refresh / python 3.8 / 1.3.0

do a full bump of everything, flake8, black etc.
and get minimum version on python 3.8.  pep-621
also enabled as this is very standard now.  Also pifpaf
requires pkg_resources which was removed from python 3.12
so do some rearrangement to get that in the dependencies.
Fix really old and sort of pointless(?) test that loads the
"mako" entrypoint to use importlib.metadata (standard
as of Python 3.8, so we're good).

Apply a hardening of the distributed lock for memcached,
using a mutex when calling client.add() so that multiple
threads calling on this python method are also synchronized

Change-Id: Ic3986070e21c84cdea12d8cfa01cc353f21adf0f

Author: zzzeek

.pre-commit-config.yaml

@@ -2,7 +2,7 @@
 # See https://pre-commit.com/hooks.html for more hooks
 repos:
 -   repo: https://github.com/python/black
-    rev: 22.3.0
+    rev: 23.12.0
     hooks:
     -   id: black
 
@@ -14,14 +14,18 @@ repos:
             - --keep-unused-type-checking
 
 -   repo: https://github.com/pycqa/flake8
-    rev: 4.0.1
+    rev: 6.1.0
     hooks:
     -   id: flake8
         additional_dependencies:
           - flake8-import-order
+          - flake8-import-single==0.1.5
           - flake8-builtins
+          - flake8-future-annotations>=0.0.5
           - flake8-docstrings>=1.6.0
+          - flake8-unused-arguments
           - flake8-rst-docstrings
+          # flake8-rst-docstrings dependency, leaving it here
+          # in case it requires a version pin
           - pydocstyle
           - pygments
-

docs/build/changelog.rst

@@ -3,7 +3,7 @@ Changelog
 =========
 
 .. changelog::
-    :version: 1.2.3
+    :version: 1.3.0
     :include_notes_from: unreleased
 
 .. changelog::

docs/build/unreleased/38.rst

@@ -0,0 +1,11 @@
+.. change::
+    :tags: change, setup
+
+    Minimum Python version is now Python 3.8; prior versions Python 3.7 and 3.6
+    are EOL.
+
+
+.. change::
+    :tags: change, setup
+
+    Project setup is now based on pep-621 ``pyproject.toml`` configuration.

dogpile/__init__.py

@@ -1,4 +1,4 @@
-__version__ = "1.2.3"
+__version__ = "1.3.0"
 
 from .lock import Lock  # noqa
 from .lock import NeedRegenerationException  # noqa

dogpile/cache/api.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import abc
 import pickle
 from typing import Any

dogpile/cache/backends/memcached.py

@@ -41,25 +41,27 @@
 )
 
 
-class MemcachedLock(object):
+class MemcachedLock:
     """Simple distributed lock using memcached."""
 
     def __init__(self, client_fn, key, timeout=0):
         self.client_fn = client_fn
         self.key = "_lock" + key
         self.timeout = timeout
+        self._mutex = threading.Lock()
 
     def acquire(self, wait=True):
         client = self.client_fn()
         i = 0
         while True:
-            if client.add(self.key, 1, self.timeout):
-                return True
-            elif not wait:
-                return False
-            else:
-                sleep_time = (((i + 1) * random.random()) + 2**i) / 2.5
-                time.sleep(sleep_time)
+            with self._mutex:
+                if client.add(self.key, 1, self.timeout):
+                    return True
+                elif not wait:
+                    return False
+
+            sleep_time = (((i + 1) * random.random()) + 2**i) / 2.5
+            time.sleep(sleep_time)
             if i < 15:
                 i += 1
 

dogpile/cache/proxy.py

@@ -9,6 +9,9 @@
 .. versionadded:: 0.5.0  Added support for the :class:`.ProxyBackend` class.
 
 """
+
+from __future__ import annotations
+
 from typing import Mapping
 from typing import Optional
 from typing import Sequence

dogpile/cache/region.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import contextlib
 import datetime
 from functools import partial
@@ -897,7 +899,6 @@ def get_or_create(
         should_cache_fn: Optional[Callable[[ValuePayload], bool]] = None,
         creator_args: Optional[Tuple[Any, Mapping[str, Any]]] = None,
     ) -> ValuePayload:
-
         """Return a cached value based on the given key.
 
         If the value does not exist or is considered to be expired
@@ -1035,7 +1036,6 @@ def gen_value():
 
             def async_creator(mutex):
                 if creator_args:
-
                     ca = creator_args
 
                     @wraps(creator)

dogpile/cache/util.py

@@ -46,7 +46,6 @@ def generate_key(*args, **kw):
 
 
 def function_multi_key_generator(namespace, fn, to_str=str):
-
     if namespace is None:
         namespace = "%s:%s" % (fn.__module__, fn.__name__)
     else:
@@ -163,7 +162,6 @@ def mangle(key):
 
 
 class repr_obj:
-
     __slots__ = ("value", "max_chars")
 
     def __init__(self, value, max_chars=300):

pyproject.toml

@@ -1,3 +1,75 @@
+[build-system]
+requires = ["setuptools>=61.2"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "dogpile.cache"
+description = "A caching front-end based on the Dogpile lock."
+readme = "README.rst"
+keywords = ["caching"]
+authors = [{name = "Mike Bayer", email = "mike_mp@zzzcomputing.com"}]
+license = {text = "MIT"}
+classifiers = [
+    "Development Status :: 5 - Production/Stable",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: MIT License",
+    "Programming Language :: Python",
+    "Programming Language :: Python :: 3",
+]
+requires-python = ">=3.8"
+dependencies = [
+    "decorator>=4.0.0",
+    "stevedore>=3.0.0",
+    "typing_extensions>=4.0.1;python_version<'3.11'",
+]
+dynamic = ["version"]
+
+[project.urls]
+Homepage = "https://github.com/sqlalchemy/dogpile.cache"
+Documentation = "https://dogpilecache.sqlalchemy.org"
+"Issue Tracker" = "https://github.com/sqlalchemy/dogpile.cache/"
+
+[project.optional-dependencies]
+pifpaf = [
+    "pifpaf>=2.5.0",
+    "setuptools;python_version>='3.12'",
+]
+
+[project.entry-points."mako.cache"]
+"dogpile.cache" = "dogpile.cache.plugins.mako_cache:MakoPlugin"
+
+
+[tool.setuptools]
+zip-safe = false
+include-package-data = true
+package-dir = {"" = "."}
+license-files = ["LICENSE"]
+
+[tool.setuptools.packages.find]
+exclude = [
+    "tests",
+    "tests.*",
+]
+namespaces = false
+
+[tool.setuptools.exclude-package-data]
+dogpile = ["tests*"]
+
+[tool.setuptools.package-data]
+dogpile = ["py.typed"]
+
+[tool.setuptools.dynamic]
+version = {attr = "dogpile.__version__"}
+
 [tool.black]
 line-length = 79
-target-version = ['py36']
+target-version = ['py38']
+
+
+[tool.pytest.ini_options]
+addopts = "--tb native -v -r fxX  -p no:logging -p no:warnings -m 'not time_intensive'"
+python_files = "tests/*test_*.py"
+filterwarnings = [
+    "error"
+]
+