why would you use a library made to use gevent in an environment that
doesn't support it ?
if you need to use gevent-coroutines-etc-etc-etc you need to have the
COMPLETE env supporting it, not just a piece.
On Thursday, April 21, 2016 at 7:49:25 AM UTC+2, Kiran Subbaraman wrote:
>
> Narrowed down the issue. Basically, the grequests modules that I was using
> seems to be the cause of the "LoopExit: This operation would block
> forever"
>
> Create an application: *redis_event*
>
> *controller: default.py*
> import cache_mod
>
> def index():
> return dict(message=cache_mod.get_value())
>
> *module: cache_mod.py*
> import redis
> import grequests
>
> redis_cache = redis.StrictRedis(host='localhost', port=6379, db=0)
>
> def get_value(key='SOME_KEY'):
> return redis_cache.get(key)
>
> view: index.html
> <h2>{{=message}}</h2>
>
> Once deployed on the server, access this url:
> http://127.0.0.1:8000/redis_event/default/index
> Reload the page successively - repeatedly F5 after page load - and you
> will notice the error on the page.
>
> Am moving away from grequests, and settling for just requests.
>
>
>
> On Thursday, April 21, 2016 at 9:44:42 AM UTC+5:30, Kiran Subbaraman wrote:
>>
>> Thanks for the recommendation - IIS with web2py is a recommended
>> deployment on Windows.
>>
>> The gevent-mix-up-with-rocket, was based on the stack trace I pasted
>> below. And like I mentioned, this connection was made without any evidence
>> ... so yeah, I was writing this before I gave it too much thought or
>> investigation.
>> In any case, I'll do some more investigation and try to track down this
>> issue.
>>
>> ________________________________________
>> Kiran Subbaramanhttp://subbaraman.wordpress.com/about/
>>
>> On Thu, 21-04-2016 3:42 AM, Niphlod wrote:
>>
>> forget about uwsgi on windows. never really landed as production-ready.
>> fortunately iis can run python without any hiccup and it's the current
>> recommended way to deploy web2py in production on windows.
>>
>> that being said, I'm really eager to know how the hell you're getting
>> gevent mixed up with web2py's internal webserver, which is not at all
>> compatible with gevent.
>>
>> On Wednesday, April 20, 2016 at 7:21:09 PM UTC+2, Kiran Subbaraman wrote:
>>>
>>> Hello all,
>>> I use Windows 10 based laptop for my development. By default, web2py
>>> serves its content via the rocket server.
>>> My application makes use of the 'default' redis client () to connect to
>>> the local redis server.
>>> I started noticing a stacktrace, in the cmd prompt, from within which
>>> web2py has started:
>>> Created by Massimo Di Pierro, Copyright 2007-2016
>>> Version 2.14.3-stable+timestamp.2016.03.26.17.54.43
>>> Database drivers available: psycopg2, pymysql, imaplib, sqlite3, pg8000,
>>> pyodbc, mysqlconnector
>>> please visit:
>>> http://127.0.0.1:8000/
>>> starting browser...
>>> please visit:
>>> http://127.0.0.1:8000/
>>> starting browser...
>>> 2016-04-20 20:26:54,003 - Rocket.Errors.Port8000 - ERROR - Traceback (most
>>> recent call last):
>>> File "d:\code\git\web2py\gluon\rocket.py", line 587, in listen
>>> sock, addr = self.listener.accept()
>>> File "D:\programs\open\python27\lib\site-packages\gevent\socket.py",
>>> line 316, in accept
>>> self._wait(self._read_event)
>>> File "D:\programs\open\python27\lib\site-packages\gevent\socket.py",
>>> line 300, in _wait
>>> self.hub.wait(watcher)
>>> File "D:\programs\open\python27\lib\site-packages\gevent\hub.py",
>>> line 348, in wait
>>> result = waiter.get()
>>> File "D:\programs\open\python27\lib\site-packages\gevent\hub.py",
>>> line 575, in get
>>> return self.hub.switch()
>>> File "D:\programs\open\python27\lib\site-packages\gevent\hub.py",
>>> line 338, in switch
>>> return greenlet.switch(self)
>>> LoopExit: This operation would block forever
>>>
>>> The error in the error-ticket is:
>>> <class 'gevent.hub.LoopExit'> This operation would block forever
>>> Version
>>> web2py™ Version 2.14.3-stable+timestamp.2016.03.26.17.54.43
>>> Python Python 2.7.10: D:\programs\open\python27\python.exe (prefix:
>>> D:\programs\open\python27)
