76620e0bf2
This adds middleware that will create custom parameter metrics in New Relic to track the size of all the cookies being received for our domain. The custom fields are "cookies_total_size" and a separate named parameter for every cookie size, e.g. "cookies.csrftoken.size". This is intended to help us track cookie growth and better diagnose issues where users lose their sessions. It is toggled by the 'request_utils.capture_cookie_sizes' Waffle Flag.
127 lines
4.0 KiB
Python
127 lines
4.0 KiB
Python
""" Utility functions related to HTTP requests """
|
|
import logging
|
|
import re
|
|
from urlparse import urlparse
|
|
|
|
import crum
|
|
from django.conf import settings
|
|
from django.utils.deprecation import MiddlewareMixin
|
|
from django.test.client import RequestFactory
|
|
|
|
from openedx.core.djangoapps.waffle_utils import WaffleFlag, WaffleFlagNamespace
|
|
from opaque_keys import InvalidKeyError
|
|
from opaque_keys.edx.keys import CourseKey
|
|
from openedx.core.djangoapps.site_configuration import helpers as configuration_helpers
|
|
|
|
try:
|
|
import newrelic.agent
|
|
except ImportError:
|
|
newrelic = None # pylint: disable=invalid-name
|
|
|
|
# accommodates course api urls, excluding any course api routes that do not fall under v*/courses, such as v1/blocks.
|
|
COURSE_REGEX = re.compile(r'^(.*?/courses/)(?!v[0-9]+/[^/]+){}'.format(settings.COURSE_ID_PATTERN))
|
|
|
|
WAFFLE_FLAG_NAMESPACE = WaffleFlagNamespace(name='request_utils')
|
|
CAPTURE_COOKIE_SIZES = WaffleFlag(WAFFLE_FLAG_NAMESPACE, 'capture_cookie_sizes')
|
|
log = logging.getLogger(__name__)
|
|
|
|
|
|
def get_request_or_stub():
|
|
"""
|
|
Return the current request or a stub request.
|
|
|
|
If called outside the context of a request, construct a fake
|
|
request that can be used to build an absolute URI.
|
|
|
|
This is useful in cases where we need to pass in a request object
|
|
but don't have an active request (for example, in tests, celery tasks, and XBlocks).
|
|
"""
|
|
request = crum.get_current_request()
|
|
|
|
if request is None:
|
|
|
|
# The settings SITE_NAME may contain a port number, so we need to
|
|
# parse the full URL.
|
|
full_url = "http://{site_name}".format(site_name=settings.SITE_NAME)
|
|
parsed_url = urlparse(full_url)
|
|
|
|
# Construct the fake request. This can be used to construct absolute
|
|
# URIs to other paths.
|
|
return RequestFactory(
|
|
SERVER_NAME=parsed_url.hostname,
|
|
SERVER_PORT=parsed_url.port or 80,
|
|
).get("/")
|
|
|
|
else:
|
|
return request
|
|
|
|
|
|
def safe_get_host(request):
|
|
"""
|
|
Get the host name for this request, as safely as possible.
|
|
|
|
If ALLOWED_HOSTS is properly set, this calls request.get_host;
|
|
otherwise, this returns whatever settings.SITE_NAME is set to.
|
|
|
|
This ensures we will never accept an untrusted value of get_host()
|
|
"""
|
|
if isinstance(settings.ALLOWED_HOSTS, (list, tuple)) and '*' not in settings.ALLOWED_HOSTS:
|
|
return request.get_host()
|
|
else:
|
|
return configuration_helpers.get_value('site_domain', settings.SITE_NAME)
|
|
|
|
|
|
def course_id_from_url(url):
|
|
"""
|
|
Extracts the course_id from the given `url`.
|
|
"""
|
|
if not url:
|
|
return None
|
|
|
|
match = COURSE_REGEX.match(url)
|
|
|
|
if match is None:
|
|
return None
|
|
|
|
course_id = match.group('course_id')
|
|
|
|
if course_id is None:
|
|
return None
|
|
|
|
try:
|
|
return CourseKey.from_string(course_id)
|
|
except InvalidKeyError:
|
|
return None
|
|
|
|
|
|
class CookieMetricsMiddleware(MiddlewareMixin):
|
|
"""
|
|
Middleware for monitoring the size and growth of all our cookies, to see if
|
|
we're running into browser limits.
|
|
"""
|
|
def process_request(self, request):
|
|
"""
|
|
Emit custom metrics for cookie size values for every cookie we have.
|
|
|
|
Don't log contents of cookies because that might cause a security issue.
|
|
We just want to see if any cookies are growing out of control.
|
|
"""
|
|
if not newrelic:
|
|
return
|
|
|
|
if not CAPTURE_COOKIE_SIZES.is_enabled():
|
|
return
|
|
|
|
cookie_names_to_size = {
|
|
name: len(value)
|
|
for name, value in request.COOKIES.items()
|
|
}
|
|
for name, size in cookie_names_to_size.items():
|
|
metric_name = 'cookies.{}.size'.format(name)
|
|
newrelic.agent.add_custom_parameter(metric_name, size)
|
|
log.debug("%s = %d", metric_name, size)
|
|
|
|
total_cookie_size = sum(cookie_names_to_size.values())
|
|
newrelic.agent.add_custom_parameter('cookies_total_size', total_cookie_size)
|
|
log.debug("cookies_total_size = %d", total_cookie_size)
|