I work with Django 1.7 python 2.7. In Django I have several functions. One function prepares necessary information and stores it in Redis. After that another function asynchronously starts several times, gets information from the Redis, calculates some data and returns to the client. The function runs from browser, and I have the next errors:
user_names = json.loads(cache.get(user_id))
File "/home/user/.virtualenvs/Django/local/lib/python2.7/site-packages/django_redis/cache.py", line 25, in _decorator
return method(self, *args, **kwargs)
File "/home/user/.virtualenvs/Django/local/lib/python2.7/site-packages/django_redis/cache.py", line 73, in get
client=client)
File "/home/user/.virtualenvs/Django/local/lib/python2.7/site-packages/django_redis/client/default.py", line 215, in get
value = client.get(key)
File "/home/user/.virtualenvs/Django/local/lib/python2.7/site-packages/redis/client.py", line 863, in get
return self.execute_command('GET', name)
File "/home/user/.virtualenvs/Django/local/lib/python2.7/site-packages/redis/client.py", line 565, in execute_command
return self.parse_response(connection, command_name, **options)
File "/home/user/.virtualenvs/Django/local/lib/python2.7/site-packages/redis/client.py", line 577, in parse_response
response = connection.read_response()
File "/home/user/.virtualenvs/Django/local/lib/python2.7/site-packages/redis/connection.py", line 569, in read_response
response = self._parser.read_response()
File "/home/user/.virtualenvs/Django/local/lib/python2.7/site-packages/redis/connection.py", line 224, in read_response
response = self._buffer.readline()
File "/home/user/.virtualenvs/Django/local/lib/python2.7/site-packages/redis/connection.py", line 162, in readline
self._read_from_socket()
File "/home/user/.virtualenvs/Django/local/lib/python2.7/site-packages/redis/connection.py", line 120, in _read_from_socket
data = self._sock.recv(socket_read_size)
File "/home/user/.virtualenvs/Django/local/lib/python2.7/site-packages/gevent/_socket2.py", line 253, in recv
self._wait(self._read_event)
File "/home/user/.virtualenvs/Django/local/lib/python2.7/site-packages/gevent/_socket2.py", line 152, in _wait
self.hub.wait(watcher)
File "/home/user/.virtualenvs/Django/local/lib/python2.7/site-packages/gevent/hub.py", line 559, in wait
result = waiter.get()
File "/home/user/.virtualenvs/Django/local/lib/python2.7/site-packages/gevent/hub.py", line 800, in get
return self.hub.switch()
File "/home/user/.virtualenvs/Django/local/lib/python2.7/site-packages/gevent/hub.py", line 538, in switch
return greenlet.switch(self)
LoopExit: ('This operation would block forever', <Hub at 0x7f3b65bb0370 epoll pending=0 ref=0 fileno=27>)
Of the five times the function is executed 3-4 times, or can execute all 5 times.
UPD (add code). My code something like that:
import json
from django.core.serializers.json import DjangoJSONEncoder
from .models import users, reports
from .helpers import FILTERS
KEYS = ['query_1', 'query_2', 'query_3', 'query_4', 'query_5']
def initial_data(request):
context = {}
user_names = users.objects.filter(**FILTERS).values_list('user_name', 'user_last_name', 'user_email')
user_names = {email: {' '.join((name, last_name)) for name, last_name, email in user_names}}
user_id = str(request.user.id)
try:
cache = get_cache('default')
cache.set(user_id, json.dumps(user_names, cls=DjangoJSONEncoder))
except:
context['errors'] = ["Can't get access to the Redis"]
else:
context['errors'] = []
return HttpResponse(json.dumps(context, cls=DjangoJSONEncoder), content_type="application/json")
def data(request):
context = {}
key = request.GET['key']
user_id = str(request.user.id)
cache = get_cache('default')
user_names = json.loads(cache.get(user_id))
if key == 'query_1':
emails = list(user_names.keys())[0:9]
if key == 'query_2':
emails = list(user_names.keys())[10:19]
if key == 'query_3':
emails = list(user_names.keys())[20:29]
if key == 'query_4':
emails = list(user_names.keys())[30:39]
if key == 'query_5':
emails = list(user_names.keys())[40:49]
result = reports.objects.filter(user_email__in=emails).values_list('date', 'text', 'user_email')
for date, text, email in result:
context[email] = [user_names[email], date, text]
return HttpResponse(json.dumps(context, cls=DjangoJSONEncoder), content_type="application/json")
In function initial_data I collect users information from database, that is necessary to filter reports and store it in Redis.
FE knows all KEYS ('query_1', 'query_2', 'query_3', 'query_4', 'query_5') and asynchronously sent request with one key at a time to the function data.