>>> Traceback
>>>
>>>
>>> Traceback (most recent call last):
>>> File "d:\code\git\web2py\gluon\restricted.py", line 227, in restricted
>>> exec ccode in environment
>>> File "d:/code/git/web2py/applications/myapp/controllers/myservice.py",
>>> line 99, in <module>
>>> File "d:\code\git\web2py\gluon\globals.py", line 417, in <lambda>
>>> self._caller = lambda f: f()
>>> File "d:\code\git\web2py\gluon\cache.py", line 661, in wrapped_f
>>> rtn = func()
>>> File "d:/code/git/web2py/applications/myapp/controllers/myservice.py",
>>> line 68, in data
>>> data = api.get_data(url)
>>> File "applications\myapp\modules\data\api.py", line 145, in get_data
>>> return _get_data_for(url) if url else None
>>> File "applications\myapp\modules\data\api.py", line 164, in
>>> _get_data_for
>>> force_reload=rebuild
>>> File "applications\myapp\modules\myapp_constants.py", line 460, in
>>> get_from_cache
>>> cache_value = redis_cache.get(key)
>>> File "D:\programs\open\python27\lib\site-packages\redis\client.py",
>>> line 880, in get
>>> return self.execute_command('GET', name)
>>> File "D:\programs\open\python27\lib\site-packages\redis\client.py",
>>> line 573, in execute_command
>>> return self.parse_response(connection, command_name, **options)
>>> File "D:\programs\open\python27\lib\site-packages\redis\client.py",
>>> line 585, in parse_response
>>> response = connection.read_response()
>>> File
>>> "D:\programs\open\python27\lib\site-packages\redis\connection.py", line
>>> 577, in read_response
>>> response = self._parser.read_response()
>>> File
>>> "D:\programs\open\python27\lib\site-packages\redis\connection.py", line
>>> 238, in read_response
>>> response = self._buffer.readline()
>>> File
>>> "D:\programs\open\python27\lib\site-packages\redis\connection.py", line
>>> 168, in readline
>>> self._read_from_socket()
>>> File
>>> "D:\programs\open\python27\lib\site-packages\redis\connection.py", line
>>> 126, in _read_from_socket
>>> data = self._sock.recv(socket_read_size)
>>> File "D:\programs\open\python27\lib\site-packages\gevent\socket.py",
>>> line 394, in recv
>>> self._wait(self._read_event)
>>> File "D:\programs\open\python27\lib\site-packages\gevent\socket.py",
>>> line 300, in _wait
>>> self.hub.wait(watcher)
>>> File "D:\programs\open\python27\lib\site-packages\gevent\hub.py", line
>>> 348, in wait
>>> result = waiter.get()
>>> File "D:\programs\open\python27\lib\site-packages\gevent\hub.py", line
>>> 575, in get
>>> return self.hub.switch()
>>> File "D:\programs\open\python27\lib\site-packages\gevent\hub.py", line
>>> 338, in switch
>>> return greenlet.switch(self)
>>> LoopExit: This operation would block forever
>>>
>>> I do not see this issue on my ubuntu linux deployment.
>>>
>>> I suspected, without any evidence, that it may have to do with
>>> process/threading between the rocket server to redis_client, and that it
>>> could do with the monkey_patching of socket in the gevent world. Again, I
>>> do not have any evidence, other than the stacktrace.
>>>
>>> The knee-jerk reaction was to see if using uwsgi or nginx on windows
>>> alleviates this issue. The nearest discussion thread, that I came across,
>>> that talks about setting up such an environment (web2py without rocket, but
>>> uwsgi / nginx) is this one:
>>> https://groups.google.com/forum/#!searchin/web2py/nginx$20windows/web2py/NdV0CVX8zZs/wWiRxogLz4sJ
>>>
>>> Any thoughts on what I could do or take a look at will help. Thanks.
>>>
>>> In the meantime, I also intend to
>>>
>>> - create a minimal app that is able to recreate this issue.
>>> - take a look at the web2py's redis-cache.
>>>
>>> --
>> Resources:
>> - http://web2py.com
>> - http://web2py.com/book (Documentation)
>> - http://github.com/web2py/web2py (Source code)
>> - https://code.google.com/p/web2py/issues/list (Report Issues)
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>>
>>
--
Resources:
- http://web2py.com
- http://web2py.com/book (Documentation)
- http://github.com/web2py/web2py (Source code)
- https://code.google.com/p/web2py/issues/list (Report Issues)
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