Allow disabling all caches (#9)

permacache/__init__.py

@@ -2,4 +2,5 @@
 from .cache_miss_error import CacheMissError, error_on_miss_global
 from .dict_function import drop_if, drop_if_equal
 from .hash import migrated_attrs, stable_hash, stringify
+from .no_cache import no_cache_global
 from .swap_unpickler import renamed_symbol_unpickler, swap_unpickler_context_manager

permacache/cache.py

@@ -5,6 +5,7 @@
 
 from appdirs import user_cache_dir
 
+from permacache.no_cache import no_cache_global
 from permacache.out_file_cache import (
     add_file_cache_info,
     do_copy_files,
@@ -38,6 +39,9 @@ def error_on_miss(self):
         return error_on_miss(self)
 
     def __call__(self, *args, **kwargs):
+        if no_cache_global.no_cache:
+            return self._run_underlying(*args, **kwargs)
+
         key = self.key_function(args, kwargs, parallel=self.parallel)
         if isinstance(key, parallel_output):
             return self.call_parallel(key.values, args, kwargs)

permacache/no_cache.py

@@ -0,0 +1,18 @@
+class no_cache_global:
+    """
+    context manager that sets the error on miss attribute globally, and the
+    resets it when the context is exited
+    """
+
+    no_cache = False
+
+    def __init__(self):
+        self.old = None
+
+    def __enter__(self):
+        self.old = no_cache_global.no_cache
+        no_cache_global.no_cache = True
+
+    def __exit__(self, *args):
+        assert self.old is not None
+        no_cache_global.no_cache = self.old

setup.py

@@ -5,7 +5,7 @@
 
 setuptools.setup(
     name="permacache",
-    version="3.10.0",
+    version="3.11.0",
     author="Kavi Gupta",
     author_email="[email protected]",
     description="Permanant cache.",

tests/test_cache.py

@@ -1,7 +1,7 @@
 import tempfile
 import unittest
 
-from permacache import cache
+from permacache import cache, no_cache_global
 from permacache.swap_unpickler import (
     renamed_symbol_unpickler,
     swap_unpickler_context_manager,
@@ -44,6 +44,16 @@ def test_basic(self):
         self.assertEqual(self.f(3, 2, 1, 0, -1), (3, 2, 1, (0, -1)))
         self.assertEqual(fn.counter, 3)
 
+    def test_basic_with_disabled_cache(self):
+        self.assertEqual(fn.counter, 0)
+        self.assertEqual(self.f(1, 2, 3), (1, 2, 3, ()))
+        self.assertEqual(fn.counter, 1)
+        self.assertEqual(self.f(1, 2, 3), (1, 2, 3, ()))
+        self.assertEqual(fn.counter, 1)
+        with no_cache_global():
+            self.assertEqual(self.f(1, 2, 3), (1, 2, 3, ()))
+        self.assertEqual(fn.counter, 2)
+
 
 def g(x):
     g.counter += 1