advanced_python_wrapper.pep249 import Connection
+    from aws_advanced_python_wrapper.plugin_service import PluginService
+    from aws_advanced_python_wrapper.host_list_provider import HostListProviderService
+    from aws_advanced_python_wrapper.utils.rdsutils import RdsUtils
+
+from aws_advanced_python_wrapper.errors import AwsWrapperError
+from aws_advanced_python_wrapper.host_availability import HostAvailability
+from aws_advanced_python_wrapper.hostinfo import HostInfo, HostRole
+from aws_advanced_python_wrapper.plugin import Plugin, PluginFactory
+from aws_advanced_python_wrapper.utils.messages import Messages
+from aws_advanced_python_wrapper.utils.properties import (Properties,
+                                                          WrapperProperties)
+from aws_advanced_python_wrapper.utils.rds_url_type import RdsUrlType
+
+
+class AuroraInitialConnectionStrategyPlugin(Plugin):
+    _plugin_service: PluginService
+    _host_list_provider_service: HostListProviderService
+    _rds_utils: RdsUtils
+
+    @property
+    def subscribed_methods(self) -> Set[str]:
+        return {"init_host_provider", "connect", "force_connect"}
+
+    def __init__(self, plugin_service: PluginService, properties: Properties):
+        self._plugin_service = plugin_service
+
+    def init_host_provider(self, props: Properties, host_list_provider_service: HostListProviderService, init_host_provider_func: Callable):
+        self._host_list_provider_service = host_list_provider_service
+        if host_list_provider_service.is_static_host_list_provider():
+            raise AwsWrapperError(Messages.get("AuroraInitialConnectionStrategyPlugin.RequireDynamicProvider"))
+        init_host_provider_func()
+
+    def connect(self, target_driver_func: Callable, driver_dialect: DriverDialect, host_info: HostInfo, props: Properties,
+                is_initial_connection: bool, connect_func: Callable) -> Connection:
+        return self._connect_internal(host_info, props, is_initial_connection, connect_func)
+
+    def force_connect(self, target_driver_func: Callable, driver_dialect: DriverDialect, host_info: HostInfo, props: Properties,
+                      is_initial_connection: bool, force_connect_func: Callable) -> Connection:
+        return self._connect_internal(host_info, props, is_initial_connection, force_connect_func)
+
+    def _connect_internal(self, host_info: HostInfo, props: Properties, is_initial_connection: bool, connect_func: Callable) -> Connection:
+        type: RdsUrlType = self._rds_utils.identify_rds_type(host_info.host)
+        if not type.is_rds_cluster:
+            return connect_func()
+
+        if type == RdsUrlType.RDS_WRITER_CLUSTER:
+            writer_candidate_conn = self._get_verified_writer_connection(props, is_initial_connection, connect_func)
+            if writer_candidate_conn is None:
+                return connect_func()
+            return writer_candidate_conn
+
+        if type == RdsUrlType.RDS_READER_CLUSTER:
+            reader_candidate_conn = self._get_verified_reader_connection(props, is_initial_connection, connect_func)
+            if reader_candidate_conn is None:
+                return connect_func()
+            return reader_candidate_conn
+
+        # Continue with a normal workflow.
+        return connect_func()
+
+    def _get_verified_writer_connection(self, props: Properties, is_initial_connection: bool, connect_func: Callable) -> Optional[Connection]:
+        retry_delay_ms: int = WrapperProperties.OPEN_CONNECTION_RETRY_TIMEOUT_MS.get_int(props)
+        end_time_nano = self._get_time() + retry_delay_ms * 1_000_000
+
+        writer_candidate_conn: Optional[Connection]
+        writer_candidate: Optional[HostInfo]
+
+        while self._get_time() < end_time_nano:
+            writer_candidate_conn = None
+            writer_candidate = None
+
+            try:
+                writer_candidate = self._get_writer()
+                if writer_candidate_conn is None or self._rds_utils.is_rds_cluster_dns(writer_candidate.host):
+                    writer_candidate_conn = connect_func()
+                    self._plugin_service.force_refresh_host_list(writer_candidate_conn)
+                    writer_candidate = self._plugin_service.identify_connection(writer_candidate_conn)
+
+                    if writer_candidate is not None and writer_candidate.role != HostRole.WRITER:
+                        # Shouldn't be here. But let's try again.
