cache: updated cache decorators based on latest code from dogpile

vcsserver/lib/rc_cache/utils.py

@@ -1,151 +1,153 b''
 # RhodeCode VCSServer provides access to different vcs backends via network.
 # Copyright (C) 2014-2019 RhodeCode GmbH
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation; either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
 
 import os
 import logging
 import functools
+from decorator import decorate
 
 from dogpile.cache import CacheRegion
 from dogpile.cache.util import compat
 
 from vcsserver.utils import safe_str, sha1
 
 
 log = logging.getLogger(__name__)
 
 
 class RhodeCodeCacheRegion(CacheRegion):
 
     def conditional_cache_on_arguments(
             self, namespace=None,
             expiration_time=None,
             should_cache_fn=None,
             to_str=compat.string_type,
             function_key_generator=None,
             condition=True):
         """
         Custom conditional decorator, that will not touch any dogpile internals if
         condition isn't meet. This works a bit different than should_cache_fn
         And it's faster in cases we don't ever want to compute cached values
         """
         expiration_time_is_callable = compat.callable(expiration_time)
 
         if function_key_generator is None:
             function_key_generator = self.function_key_generator
 
-        def decorator(fn):
-            if to_str is compat.string_type:
-                # backwards compatible
-                key_generator = function_key_generator(namespace, fn)
-            else:
-                key_generator = function_key_generator(namespace, fn, to_str=to_str)
-
-            @functools.wraps(fn)
-            def decorate(*arg, **kw):
-                key = key_generator(*arg, **kw)
-
-                @functools.wraps(fn)
-                def creator():
-                    return fn(*arg, **kw)
+        def get_or_create_for_user_func(key_generator, user_func, *arg, **kw):
 
                 if not condition:
-                    log.debug('Calling un-cached func:%s', fn)
-                    return creator()
+                log.debug('Calling un-cached func:%s', user_func)
+                return user_func(*arg, **kw)
+
+            key = key_generator(*arg, **kw)
 
                 timeout = expiration_time() if expiration_time_is_callable \
                     else expiration_time
 
-                log.debug('Calling cached fn:%s', fn)
-                return self.get_or_create(key, creator, timeout, should_cache_fn)
+            log.debug('Calling cached fn:%s', user_func)
+            return self.get_or_create(key, user_func, timeout, should_cache_fn, (arg, kw))
+
+        def cache_decorator(user_func):
+            if to_str is compat.string_type:
+                # backwards compatible
+                key_generator = function_key_generator(namespace, user_func)
+            else:
+                key_generator = function_key_generator(namespace, user_func, to_str=to_str)
+
+            def refresh(*arg, **kw):
+                """
+                Like invalidate, but regenerates the value instead
+                """
+                key = key_generator(*arg, **kw)
+                value = user_func(*arg, **kw)
+                self.set(key, value)
+                return value
 
             def invalidate(*arg, **kw):
                 key = key_generator(*arg, **kw)
                 self.delete(key)
 
             def set_(value, *arg, **kw):
                 key = key_generator(*arg, **kw)
                 self.set(key, value)
 
             def get(*arg, **kw):
                 key = key_generator(*arg, **kw)
                 return self.get(key)
 
-            def refresh(*arg, **kw):
-                key = key_generator(*arg, **kw)
-                value = fn(*arg, **kw)
-                self.set(key, value)
-                return value
+            user_func.set = set_
+            user_func.invalidate = invalidate
+            user_func.get = get
+            user_func.refresh = refresh
+            user_func.key_generator = key_generator
+            user_func.original = user_func
 
-            decorate.set = set_
-            decorate.invalidate = invalidate
-            decorate.refresh = refresh
-            decorate.get = get
-            decorate.original = fn
-            decorate.key_generator = key_generator
-            decorate.__wrapped__ = fn
+            # Use `decorate` to preserve the signature of :param:`user_func`.
 
-            return decorate
+            return decorate(user_func, functools.partial(
+                get_or_create_for_user_func, key_generator))
 
-        return decorator
+        return cache_decorator
 
 
 def make_region(*arg, **kw):
     return RhodeCodeCacheRegion(*arg, **kw)
 
 
 def get_default_cache_settings(settings, prefixes=None):
     prefixes = prefixes or []
     cache_settings = {}
     for key in settings.keys():
         for prefix in prefixes:
             if key.startswith(prefix):
                 name = key.split(prefix)[1].strip()
                 val = settings[key]
                 if isinstance(val, compat.string_types):
                     val = val.strip()
                 cache_settings[name] = val
     return cache_settings
 
 
 def compute_key_from_params(*args):
     """
     Helper to compute key from given params to be used in cache manager
     """
     return sha1("_".join(map(safe_str, args)))
 
 
 def backend_key_generator(backend):
     """
     Special wrapper that also sends over the backend to the key generator
     """
     def wrapper(namespace, fn):
         return key_generator(backend, namespace, fn)
     return wrapper
 
 
 def key_generator(backend, namespace, fn):
     fname = fn.__name__
 
     def generate_key(*args):
         backend_prefix = getattr(backend, 'key_prefix', None) or 'backend_prefix'
         namespace_pref = namespace or 'default_namespace'
         arg_key = compute_key_from_params(*args)
         final_key = "{}:{}:{}_{}".format(backend_prefix, namespace_pref, fname, arg_key)
 
         return final_key
 
     return generate_key