def traced_load_middleware(django, pin, func, instance, args, kwargs):
"""Patches django.core.handlers.base.BaseHandler.load_middleware to instrument all middlewares."""
settings_middleware = []
# Gather all the middleware
if getattr(django.conf.settings, "MIDDLEWARE", None):
settings_middleware += django.conf.settings.MIDDLEWARE
if getattr(django.conf.settings, "MIDDLEWARE_CLASSES", None):
settings_middleware += django.conf.settings.MIDDLEWARE_CLASSES
# Iterate over each middleware provided in settings.py
# Each middleware can either be a function or a class
for mw_path in settings_middleware:
mw = django.utils.module_loading.import_string(mw_path)
# Instrument function-based middleware
if isfunction(mw) and not iswrapped(mw):
split = mw_path.split(".")
if len(split) < 2:
continue
base = ".".join(split[:-1])
attr = split[-1]
# Function-based middleware is a factory which returns a handler function for requests.
# So instead of tracing the factory, we want to trace its returned value.
# We wrap the factory to return a traced version of the handler function.
def wrapped_factory(func, instance, args, kwargs):
# r is the middleware handler function returned from the factory
r = func(*args, **kwargs)
return wrapt.FunctionWrapper(
r,
traced_func(django, "django.middleware", resource=mw_path))
wrap(base, attr, wrapped_factory)
# Instrument class-based middleware
elif isclass(mw):
for hook in [
"process_request",
"process_response",
"process_view",
"process_template_response",
"__call__",
]:
if hasattr(mw, hook) and not iswrapped(mw, hook):
wrap(
mw, hook,
traced_func(django,
"django.middleware",
resource=mw_path + ".{0}".format(hook)))
# Do a little extra for `process_exception`
if hasattr(mw, "process_exception") and not iswrapped(
mw, "process_exception"):
res = mw_path + ".{0}".format("process_exception")
wrap(
mw, "process_exception",
traced_process_exception(django,
"django.middleware",
resource=res))
return func(*args, **kwargs)
def instrument_caches(django):
cache_backends = set([cache["BACKEND"] for cache in django.conf.settings.CACHES.values()])
for cache_path in cache_backends:
split = cache_path.split(".")
cache_module = ".".join(split[:-1])
cache_cls = split[-1]
for method in ["get", "set", "add", "delete", "incr", "decr", "get_many", "set_many", "delete_many"]:
try:
cls = django.utils.module_loading.import_string(cache_path)
# DEV: this can be removed when we add an idempotent `wrap`
if not iswrapped(cls, method):
wrap(cache_module, "{0}.{1}".format(cache_cls, method), traced_cache(django))
except Exception:
log.debug("Error instrumenting cache %r", cache_path, exc_info=True)