skip cashing for exceptions (#233)

* adding test

* _print

* cleaning

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* with completed

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

src/cachier/config.py

@@ -46,8 +46,9 @@ class CacheEntry:
     value: Any
     time: datetime
     stale: bool
-    being_calculated: bool
-    condition: Optional[threading.Condition] = None
+    _processing: bool
+    _condition: Optional[threading.Condition] = None
+    _completed: bool = False
 
 
 def _update_with_defaults(

src/cachier/core.py

@@ -14,7 +14,7 @@
 from collections import OrderedDict
 from concurrent.futures import ThreadPoolExecutor
 from functools import wraps
-from typing import Optional, Union
+from typing import Any, Optional, Union
 from warnings import warn
 
 from .config import (
@@ -55,13 +55,11 @@ def _function_thread(core, key, func, args, kwds):
         print(f"Function call failed with the following exception:\n{exc}")
 
 
-def _calc_entry(core, key, func, args, kwds):
+def _calc_entry(core, key, func, args, kwds) -> Optional[Any]:
+    core.mark_entry_being_calculated(key)
     try:
-        core.mark_entry_being_calculated(key)
-        # _get_executor().submit(core.mark_entry_being_calculated, key)
         func_res = func(*args, **kwds)
         core.set_entry(key, func_res)
-        # _get_executor().submit(core.set_entry, key, func_res)
         return func_res
     finally:
         core.mark_entry_not_calculated(key)
@@ -242,9 +240,8 @@ def func_wrapper(*args, **kwds):
                 func, _is_method=core.func_is_method, args=args, kwds=kwds
             )
 
-            _print = lambda x: None  # noqa: E731
-            if verbose:
-                _print = print
+            _print = print if verbose else lambda x: None
+
             if ignore_cache or not _global_params.caching_enabled:
                 return (
                     func(args[0], **kwargs)
@@ -254,7 +251,9 @@ def func_wrapper(*args, **kwds):
             key, entry = core.get_entry((), kwargs)
             if overwrite_cache:
                 return _calc_entry(core, key, func, args, kwds)
-            if entry is None:
+            if entry is None or (
+                not entry._completed and not entry._processing
+            ):
                 _print("No entry found. No current calc. Calling like a boss.")
                 return _calc_entry(core, key, func, args, kwds)
             _print("Entry found.")
@@ -265,7 +264,7 @@ def func_wrapper(*args, **kwds):
                     _print("And it is fresh!")
                     return entry.value
                 _print("But it is stale... :(")
-                if entry.being_calculated:
+                if entry._processing:
                     if _next_time:
                         _print("Returning stale.")
                         return entry.value  # return stale val
@@ -276,8 +275,8 @@ def func_wrapper(*args, **kwds):
                         return _calc_entry(core, key, func, args, kwds)
                 if _next_time:
                     _print("Async calc and return stale")
+                    core.mark_entry_being_calculated(key)
                     try:
-                        core.mark_entry_being_calculated(key)
                         _get_executor().submit(
                             _function_thread, core, key, func, args, kwds
                         )
@@ -286,7 +285,7 @@ def func_wrapper(*args, **kwds):
                     return entry.value
                 _print("Calling decorated function and waiting")
                 return _calc_entry(core, key, func, args, kwds)
-            if entry.being_calculated:
+            if entry._processing:
                 _print("No value but being calculated. Waiting.")
                 try:
                     return core.wait_on_entry_calc(key)

src/cachier/cores/memory.py

@@ -26,61 +26,65 @@ def get_entry_by_key(
             return key, self.cache.get(self._hash_func_key(key), None)
 
     def set_entry(self, key: str, func_res: Any) -> None:
+        hash_key = self._hash_func_key(key)
         with self.lock:
             try:
                 # we need to retain the existing condition so that
                 # mark_entry_not_calculated can notify all possibly-waiting
                 # threads about it
-                cond = self.cache[self._hash_func_key(key)].condition
+                cond = self.cache[hash_key]._condition
             except KeyError:  # pragma: no cover
                 cond = None
-            self.cache[self._hash_func_key(key)] = CacheEntry(
+            self.cache[hash_key] = CacheEntry(
                 value=func_res,
                 time=datetime.now(),
                 stale=False,
-                being_calculated=False,
-                condition=cond,
+                _processing=False,
+                _condition=cond,
+                _completed=True,
             )
 
