Manually calculate cache key as getcallargs is expensive

This is because getcallargs recomputes the getargspec, amongst other
things, which we don't need to do as its already been done
This commit is contained in:
Erik Johnston 2017-03-28 11:14:15 +01:00
parent 86780a8bc3
commit 014fee93b3

View File

@ -197,6 +197,7 @@ class _CacheDescriptorBase(object):
arg_spec = inspect.getargspec(orig)
all_args = arg_spec.args
self.arg_spec = arg_spec
if "cache_context" in all_args:
if not cache_context:
@ -226,6 +227,14 @@ class _CacheDescriptorBase(object):
self.num_args = num_args
self.arg_names = all_args[1:num_args + 1]
if arg_spec.defaults:
self.arg_defaults = dict(zip(
all_args[-len(arg_spec.defaults):],
arg_spec.defaults
))
else:
self.arg_defaults = {}
if "cache_context" in self.arg_names:
raise Exception(
"cache_context arg cannot be included among the cache keys"
@ -289,18 +298,31 @@ class CacheDescriptor(_CacheDescriptorBase):
iterable=self.iterable,
)
def get_cache_key(args, kwargs):
"""Given some args/kwargs return a generator that resolves into
the cache_key.
We loop through each arg name, looking up if its in the `kwargs`,
otherwise using the next argument in `args`. If there are no more
args then we try looking the arg name up in the defaults
"""
pos = 0
for nm in self.arg_names:
if nm in kwargs:
yield kwargs[nm]
elif pos < len(args):
yield args[pos]
pos += 1
else:
yield self.arg_defaults[nm]
@functools.wraps(self.orig)
def wrapped(*args, **kwargs):
# If we're passed a cache_context then we'll want to call its invalidate()
# whenever we are invalidated
invalidate_callback = kwargs.pop("on_invalidate", None)
# Add temp cache_context so inspect.getcallargs doesn't explode
if self.add_cache_context:
kwargs["cache_context"] = None
arg_dict = inspect.getcallargs(self.orig, obj, *args, **kwargs)
cache_key = tuple(arg_dict[arg_nm] for arg_nm in self.arg_names)
cache_key = tuple(get_cache_key(args, kwargs))
# Add our own `cache_context` to argument list if the wrapped function
# has asked for one