Add revalidate_fn optional param to cached_result for additional check if cache should be revalidated

.bumpversion.cfg

@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 1.9.1
+current_version = 1.9.2
 commit = False
 tag = False
 parse = (?P<major>\d+)\.(?P<minor>\d+)\.(?P<patch>\d+)(\-(?P<release>[a-z]+)(?P<build>\d+))?

nwastdlib/__init__.py

@@ -13,7 +13,7 @@
 #
 """The NWA-stdlib module."""
 
-__version__ = "1.9.1"
+__version__ = "1.9.2"
 
 from nwastdlib.f import const, identity
 

nwastdlib/asyncio_cache.py

@@ -118,6 +118,7 @@ def cached_result(
     key_name: str | None = None,
     expiry_seconds: int = 120,
     serializer: SerializerProtocol = DefaultSerializer,
+    revalidate_fn: Callable[..., bool] | None = None,
 ) -> Callable:
     """Pass returned result objects from a async function call into redis.
 
@@ -150,6 +151,7 @@ def my_other_function...
         key_name: When specified the total redis key_name will be "prefix:key_name".
         expiry_seconds: expiration in seconds. Defaults to two minutes (120s).
         serializer: Provide your own Serializer class or use the default pickle.
+        revalidate_fn: Callable function that returns bool whether to revalidate the cached result.
 
     Returns:
         decorator function
@@ -159,6 +161,8 @@ def my_other_function...
     def cache_decorator(func: Callable) -> Callable:
         @wraps(func)
         async def func_wrapper(*args: tuple[Any], **kwargs: dict[str, Any]) -> Any:
+            from_cache = (not revalidate_fn(*args, **kwargs)) if revalidate_fn else True
+
             python_major, python_minor = sys.version_info[:2]
             if key_name:
                 cache_key = f"{prefix}:{python_major}.{python_minor}:{key_name}"
@@ -169,17 +173,20 @@ async def func_wrapper(*args: tuple[Any], **kwargs: dict[str, Any]) -> Any:
                 cache_key = f"{prefix}:{python_major}.{python_minor}:{func.__name__}{args_and_kwargs_string}"
                 logger.debug("Autogenerated a cache key", cache_key=cache_key)
 
-            logger.debug("Cache called with wrapper func", func_name=func.__name__, cache_key=cache_key)
-            if secret:
-                if (cached_val := await get_signed_cache_value(pool, secret, cache_key, serializer)) is not None:
-                    logger.info("Cache contains secure key, serving from cache", func_name=func.__name__)
-                    return cached_val
+            if from_cache:
+                logger.debug("Cache called with wrapper func", func_name=func.__name__, cache_key=cache_key)
+                if secret:
+                    if (cached_val := await get_signed_cache_value(pool, secret, cache_key, serializer)) is not None:
+                        logger.info("Cache contains secure key, serving from cache", func_name=func.__name__)
+                        return cached_val
+                else:
+                    if (cached_val := await get_cache_value(pool, cache_key, serializer)) is not None:
+                        logger.info("Cache contains key, serving from cache", func_name=func.__name__)
+                        return cached_val
+                logger.info("Cache doesn't contain key, calling real function", func_name=func.__name__)
             else:
-                if (cached_val := await get_cache_value(pool, cache_key, serializer)) is not None:
-                    logger.info("Cache contains key, serving from cache", func_name=func.__name__)
-                    return cached_val
+                logger.info("ignoring cache, calling real function", func_name=func.__name__)
 
-            logger.info("Cache doesn't contain key, calling real function", func_name=func.__name__)
             result = await func(*args, **kwargs)
             if secret:
                 await set_signed_cache_value(pool, secret, cache_key, result, expiry_seconds, serializer)

setup.cfg

@@ -31,7 +31,7 @@ strict_equality = True
 
 show_error_codes = True
 show_column_numbers = True
-exclude = (benchmarks/*)
+exclude = (benchmarks/*|tests/*)
 
 ;lineprecision_report = mypy-coverage
 

tests/test_asyncio_cache.py

@@ -176,3 +176,47 @@ async def slow_function():
     # # A new call should still serve 0: as it is cached now
     result = await slow_function()
     assert result == original_value
+
+
+async def test_cache_decorator_with_revalidation_fn():
+    redis = FakeRedis()
+    value = 0
+
+    def revalidate_fn(*args, **kwargs):
+        return kwargs["revalidate_cache"]
+
+    @cached_result(redis, "test-suite", "SECRETNAME", "keyname", revalidate_fn=revalidate_fn)
+    async def slow_function(revalidate_cache: bool):
+        return value
+
+    result = await slow_function(revalidate_cache=False)
+    assert result == 0
+
+    # change the value so we can verify that the function was not called
+    value = 1
+
+    # A new call should still serve 0: as it is cached now
+    result = await slow_function(revalidate_cache=False)
+    assert result == 0
+
+
+async def test_cache_decorator_with_revalidation_fn_no_cache():
+    redis = FakeRedis()
+    value = 0
+
+    def revalidate_fn(*args, **kwargs):
+        return kwargs["revalidate_cache"]
+
+    @cached_result(redis, "test-suite", "SECRETNAME", "keyname", revalidate_fn=revalidate_fn)
+    async def slow_function(revalidate_cache: bool):
+        return value
+
+    result = await slow_function(revalidate_cache=True)
+    assert result == 0
+
+    # change the value so we can verify that the function was called
+    value = 1
+
+    # A new call should serve 1: as it is not cached now
+    result = await slow_function(revalidate_cache=True)
+    assert result == 1