     def mark_entry_being_calculated(self, key: str) -> None:
         with self.lock:
             condition = threading.Condition()
+            hash_key = self._hash_func_key(key)
+            if hash_key in self.cache:
+                self.cache[hash_key]._processing = True
+                self.cache[hash_key]._condition = condition
             # condition.acquire()
-            try:
-                self.cache[self._hash_func_key(key)].being_calculated = True
-                self.cache[self._hash_func_key(key)].condition = condition
-            except KeyError:
-                self.cache[self._hash_func_key(key)] = CacheEntry(
+            else:
+                self.cache[hash_key] = CacheEntry(
                     value=None,
                     time=datetime.now(),
                     stale=False,
-                    being_calculated=True,
-                    condition=condition,
+                    _processing=True,
+                    _condition=condition,
                 )
 
     def mark_entry_not_calculated(self, key: str) -> None:
+        hash_key = self._hash_func_key(key)
         with self.lock:
-            try:
-                entry = self.cache[self._hash_func_key(key)]
-            except KeyError:  # pragma: no cover
+            if hash_key not in self.cache:
                 return  # that's ok, we don't need an entry in that case
-            entry.being_calculated = False
-            cond = entry.condition
+            entry = self.cache[hash_key]
+            entry._processing = False
+            cond = entry._condition
             if cond:
                 cond.acquire()
                 cond.notify_all()
                 cond.release()
-                entry.condition = None
+                entry._condition = None
 
     def wait_on_entry_calc(self, key: str) -> Any:
+        hash_key = self._hash_func_key(key)
         with self.lock:  # pragma: no cover
-            entry = self.cache[self._hash_func_key(key)]
-            if not entry.being_calculated:
+            entry = self.cache[hash_key]
+            if not entry._processing:
                 return entry.value
-        entry.condition.acquire()
-        entry.condition.wait()
-        entry.condition.release()
-        return self.cache[self._hash_func_key(key)].value
+        entry._condition.acquire()
+        entry._condition.wait()
+        entry._condition.release()
+        return self.cache[hash_key].value
 
     def clear_cache(self) -> None:
         with self.lock:
@@ -89,5 +93,5 @@ def clear_cache(self) -> None:
     def clear_being_calculated(self) -> None:
         with self.lock:
             for entry in self.cache.values():
-                entry.being_calculated = False
-                entry.condition = None
+                entry._processing = False
+                entry._condition = None

src/cachier/cores/mongo.py

@@ -73,20 +73,14 @@ def get_entry_by_key(self, key: str) -> Tuple[str, Optional[CacheEntry]]:
         )
         if not res:
             return key, None
-        try:
-            entry = CacheEntry(
-                value=pickle.loads(res["value"]),  # noqa: S301
-                time=res.get("time", None),
-                stale=res.get("stale", False),
-                being_calculated=res.get("being_calculated", False),
-            )
-        except KeyError:
-            entry = CacheEntry(
-                value=None,
-                time=res.get("time", None),
-                stale=res.get("stale", False),
-                being_calculated=res.get("being_calculated", False),
-            )
+        val = pickle.loads(res["value"]) if "value" in res else None  # noqa: S301
+        entry = CacheEntry(
+            value=val,
+            time=res.get("time", None),
+            stale=res.get("stale", False),
+            _processing=res.get("processing", False),
+            _completed=res.get("completed", False),
+        )
         return key, entry
 
     def set_entry(self, key: str, func_res: Any) -> None:
@@ -100,7 +94,8 @@ def set_entry(self, key: str, func_res: Any) -> None:
                     "value": Binary(thebytes),
                     "time": datetime.now(),
                     "stale": False,
-                    "being_calculated": False,
+                    "processing": False,
+                    "completed": True,
                 }
             },
             upsert=True,
@@ -109,7 +104,7 @@ def set_entry(self, key: str, func_res: Any) -> None:
     def mark_entry_being_calculated(self, key: str) -> None:
         self.mongo_collection.update_one(
             filter={"func": self._func_str, "key": key},
-            update={"$set": {"being_calculated": True}},
+            update={"$set": {"processing": True}},
             upsert=True,
         )
 
@@ -120,7 +115,7 @@ def mark_entry_not_calculated(self, key: str) -> None:
                     "func": self._func_str,
                     "key": key,
                 },
-                update={"$set": {"being_calculated": False}},
+                update={"$set": {"processing": False}},
                 upsert=False,  # should not insert in this case
             )
 
@@ -132,7 +127,7 @@ def wait_on_entry_calc(self, key: str) -> Any:
             key, entry = self.get_entry_by_key(key)
             if entry is None:
                 raise RecalculationNeeded()
-            if not entry.being_calculated:
+            if not entry._processing:
                 return entry.value
             self.check_calc_timeout(time_spent)
 