+                        self._close_connection(writer_candidate_conn)
+                        self._delay(retry_delay_ms)
+                        continue
+
+                    if is_initial_connection:
+                        self._host_list_provider_service.initial_connection_host_info = writer_candidate
+
+                    return writer_candidate_conn
+
+                writer_candidate_conn = self._plugin_service.connect(writer_candidate, props)
+
+                if self._plugin_service.get_host_role(writer_candidate_conn) != HostRole.WRITER:
+                    self._plugin_service.force_refresh_host_list(writer_candidate_conn)
+                    self._close_connection(writer_candidate_conn)
+                    self._delay(retry_delay_ms)
+                    continue
+
+                if is_initial_connection:
+                    self._host_list_provider_service.initial_connection_host_info = writer_candidate
+                return writer_candidate_conn
+
+            except Exception as e:
+                if writer_candidate is not None:
+                    self._plugin_service.set_availability(writer_candidate.as_aliases(), HostAvailability.UNAVAILABLE)
+                self._close_connection(writer_candidate_conn)
+                raise e
+
+        return None
+
+    def _get_verified_reader_connection(self, props: Properties, is_initial_connection: bool, connect_func: Callable) -> Optional[Connection]:
+        retry_delay_ms: int = WrapperProperties.OPEN_CONNECTION_RETRY_INTERVAL_MS.get_int(props)
+        end_time_nano = self._get_time() + WrapperProperties.OPEN_CONNECTION_RETRY_TIMEOUT_MS.get_int(props) * 1_000_000
+
+        reader_candidate_conn: Optional[Connection]
+        reader_candidate: Optional[HostInfo]
+
+        while self._get_time() < end_time_nano:
+            reader_candidate_conn = None
+            reader_candidate = None
+
+            try:
+                reader_candidate = self._get_reader(props)
+                if reader_candidate is None or self._rds_utils.is_rds_cluster_dns(reader_candidate.host):
+                    # Reader not found, topology may be outdated
+                    reader_candidate_conn = connect_func()
+                    self._plugin_service.force_refresh_host_list(reader_candidate_conn)
+                    reader_candidate = self._plugin_service.identify_connection(reader_candidate_conn)
+
+                    if reader_candidate is not None and reader_candidate.role != HostRole.READER:
+                        if self._has_no_readers():
+                            # Cluster has no readers. Simulate Aurora reader cluster endpoint logic
+                            if is_initial_connection and reader_candidate.host is not None:
+                                self._host_list_provider_service.initial_connection_host_info = reader_candidate
+                            return reader_candidate_conn
+                        self._close_connection(reader_candidate_conn)
+                        self._delay(retry_delay_ms)
+                        continue
+
+                    if reader_candidate is not None and is_initial_connection:
+                        self._host_list_provider_service.initial_connection_host_info = reader_candidate
+                    return reader_candidate_conn
+
+                reader_candidate_conn = self._plugin_service.connect(reader_candidate, props)
+                if self._plugin_service.get_host_role(reader_candidate_conn) != HostRole.READER:
+                    # If the new connection resolves to a writer instance, this means the topology is outdated.
+                    # Force refresh to update the topology.
+                    self._plugin_service.force_refresh_host_list(reader_candidate_conn)
+
+                    if self._has_no_readers():
+                        # Cluster has no readers. Simulate Aurora reader cluster endpoint logic
+                        if is_initial_connection:
+                            self._host_list_provider_service.initial_connection_host_info = reader_candidate
+                        return reader_candidate_conn
+
+                    self._close_connection(reader_candidate_conn)
+                    self._delay(retry_delay_ms)
+                    continue
+
+                # Reader connection is valid and verified.
+                if is_initial_connection:
+                    self._host_list_provider_service.initial_connection_host_info = reader_candidate
+                return reader_candidate_conn
+
+            except Exception:
+                self._close_connection(reader_candidate_conn)
+                if reader_candidate is not None:
+                    self._plugin_service.set_availability(reader_candidate.as_aliases(), HostAvailability.AVAILABLE)
+
+        return None
+
+    def _close_connection(self, connection: Optional[Connection]):
+        if connection is not None:
+            try:
+                connection.close()
+            except Exception:
+                # ignore
+                pass
+
+    def _delay(self, delay_ms: int):
+        time.sleep(delay_ms / 1000)
+
+    def _get_writer(self) -> Optional[HostInfo]:
+        return next(host for host in self._plugin_service.hosts if host.role == HostRole.WRITER)
+
+    def _get_reader(self, props: Properties) -> Optional[HostInfo]:
+        strategy: Optional[str] = WrapperProperties.READER_HOST_SELECTOR_STRATEGY.get(props)
+        if strategy is not None and self._plugin_service.accepts_strategy(HostRole.READER, strategy):
+            try:
+                return self._plugin_service.get_host_info_by_strategy(HostRole.READER, strategy)
+            except Exception:
+                # Host isn't found
+                return None
+
+        raise AwsWrapperError(Messages.get_formatted("AuroraInitialConnectionStrategyPlugin.UnsupportedStrategy", strategy))
+
+    def _has_no_readers(self) -> bool:
+        if len(self._plugin_service.hosts) == 0:
+            # Topology inconclusive.
+            return False
+        return next(host_info for host_info in self._plugin_service.hosts if host_info.role == HostRole.READER) is None
+
+    def _get_time(self):
+        return time.perf_counter_ns()
+
+
+class AuroraInitialConnectionStrategyPluginFactory(PluginFactory):
+    def get_instance(self, plugin_service: PluginService, props: Properties) -> Plugin:
+        return AuroraInitialConnectionStrategyPlugin(plugin_service, props)