Source code for oauth_dropins.webutil.instance_info
"""Renders vital stats about a single App Engine instance.
Intended for developers, not users. Uses the Runtime API:
https://developers.google.com/appengine/docs/python/backends/runtimeapi
Note that the Runtime API isn't implemented in dev_appserver, so all stats will
be reported as 0.
(The docs say it's deprecated because it's part of Backends, which is replaced
by Modules, but I haven't found a corresponding part of the Modules API.)
To turn on concurrent request recording, add the middleware and InfoHandler to your WSGI application, eg:
from oauth_dropins.webutil.instance_info import concurrent_requests_wsgi_middleware, InfoHandler
application = concurrent_requests_wsgi_middleware(webapp2.WSGIApplication([
...
('/_info', InfoHandler),
])
"""
import collections
import datetime
import heapq
import os
import threading
import webapp2
from . import handlers
CONCURRENTS_SIZE = 20
# A time when there was more than one request running at once. count is the
# first field so that instances compare by count, since they're stored in a
# heap, so that we keep the highest count instances.
Concurrent = collections.namedtuple('Concurrent', ('count', 'when'))
# globals
current_requests = set() # stores string request IDs
current_requests_lock = threading.Lock()
concurrents = [] # a heapq. stores Concurrents
[docs]class InfoHandler(handlers.TemplateHandler):
[docs] def template_file(self):
return os.path.join(os.path.dirname(__file__),
'templates/instance_info.html')
[docs] def template_vars(self):
return {'concurrents': concurrents,
'current_requests': current_requests,
'os': os,
'runtime': os.getenv('GAE_RUNTIME'),
}
[docs]def concurrent_requests_wsgi_middleware(app):
"""WSGI middleware for per request instance info instrumentation.
Follows the WSGI standard. Details: http://www.python.org/dev/peps/pep-0333/
"""
def wrapper(environ, start_response):
req_id = os.environ['REQUEST_LOG_ID']
global current_requests, current_requests_lock, concurrents
with current_requests_lock:
current_requests.add(req_id)
if len(current_requests) > 1:
heapq.heappush(concurrents, Concurrent(count=len(current_requests),
when=datetime.datetime.now()))
if len(concurrents) > CONCURRENTS_SIZE:
heapq.heappop(concurrents)
ret = app(environ, start_response)
with current_requests_lock:
current_requests.remove(req_id)
return ret
return wrapper