@@ -143,7 +138,7 @@ def clear_being_calculated(self) -> None:
         self.mongo_collection.update_many(
             filter={
                 "func": self._func_str,
-                "being_calculated": True,
+                "processing": True,
             },
-            update={"$set": {"being_calculated": False}},
+            update={"$set": {"processing": False}},
         )

src/cachier/cores/pickle.py

@@ -46,17 +46,14 @@ def inject_observer(self, observer) -> None:
             self.observer = observer
 
         def _check_calculation(self) -> None:
-            # print('checking calc')
             entry = self.core.get_entry_by_key(self.key, True)[1]
-            # print(self.key)
-            # print(entry)
             try:
-                if not entry.being_calculated:
+                if not entry._processing:
                     # print('stopping observer!')
                     self.value = entry.value
                     self.observer.stop()
                 # else:
-                # print('NOT stopping observer... :(')
+                #     print('NOT stopping observer... :(')
             except TypeError:
                 self.value = None
                 self.observer.stop()
@@ -169,7 +166,8 @@ def set_entry(self, key: str, func_res: Any) -> None:
             value=func_res,
             time=datetime.now(),
             stale=False,
-            being_calculated=False,
+            _processing=False,
+            _completed=True,
         )
         if self.separate_files:
             self._save_cache(key_data, key)
@@ -186,14 +184,14 @@ def mark_entry_being_calculated_separate_files(self, key: str) -> None:
                 value=None,
                 time=datetime.now(),
                 stale=False,
-                being_calculated=True,
+                _processing=True,
             ),
             key=key,
         )
 
     def mark_entry_not_calculated_separate_files(self, key: str) -> None:
         _, entry = self.get_entry_by_key(key)
-        entry.being_calculated = False
+        entry._processing = False
         self._save_cache(entry, key=key)
 
     def mark_entry_being_calculated(self, key: str) -> None:
@@ -203,14 +201,14 @@ def mark_entry_being_calculated(self, key: str) -> None:
 
         with self.lock:
             cache = self._get_cache()
-            try:
-                cache[key].being_calculated = True
-            except KeyError:
+            if key in cache:
+                cache[key]._processing = True
+            else:
                 cache[key] = CacheEntry(
                     value=None,
                     time=datetime.now(),
                     stale=False,
-                    being_calculated=True,
+                    _processing=True,
                 )
             self._save_cache(cache)
 
@@ -221,7 +219,7 @@ def mark_entry_not_calculated(self, key: str) -> None:
             cache = self._get_cache()
             # that's ok, we don't need an entry in that case
             if isinstance(cache, dict) and key in cache:
-                cache[key].being_calculated = False
+                cache[key]._processing = False
                 self._save_cache(cache)
 
     def wait_on_entry_calc(self, key: str) -> Any:
@@ -233,7 +231,7 @@ def wait_on_entry_calc(self, key: str) -> Any:
                 self._reload_cache()
                 entry = self._get_cache()[key]
             filename = self.cache_fname
-        if not entry.being_calculated:
+        if not entry._processing:
             return entry.value
         event_handler = _PickleCore.CacheChangeHandler(
             filename=filename, core=self, key=key
@@ -263,5 +261,5 @@ def clear_being_calculated(self) -> None:
         with self.lock:
             cache = self._get_cache()
             for key in cache:
-                cache[key].being_calculated = False
+                cache[key]._processing = False
             self._save_cache(cache)

tests/test_general.py

@@ -492,3 +492,15 @@ def fn_minus(a, b=2):
 
     assert count_p == 1
     assert count_m == 1
+
+
+@pytest.mark.parametrize("backend", ["memory", "pickle"])
+def test_raise_exception(tmpdir, backend: str):
+    @cachier.cachier(cache_dir=tmpdir, backend=backend, allow_none=True)
+    def tmp_test(_):
+        raise RuntimeError("always raise")
+
+    with pytest.raises(RuntimeError):
+        tmp_test(123)
+    with pytest.raises(RuntimeError):
+        tmp_test(123)

tests/test_mongo_core.py

@@ -275,7 +275,7 @@ def _stalled_func():
 def test_stalled_mong_db_core(monkeypatch):
     def mock_get_entry(self, args, kwargs):
         return "key", CacheEntry(
-            being_calculated=True, value=None, time=None, stale=None
+            _processing=True, value=None, time=None, stale=None
         )
 
     def mock_get_entry_by_key(self, key):
@@ -300,7 +300,7 @@ def mock_get_entry_2(self, args, kwargs):
         return "key", CacheEntry(
             value=1,
             time=datetime.datetime.now() - datetime.timedelta(seconds=10),
-            being_calculated=True,
+            _processing=True,
             stale=None,
         )