CASMCMS-9225: Create generic API client class

constraints.txt.in

@@ -37,7 +37,7 @@ PyYAML>=6.0.1,<6.1
 redis>=5.0,<5.1
 requests>=2.28.2,<2.29
 requests-oauthlib>=1.3.1,<1.4
-requests-retry-session>=0.1,<0.2
+requests-retry-session>=2.0,<2.1
 retrying>=1.3.4,<1.4
 rsa>=4.9,<4.10
 s3transfer>=0.6.2,<0.7

requirements.txt

@@ -15,7 +15,7 @@ python-dateutil
 PyYAML
 redis
 requests
-requests-retry-session
+requests-retry-session>=2.0
 urllib3
 
 # The purpose of this file is to contain python runtime requirements

src/bos/common/clients/api_client.py

@@ -0,0 +1,62 @@
+#
+# MIT License
+#
+# (C) Copyright 2021-2024 Hewlett Packard Enterprise Development LP
+#
+# Permission is hereby granted, free of charge, to any person obtaining a
+# copy of this software and associated documentation files (the "Software"),
+# to deal in the Software without restriction, including without limitation
+# the rights to use, copy, modify, merge, publish, distribute, sublicense,
+# and/or sell copies of the Software, and to permit persons to whom the
+# Software is furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+# OTHER DEALINGS IN THE SOFTWARE.
+#
+from abc import ABC
+from typing import Type, TypeVar
+
+from bos.common.clients.endpoints import BaseGenericEndpoint
+from bos.common.utils import RetrySessionManager
+
+ClientEndpoint = TypeVar('ClientEndpoint', bound=BaseGenericEndpoint)
+
+
+class APIClient(RetrySessionManager, ABC):
+    """
+    As a subclass of RetrySessionManager, this class can be used as a context manager,
+    and will have a requests session available as self.requests_session
+
+    This context manager is used to provide API endpoints, via subclassing.
+    """
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self._endpoint_values: dict[Type[ClientEndpoint], ClientEndpoint] = {}
+
+    def get_endpoint(self,
+                     endpoint_type: Type[ClientEndpoint]) -> ClientEndpoint:
+        """
+        Endpoints are created only as needed, and passed the managed retry session.
+        """
+        if endpoint_type not in self._endpoint_values:
+            self._endpoint_values[endpoint_type] = endpoint_type(
+                self.requests_session)
+        return self._endpoint_values[endpoint_type]
+
+    def __exit__(self, exc_type, exc_val, exc_tb) -> bool | None:
+        """
+        The only cleanup we need to do when exiting the context manager is to clear out
+        our list of API clients. Our call to super().__exit__ will take care of closing
+        out the underlying request session.
+        """
+        self._endpoint_values.clear()
+        return super().__exit__(exc_type, exc_val, exc_tb)

src/bos/common/utils.py

@@ -31,7 +31,7 @@
 
 # Third party imports
 from dateutil.parser import parse
-from requests_retry_session import requests_retry_session as base_requests_retry_session
+import requests_retry_session as rrs
 
 PROTOCOL = 'http'
 TIME_DURATION_PATTERN = re.compile(r"^(\d+?)(\D+?)$", re.M | re.S)
@@ -68,14 +68,32 @@ def duration_to_timedelta(timestamp: str):
     return datetime.timedelta(seconds=seconds)
 
 
-requests_retry_session = partial(base_requests_retry_session,
-                                 retries=10,
-                                 backoff_factor=0.5,
-                                 status_forcelist=(500, 502, 503, 504),
-                                 connect_timeout=3,
-                                 read_timeout=10,
+DEFAULT_RETRY_ADAPTER_ARGS = rrs.RequestsRetryAdapterArgs(
+    retries=10,
+    backoff_factor=0.5,
+    status_forcelist=(500, 502, 503, 504),
+    connect_timeout=3,
+    read_timeout=10)
+
+
+class RetrySessionManager(rrs.RetrySessionManager):
+    """
+    Just sets the default values we use for our requests sessions
+    """
+
+    def __init__(self,
+                 protocol: str = PROTOCOL,
+                 **adapter_kwargs: Unpack[rrs.RequestsRetryAdapterArgs]):
+        for key, value in DEFAULT_RETRY_ADAPTER_ARGS.items():
+            if key not in adapter_kwargs:
+                adapter_kwargs[key] = value
+        super().__init__(protocol=protocol, **adapter_kwargs)
+
+
+requests_retry_session = partial(rrs.requests_retry_session,                                 
                                  session=None,
-                                 protocol=PROTOCOL)
+                                 protocol=PROTOCOL,
+                                 **DEFAULT_RETRY_ADAPTER_ARGS)
 
 
 def compact_response_text(response_text: str) -> str: