refactor: reuse exponential_backoff_function from hcloud-python (#535)

Replace the local function with the exponential_backoff_function from
hcloud-python

plugins/module_utils/client.py

@@ -3,7 +3,6 @@
 from __future__ import annotations
 
 from contextlib import contextmanager
-from random import random
 
 from ansible.module_utils.basic import missing_required_lib
 
@@ -107,22 +106,3 @@ class Client(ClientBase):
             yield
         finally:
             self._requests_session = requests.Session()
-
-
-def exponential_backoff_poll_interval(*, base: float, multiplier: int, cap: float, jitter: float):
-    """
-    Return a poll interval function, implementing a truncated exponential backoff with jitter.
-
-    :param base: Base for the exponential backoff algorithm.
-    :param multiplier: Multiplier for the exponential backoff algorithm.
-    :param cap: Value at which the interval is truncated.
-    :param jitter: Proportion of the interval to add as random jitter.
-    """
-
-    def func(retries: int) -> float:
-        interval = base * multiplier**retries  # Exponential backoff
-        interval = min(cap, interval)  # Cap backoff
-        interval += random() * interval * jitter  # Add jitter
-        return interval
-
-    return func

plugins/module_utils/hcloud.py

@@ -15,13 +15,13 @@ from ansible.module_utils.common.validation import (
     check_required_one_of,
 )
 
-from .client import (
+from .client import ClientException, client_check_required_lib, client_get_by_name_or_id
-    ClientException,
+from .vendor.hcloud import (
-    client_check_required_lib,
+    APIException,
-    client_get_by_name_or_id,
+    Client,
-    exponential_backoff_poll_interval,
+    HCloudException,
+    exponential_backoff_function,
 )
-from .vendor.hcloud import APIException, Client, HCloudException
 from .vendor.hcloud.actions import ActionException
 from .version import version
 
@@ -87,7 +87,7 @@ class AnsibleHCloud:
             application_name="ansible-module",
             application_version=version,
             # Total waiting time before timeout is > 117.0
-            poll_interval=exponential_backoff_poll_interval(base=1.0, multiplier=2, cap=5.0, jitter=0.5),
+            poll_interval=exponential_backoff_function(base=1.0, multiplier=2, cap=5.0),
             poll_max_retries=25,
         )
 

tests/unit/module_utils/test_client.py

@@ -1,14 +1 @@
 from __future__ import annotations
-
-from ansible_collections.hetzner.hcloud.plugins.module_utils.client import (
-    exponential_backoff_poll_interval,
-)
-
-
-def test_exponential_backoff_poll_interval():
-    poll_interval = exponential_backoff_poll_interval(base=1.0, multiplier=2, cap=5.0, jitter=0.0)
-    poll_max_retries = 25
-
-    results = [poll_interval(i) for i in range(poll_max_retries)]
-    assert sum(results) == 117.0
-    assert results[:6] == [1.0, 2.0, 4.0, 5.0, 5.0, 5.0]