I actually have custom error 500 page. This means, that when Django throws 
error, custom page should be shown.
But it is not the case. Standard white-background apache page is shown.
So, I think that problem is not in Django exception. Otherwise Django would 
show custom page, which is not the case.
In logs I saw only that server was restarted.
Can I somehow tune logging, so that real error is written?

On Sunday, February 15, 2015 at 2:44:50 AM UTC+2, Graham Dumpleton wrote:
>
>
> On 15/02/2015, at 10:53 AM, Paul Royik <[email protected] <javascript:>> 
> wrote: 
>
> > I already tried this approach. 
> > 
> > It seems good. 
> > But when I tested it on server, by simultaneously executing page on two 
> different computers, it gave me 500 error. 
> > 
> > How this can be explained? Again something with apache? Logs didn't show 
> anything. But I noticed again serious memory usage. And this happens only 
> when I use code for limiting time. 
>
>
> Some tips for you about ensuring you get the best help. 
>
> Stop discarding the message content for the message you are replying to. 
> It can be frustrating to have to keep going back to old messages to see 
> what was said originally and what you may be following up to, especially 
> when on a phone. When asking questions on mailing list, let the person you 
> are asking questions of decide what can be discarded from the message chain 
> as they will know better what should be kept in the message to provide easy 
> access to important information for context. 
>
> When you reply to say you are have a new error, provide the actual code 
> you were using exactly at the time you had the error. Saves the person who 
> is helping you having to go back and ask for it if it is unclear what code 
> you were using. 
>
> Your messages here and on StackOverflow show that you play around with the 
> example code I am giving you and I have reduced confidence you were running 
> with the code I suggested at the time of the problem you are now relating 
> to. 
>
> If you are getting 500 errors and nothing is being logged, it is because 
> Django is capturing the exception and converting it to a generic 500 error 
> response page. Configure Django to send you emails with the details of the 
> exceptions. If you are on a local system, then set DEBUG=True in the Django 
> settings so the details of the error are shown in response that goes back 
> to the browser. 
>
> As to the code, I did test it this time, including under mod_wsgi with 20 
> request threads and hitting it with concurrent and successive requests with 
> a benchmarking tool. I saw no issues and it appeared to behave as I would 
> expect. 
>
> So in a test2.py file I had: 
>
> import time 
> import functools 
> import threading 
>
> def time_limit(seconds): 
>     def decorator(func): 
>         func.info = threading.local() 
>         def check_timeout(): 
>             if time.time() > func.info.end_time: 
>                 raise RuntimeError('timeout') 
>
>         func.check_timeout = check_timeout 
>
>         @functools.wraps(func) 
>         def wrapper(*args, **kwargs): 
>             print 'hasattr counter', hasattr(func.info, 'counter') 
>             if not hasattr(func.info, 'counter'): 
>                 print 'init counter to 0' 
>                 func.info.counter = 0 
>             if func.info.counter == 0: 
>                 func.info.end_time = time.time() + seconds 
>             print 'counter', func.info.counter 
>             func.info.counter += 1 
>             try: 
>                 return func(*args, **kwargs) 
>             finally: 
>                 func.info.counter -= 1 
>
>         return wrapper 
>
>     return decorator 
>
> @time_limit(5) 
> def algorithm(limit, nest=0): 
>     algorithm.check_timeout() 
>     print 'sleep' 
>     time.sleep(1.0) 
>     if nest == limit: 
>         print 'return' 
>         return 
>     algorithm(limit, nest+1) 
>
> In serial2.py I had a straight serialised test: 
>
> from test2 import algorithm 
>
> try: 
>     algorithm(3) 
> except RuntimeError: 
>     print 'timeout' 
>
> try: 
>     algorithm(10) 
> except RuntimeError: 
>     print 'timeout' 
>
> try: 
>     algorithm(10) 
> except RuntimeError: 
>     print 'timeout' 
>
> And then in hello2.wsgi I had it used by a WSGI application. 
>
> from test2 import algorithm 
>
> def application(environ, start_response): 
>     status = '200 OK' 
>     output = b'Hello World!' 
>
>     algorithm(1) 
>
>     response_headers = [('Content-type', 'text/plain'), 
>                         ('Content-Length', str(len(output)))] 
>     start_response(status, response_headers) 
>
>     return [output] 
>
> In the latter case I ran mod_wsgi-express against it as: 
>
> mod_wsgi-express start-server hello2.wsgi --port 8002 --threads=20 
>
> and then hit it with ab as: 
>
> ab -n 100 -c 15 http://localhost:8002/ 
>
> In this case it wasn't designed to timeout anything, but that should not 
> be a concern as the counter initialisation is still being tested. 
>
> Do note that if you did cut and paste that last code, I did change the 
> exception type. 
>
> Anyway, the best thing to do is setup Django so that it provides the 
> details of the exception it captured but then effectively discarded because 
> it converted it to a 500 page. 
>
> Graham 
>
>
>
>
>
>

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