Load botocore i/o methods in executor

aiobotocore/client.py

@@ -1,3 +1,5 @@
+import asyncio
+
 from botocore.auth import resolve_auth_type
 from botocore.awsrequest import prepare_request_dict
 from botocore.client import (
@@ -41,26 +43,23 @@ async def create_client(
         api_version=None,
         client_config=None,
         auth_token=None,
+        load_executor=False,
     ):
         responses = await self._event_emitter.emit(
             'choose-service-name', service_name=service_name
         )
         service_name = first_non_none_response(responses, default=service_name)
-        service_model = self._load_service_model(service_name, api_version)
-        try:
-            endpoints_ruleset_data = self._load_service_endpoints_ruleset(
-                service_name, api_version
-            )
-            partition_data = self._loader.load_data('partitions')
-        except UnknownServiceError:
-            endpoints_ruleset_data = None
-            partition_data = None
-            logger.info(
-                'No endpoints ruleset found for service %s, falling back to '
-                'legacy endpoint routing.',
-                service_name,
+        logger.debug(
+            "AioClientCreator - Method load_service_model[botocore] could generate I/O. Running in executor: %s",
+            load_executor,
+        )
+        if load_executor:
+            model_data = await asyncio.get_running_loop().run_in_executor(
+                None, self._load_models, service_name, api_version
             )
-
+        else:
+            model_data = self._load_models(service_name, api_version)
+        service_model, endpoints_ruleset_data, partition_data = model_data
         cls = await self._create_client_class(service_name, service_model)
         region_name, client_config = self._normalize_fips_region(
             region_name, client_config
@@ -109,6 +108,23 @@ async def create_client(
         )
         return service_client
 
+    def _load_models(self, service_name, api_version):
+        service_model = self._load_service_model(service_name, api_version)
+        try:
+            endpoints_ruleset_data = self._load_service_endpoints_ruleset(
+                service_name, api_version
+            )
+            partition_data = self._loader.load_data('partitions')
+        except UnknownServiceError:
+            endpoints_ruleset_data = None
+            partition_data = None
+            logger.info(
+                'No endpoints ruleset found for service %s, falling back to '
+                'legacy endpoint routing.',
+                service_name,
+            )
+        return service_model, endpoints_ruleset_data, partition_data
+
     async def _create_client_class(self, service_name, service_model):
         class_attributes = self._create_methods(service_model)
         py_name_to_operation_name = self._create_name_mapping(service_model)

aiobotocore/session.py

@@ -1,7 +1,12 @@
+import asyncio
+import functools
+
 from botocore import UNSIGNED
 from botocore import __version__ as botocore_version
 from botocore import translate
+from botocore.client import logger
 from botocore.exceptions import PartialCredentialsError
+from botocore.loaders import Loader
 from botocore.session import EVENT_ALIASES, ServiceModel
 from botocore.session import Session as _SyncSession
 from botocore.session import UnknownServiceError, copy
@@ -37,6 +42,7 @@ def __init__(
         event_hooks=None,
         include_builtin_handlers=True,
         profile=None,
+        load_executor=False,
     ):
         if event_hooks is None:
             event_hooks = AioHierarchicalEmitter()
@@ -46,6 +52,7 @@ def __init__(
         )
 
         self._set_user_agent_for_session()
+        self.load_executor = load_executor
 
     def _set_user_agent_for_session(self):
         # Mimic approach taken by AWS's aws-cli project
@@ -103,9 +110,25 @@ async def get_service_data(self, service_name, api_version=None):
         Retrieve the fully merged data associated with a service.
         """
         data_path = service_name
-        service_data = self.get_component('data_loader').load_service_model(
-            data_path, type_name='service-2', api_version=api_version
+        data_loader: Loader = self.get_component('data_loader')
+        logger.debug(
+            "AioSession - Method load_service_model[botocore] could generate I/O. Running in executor: %s",
+            self.load_executor,
         )
+        if self.load_executor:
+            service_data = await asyncio.get_event_loop().run_in_executor(
+                None,
+                functools.partial(
+                    data_loader.load_service_model,
+                    data_path,
+                    type_name='service-2',
+                    api_version=api_version,
+                ),
+            )
+        else:
+            service_data = data_loader.load_service_model(
+                data_path, type_name='service-2', api_version=api_version
+            )
         service_id = EVENT_ALIASES.get(service_name, service_name)
         await self._events.emit(
             f'service-data-loaded.{service_id}',
@@ -223,6 +246,7 @@ async def _create_client(
             client_config=config,
             api_version=api_version,
             auth_token=auth_token,
+            load_executor=self.load_executor,
         )
         monitor = self._get_internal_component('monitor')
         if monitor is not None: