Support warm-up of loader caches

Author: jakob-keller

aiobotocore/session.py

@@ -1,3 +1,6 @@
+import asyncio
+from typing import Optional
+
 from botocore import UNSIGNED, translate
 from botocore import __version__ as botocore_version
 from botocore.context import get_context
@@ -126,6 +129,36 @@ async def get_service_data(self, service_name, api_version=None):
         )
         return service_data
 
+    def warm_up_loader_caches(
+        self,
+        service_name: str,
+        api_version: Optional[str] = None,
+    ):
+        loader = self.get_component('data_loader')
+
+        # from session.py
+        loader.load_data_with_path('endpoints')
+        loader.load_data('sdk-default-configuration')
+        loader.load_service_model(service_name, 'waiters-2', api_version)
+        loader.load_service_model(service_name, 'paginators-1', api_version)
+        loader.load_service_model(
+            service_name, type_name='service-2', api_version=api_version
+        )
+        loader.list_available_services(type_name='service-2')
+
+        # from client.py
+        loader.load_data('partitions')
+        loader.load_service_model(
+            service_name, 'service-2', api_version=api_version
+        )
+        loader.load_service_model(
+            service_name, 'endpoint-rule-set-1', api_version=api_version
+        )
+        loader.load_data('_retry')
+
+        # from docs/service.py
+        loader.load_service_model(service_name, 'examples-1', api_version)
+
     def create_client(self, *args, **kwargs):
         return ClientCreatorContext(self._create_client(*args, **kwargs))
 
@@ -167,6 +200,13 @@ async def _create_client(
             )
 
         loader = self.get_component('data_loader')
+
+        # TODO: implement config flag
+        if getattr(config, 'auto_warm_up_loader_caches'):
+            await asyncio.to_thread(
+                self.warm_up_loader_caches, service_name, api_version
+            )
+
         event_emitter = self.get_component('event_emitter')
         response_parser_factory = self.get_component('response_parser_factory')
         if config is not None and config.signature_version is UNSIGNED: