uwsgi interview questions
Top uwsgi frequently asked interview questions
Ubuntu 12.04, nginx 1.2.0, uwsgi 1.0.3.
I start uwsgi with the following command:
uwsgi -s 127.0.0.1:9010 -M -t 30 -A 4 -p 4 -d /var/log/uwsgi.log
On each request nginx replies with 502 and uwsgi writes to log the following line:
-- unavailable modifier requested: 0 --
Source: (StackOverflow)
I can see that if I start uwsgi like this:
sudo /usr/local/bin/uwsgi --emperor /etc/uwsgi/vassals --uid www --gid www
it creates one emperor copy. But if I start it with --master additionally (as recommended here), it creates two emperor copies. Does it make sense to use --master with --emperor? I would say no, but if I run it without that option I get this warning:
*** WARNING: you are running uWSGI without its master process manager ***
Source: (StackOverflow)
I am running a django app with nginx & uwsgi. Here's how i run uwsgi:
sudo uwsgi -b 25000 --chdir=/www/python/apps/pyapp --module=wsgi:application --env DJANGO_SETTINGS_MODULE=settings --socket=/tmp/pyapp.socket --cheaper=8 --processes=16 --harakiri=10 --max-requests=5000 --vacuum --master --pidfile=/tmp/pyapp-master.pid --uid=220 --gid=499
& nginx configurations:
server {
listen 80;
server_name test.com
root /www/python/apps/pyapp/;
access_log /var/log/nginx/test.com.access.log;
error_log /var/log/nginx/test.com.error.log;
# https://docs.djangoproject.com/en/dev/howto/static-files/#serving-static-files-in-production
location /static/ {
alias /www/python/apps/pyapp/static/;
expires 30d;
}
location /media/ {
alias /www/python/apps/pyapp/media/;
expires 30d;
}
location / {
uwsgi_pass unix:///tmp/pyapp.socket;
include uwsgi_params;
proxy_read_timeout 120;
}
# what to serve if upstream is not available or crashes
#error_page 500 502 503 504 /media/50x.html;
}
Here comes the problem. When doing "ab" (ApacheBenchmark) on the server i get the following results:
nginx version: nginx version: nginx/1.2.6
uwsgi version:1.4.5
Server Software: nginx/1.0.15
Server Hostname: pycms.com
Server Port: 80
Document Path: /api/nodes/mostviewed/8/?format=json
Document Length: 8696 bytes
Concurrency Level: 100
Time taken for tests: 41.232 seconds
Complete requests: 1000
Failed requests: 0
Write errors: 0
Total transferred: 8866000 bytes
HTML transferred: 8696000 bytes
Requests per second: 24.25 [#/sec] (mean)
Time per request: 4123.216 [ms] (mean)
Time per request: 41.232 [ms] (mean, across all concurrent requests)
Transfer rate: 209.99 [Kbytes/sec] received
While running on 500 concurrency level
oncurrency Level: 500
Time taken for tests: 2.175 seconds
Complete requests: 1000
Failed requests: 50
(Connect: 0, Receive: 0, Length: 50, Exceptions: 0)
Write errors: 0
Non-2xx responses: 950
Total transferred: 629200 bytes
HTML transferred: 476300 bytes
Requests per second: 459.81 [#/sec] (mean)
Time per request: 1087.416 [ms] (mean)
Time per request: 2.175 [ms] (mean, across all concurrent requests)
Transfer rate: 282.53 [Kbytes/sec] received
As you can see... all requests on the server fail with either timeout errors or "Client prematurely disconnected" or:
writev(): Broken pipe [proto/uwsgi.c line 124] during GET /api/nodes/mostviewed/9/?format=json
Here's a little bit more about my application:
Basically, it's a collection of models that reflect MySQL tables which contain all the content. At the frontend, i have django-rest-framework which serves json content to the clients.
I've installed django-profiling & django debug toolbar to see whats going on. On django-profiling here's what i get when running a single request:
Instance wide RAM usage
Partition of a set of 147315 objects. Total size = 20779408 bytes.
Index Count % Size % Cumulative % Kind (class / dict of class)
0 63960 43 5726288 28 5726288 28 str
1 36887 25 3131112 15 8857400 43 tuple
2 2495 2 1500392 7 10357792 50 dict (no owner)
3 615 0 1397160 7 11754952 57 dict of module
4 1371 1 1236432 6 12991384 63 type
5 9974 7 1196880 6 14188264 68 function
6 8974 6 1076880 5 15265144 73 types.CodeType
7 1371 1 1014408 5 16279552 78 dict of type
8 2684 2 340640 2 16620192 80 list
9 382 0 328912 2 16949104 82 dict of class
<607 more rows. Type e.g. '_.more' to view.>
CPU Time for this request
11068 function calls (10158 primitive calls) in 0.064 CPU seconds
Ordered by: cumulative time
ncalls tottime percall cumtime percall filename:lineno(function)
1 0.000 0.000 0.064 0.064 /usr/lib/python2.6/site-packages/django/views/generic/base.py:44(view)
1 0.000 0.000 0.064 0.064 /usr/lib/python2.6/site-packages/django/views/decorators/csrf.py:76(wrapped_view)
1 0.000 0.000 0.064 0.064 /usr/lib/python2.6/site-packages/rest_framework/views.py:359(dispatch)
1 0.000 0.000 0.064 0.064 /usr/lib/python2.6/site-packages/rest_framework/generics.py:144(get)
1 0.000 0.000 0.064 0.064 /usr/lib/python2.6/site-packages/rest_framework/mixins.py:46(list)
1 0.000 0.000 0.038 0.038 /usr/lib/python2.6/site-packages/rest_framework/serializers.py:348(data)
21/1 0.000 0.000 0.038 0.038 /usr/lib/python2.6/site-packages/rest_framework/serializers.py:273(to_native)
21/1 0.000 0.000 0.038 0.038 /usr/lib/python2.6/site-packages/rest_framework/serializers.py:190(convert_object)
11/1 0.000 0.000 0.036 0.036 /usr/lib/python2.6/site-packages/rest_framework/serializers.py:303(field_to_native)
13/11 0.000 0.000 0.033 0.003 /usr/lib/python2.6/site-packages/django/db/models/query.py:92(__iter__)
3/1 0.000 0.000 0.033 0.033 /usr/lib/python2.6/site-packages/django/db/models/query.py:77(__len__)
4 0.000 0.000 0.030 0.008 /usr/lib/python2.6/site-packages/django/db/models/sql/compiler.py:794(execute_sql)
1 0.000 0.000 0.021 0.021 /usr/lib/python2.6/site-packages/django/views/generic/list.py:33(paginate_queryset)
1 0.000 0.000 0.021 0.021 /usr/lib/python2.6/site-packages/django/core/paginator.py:35(page)
1 0.000 0.000 0.020 0.020 /usr/lib/python2.6/site-packages/django/core/paginator.py:20(validate_number)
3 0.000 0.000 0.020 0.007 /usr/lib/python2.6/site-packages/django/core/paginator.py:57(_get_num_pages)
4 0.000 0.000 0.020 0.005 /usr/lib/python2.6/site-packages/django/core/paginator.py:44(_get_count)
1 0.000 0.000 0.020 0.020 /usr/lib/python2.6/site-packages/django/db/models/query.py:340(count)
1 0.000 0.000 0.020 0.020 /usr/lib/python2.6/site-packages/django/db/models/sql/query.py:394(get_count)
1 0.000 0.000 0.020 0.020 /usr/lib/python2.6/site-packages/django/db/models/query.py:568(_prefetch_related_objects)
1 0.000 0.000 0.020 0.020 /usr/lib/python2.6/site-packages/django/db/models/query.py:1596(prefetch_related_objects)
4 0.000 0.000 0.020 0.005 /usr/lib/python2.6/site-packages/django/db/backends/util.py:36(execute)
1 0.000 0.000 0.020 0.020 /usr/lib/python2.6/site-packages/django/db/models/sql/query.py:340(get_aggregation)
5 0.000 0.000 0.020 0.004 /usr/lib64/python2.6/site-packages/MySQLdb/cursors.py:136(execute)
2 0.000 0.000 0.020 0.010 /usr/lib/python2.6/site-packages/django/db/models/query.py:1748(prefetch_one_level)
4 0.000 0.000 0.020 0.005 /usr/lib/python2.6/site-packages/django/db/backends/mysql/base.py:112(execute)
5 0.000 0.000 0.019 0.004 /usr/lib64/python2.6/site-packages/MySQLdb/cursors.py:316(_query)
60 0.000 0.000 0.018 0.000 /usr/lib/python2.6/site-packages/django/db/models/query.py:231(iterator)
5 0.012 0.002 0.015 0.003 /usr/lib64/python2.6/site-packages/MySQLdb/cursors.py:278(_do_query)
60 0.000 0.000 0.013 0.000 /usr/lib/python2.6/site-packages/django/db/models/sql/compiler.py:751(results_iter)
30 0.000 0.000 0.010 0.000 /usr/lib/python2.6/site-packages/django/db/models/manager.py:115(all)
50 0.000 0.000 0.009 0.000 /usr/lib/python2.6/site-packages/django/db/models/query.py:870(_clone)
51 0.001 0.000 0.009 0.000 /usr/lib/python2.6/site-packages/django/db/models/sql/query.py:235(clone)
4 0.000 0.000 0.009 0.002 /usr/lib/python2.6/site-packages/django/db/backends/__init__.py:302(cursor)
4 0.000 0.000 0.008 0.002 /usr/lib/python2.6/site-packages/django/db/backends/mysql/base.py:361(_cursor)
1 0.000 0.000 0.008 0.008 /usr/lib64/python2.6/site-packages/MySQLdb/__init__.py:78(Connect)
910/208 0.003 0.000 0.008 0.000 /usr/lib64/python2.6/copy.py:144(deepcopy)
22 0.000 0.000 0.007 0.000 /usr/lib/python2.6/site-packages/django/db/models/query.py:619(filter)
22 0.000 0.000 0.007 0.000 /usr/lib/python2.6/site-packages/django/db/models/query.py:633(_filter_or_exclude)
20 0.000 0.000 0.005 0.000 /usr/lib/python2.6/site-packages/django/db/models/fields/related.py:560(get_query_set)
1 0.000 0.000 0.005 0.005 /usr/lib64/python2.6/site-packages/MySQLdb/connections.py:8()
..etc
However, django-debug-toolbar shows the following:
Resource Usage
Resource Value
User CPU time 149.977 msec
System CPU time 119.982 msec
Total CPU time 269.959 msec
Elapsed time 326.291 msec
Context switches 11 voluntary, 40 involuntary
and 5 queries in 27.1 ms
The problem is that "top" shows the load average rising quickly and apache benchmark which i ran both on the local server and from a remote machine within the network shows that i am not serving many requests / second.
What is the problem? this is as far as i could reach when profiling the code so it would be appreciated if someone can point of what i am doing here.
Edit (23/02/2013): Adding more details based on Andrew Alcock's answer:
The points that require my attention / answer are
(3)(3) I've executed "show global variables" on MySQL and found out that MySQL configurations had 151 for max_connections setting which is more than enough to serve the workers i am starting for uwsgi.
(3)(4)(2) The single request i am profiling is the heaviest one. It executes 4 queries according to django-debug-toolbar. What happens is that all queries run in:
3.71, 2.83, 0.88, 4.84 ms respectively.
(4) Here you're referring to memory paging? if so, how could i tell?
(5) On 16 workers, 100 concurrency rate, 1000 requests the load average goes up to ~ 12
I ran the tests on different number of workers (concurrency level is 100):
- 1 worker, load average ~ 1.85, 19 reqs / second, Time per request: 5229.520, 0 non-2xx
- 2 worker, load average ~ 1.5, 19 reqs / second, Time per request: 516.520, 0 non-2xx
- 4 worker, load average ~ 3, 16 reqs / second, Time per request: 5929.921, 0 non-2xx
- 8 worker, load average ~ 5, 18 reqs / second, Time per request: 5301.458, 0 non-2xx
- 16 worker, load average ~ 19, 15 reqs / second, Time per request: 6384.720, 0 non-2xx
AS you can see, the more workers we have, the more load we have on the system. I can see in uwsgi's daemon log that the response time in milliseconds increases when i increase the number of workers.
On 16 workers, running 500 concurrency level requests uwsgi starts loggin the errors:
writev(): Broken pipe [proto/uwsgi.c line 124]
Load goes up to ~ 10 as well. and the tests don't take much time because non-2xx responses are 923 out of 1000 which is why the response here is quite fast as it's almost empty. Which is also a reply to your point #4 in the summary.
Assuming that what i am facing here is an OS latency based on I/O and networking, what is the recommended action to scale this up? new hardware? bigger server?
Thanks
Source: (StackOverflow)
Could anyone please explain pros/cons when using WSGI VS uWSGI with Nginx.
Currently i am building up a production server for the Django website which i have prepared but unable to decide whether should i go with WSGI or uWSGI. Could you please explain in detail what differentiates each configuration? Which configuration should scale the best?
Thanks in advance
Source: (StackOverflow)
I am getting a lot of 499 nginx error codes. I see that this is a client side issue. It is not a problem with Nginx or my uWSGI stack. I note the correlation in uWSGI logs when a get a 499.
address space usage: 383692800 bytes/365MB} {rss usage: 167038976
bytes/159MB} [pid: 16614|app: 0|req: 74184/222373] 74.125.191.16 ()
{36 vars in 481 bytes} [Fri Oct 19 10:07:07 2012] POST /bidder/ =>
generated 0 bytes in 8 msecs (HTTP/1.1 200) 1 headers in 59 bytes (1
switches on core 1760)
SIGPIPE: writing to a closed pipe/socket/fd (probably the client
disconnected) on request /bidder/ (ip 74.125.xxx.xxx) !!!
Fri Oct 19 10:07:07 2012 - write(): Broken pipe [proto/uwsgi.c line
143] during POST /bidder/ (74.125.xxx.xxx)
IOError: write error
I am looking for a more indepth explanation and hoping it is nothing wrong with my nginx config for uwsgi. I am taking it on face value...its not a me problem..its a client issue.
Thanks
Source: (StackOverflow)
when running uwsgi i get the following message:
!!! no internal routing support, rebuild with pcre support !!!
I already have installed pcre (I think) with the following command:
Sudo apt-get install libpcre3 libpcre3-dev
My question is: Why am I still getting this message even after I have installed the pcre package and if I need to reinstall uwsgi and activate pcre how do I do it?
Also, does internal routing matter? I assume it does or else the makers of uwsgi wouldn't have made the message come up. I am running Ubuntu 12.04 LTS.
Thanks for the help!
Source: (StackOverflow)
I'm not looking to turn on the dangerous debugging console, but my application is getting a 500 error and doesn't seem to be writing any output for me to investigate more deeply.
I saw this exchange on the mailing list, which led me to this page on logging errors.
However, I still find this very confusing and have a couple of questions:
(1) In which file should the stuff below go?
ADMINS = ['yourname@example.com']
if not app.debug:
import logging
from logging.handlers import SMTPHandler
mail_handler = SMTPHandler('127.0.0.1',
'server-error@example.com',
ADMINS, 'YourApplication Failed')
mail_handler.setLevel(logging.ERROR)
app.logger.addHandler(mail_handler)
...assuming the "getting bigger" file pattern for larger applications? __init__.py? config.py? run.py?
(2) I am overwhelmed by options there, and can't tell which I should use. Which loggers should I turn on, with what settings, to replicate the local python server debug I get to stdout when I run run.py? I find that default, local output stream very useful, more so than the interactive debugger in the page. Does anyone have a pattern they could share on setting up something replicating this with an nginx deployment, outputting to a log?
(3) Is there anything I need to change, not at the flask level, but in nginx, say in my /etc/nginx/sites-available/appname file, to enable logging?
UPDATE
Specifically, I'm looking for information like I get when python runs locally as to why, say, a package isn't working, or where my syntax error might be, or what variable doesn't exist:
$ python run.py
Traceback (most recent call last):
File "run.py", line 1, in <module>
from myappname import app
File "/home/me/myappname/myappname/__init__.py", line 27, in <module>
file_handler.setLevel(logging.debug)
File "/usr/lib/python2.7/logging/__init__.py", line 710, in setLevel
self.level = _checkLevel(level)
File "/usr/lib/python2.7/logging/__init__.py", line 190, in _checkLevel
raise TypeError("Level not an integer or a valid string: %r" % level)
When I run flask on a server, I never see this. I just get a uWSGI error in the browser, and have no idea which code was problematic. I would just like something like the above to be written to a file.
I notice also that setting the following logging didn't really write much to file, even when I turn the log way up to the DEBUG level:
from logging import FileHandler
file_handler = FileHandler('mylog.log')
file_handler.setLevel(logging.DEBUG)
app.logger.addHandler(file_handler)
mylog.log is blank, even when my application errors out.
I'll also add that I've tried to set debug = True in the following ways, in __init__.py:
app = Flask(__name__)
app.debug = True
app.config['DEBUG'] = True
from werkzeug.debug import DebuggedApplication
app.wsgi_app = DebuggedApplication(app.wsgi_app, True)
app.config.from_object('config')
app.config.update(DEBUG=True)
app.config['DEBUG'] = True
if __name__ == '__main__':
app.run(debug=True)
While in my config.py file, I have...
debug = True
Debug = True
DEBUG = True
Yet, no debugging happens, and without logging or debugging, this is rather hard to track down. Errors simply terminate the application with the un-useful browser message:
uWSGI Error
Python application not found
Source: (StackOverflow)
I'm running uwsgi in emperor mode
uwsgi --emperor /path/to/vassals/ --buffer-size=32768
and getting this error
invalid request block size: 21327 (max 4096)...skip
What to do?? I also tried -b 32768
Source: (StackOverflow)
I have a error message on django 1.4:
dictionary update sequence element #0 has length 1; 2 is required
[EDIT]
It happened when I tried when using template tag like: `{% for v in values %}:
dictionary update sequence element #0 has length 1; 2 is required
Request Method: GET
Request URL: ...
Django Version: 1.4.5
Exception Type: ValueError
Exception Value:
dictionary update sequence element #0 has length 1; 2 is required
Exception Location: /usr/local/lib/python2.7/dist-packages/djorm_hstore/fields.py in __init__, line 21
Python Executable: /usr/bin/uwsgi-core
Python Version: 2.7.3
Python Path:
['/var/www/',
'.',
'',
'/usr/lib/python2.7',
'/usr/lib/python2.7/plat-linux2',
'/usr/lib/python2.7/lib-tk',
'/usr/lib/python2.7/lib-old',
'/usr/lib/python2.7/lib-dynload',
'/usr/local/lib/python2.7/dist-packages',
'/usr/lib/python2.7/dist-packages',
'/usr/lib/python2.7/dist-packages/PIL',
'/usr/lib/pymodules/python2.7']
Server time: sam, 13 Jul 2013 16:15:45 +0200
Error during template rendering
In template /var/www/templates/app/index.html, error at line 172
dictionary update sequence element #0 has length 1; 2 is required
172 {% for product in products %}
Traceback Switch to copy-and-paste view
/usr/lib/python2.7/dist-packages/django/core/handlers/base.py in get_response
response = callback(request, *callback_args, **callback_kwargs)
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/contrib/auth/decorators.py in _wrapped_view
return view_func(request, *args, **kwargs)
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/views/decorators/http.py in inner
return func(request, *args, **kwargs)
...
▶ Local vars
./app/views.py in index
context_instance=RequestContext(request))
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/shortcuts/__init__.py in render_to_response
return HttpResponse(loader.render_to_string(*args, **kwargs), **httpresponse_kwargs)
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/loader.py in render_to_string
return t.render(context_instance)
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/base.py in render
return self._render(context)
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/base.py in _render
return self.nodelist.render(context)
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/base.py in render
bit = self.render_node(node, context)
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/debug.py in render_node
return node.render(context)
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/loader_tags.py in render
return compiled_parent._render(context)
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/base.py in _render
return self.nodelist.render(context)
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/base.py in render
bit = self.render_node(node, context)
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/debug.py in render_node
return node.render(context)
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/loader_tags.py in render
result = block.nodelist.render(context)
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/base.py in render
bit = self.render_node(node, context)
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/debug.py in render_node
return node.render(context)
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/template/defaulttags.py in render
len_values = len(values)
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/core/paginator.py in __len__
return len(self.object_list)
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/db/models/query.py in __len__
self._result_cache = list(self.iterator())
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/db/models/query.py in iterator
obj = model(*row[index_start:aggregate_start])
...
▶ Local vars
/usr/lib/python2.7/dist-packages/django/db/models/base.py in __init__
setattr(self, field.attname, val)
...
▶ Local vars
/usr/local/lib/python2.7/dist-packages/djorm_hstore/fields.py in __set__
value = self.field._attribute_class(value, self.field, obj)
...
▶ Local vars
/usr/local/lib/python2.7/dist-packages/djorm_hstore/fields.py in __init__
super(HStoreDictionary, self).__init__(value, **params)
...
▶ Local vars
It happens too when I try to access on a hstore queryset:
[edit]
Traceback (most recent call last):
File "manage.py", line 14, in <module>
execute_manager(settings)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 459, in execute_manager
utility.execute()
File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 382, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 196, in run_from_argv
self.execute(*args, **options.__dict__)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 232, in execute
output = self.handle(*args, **options)
File "/home/name/workspace/project/app/data/commands/my_command.py", line 60, in handle
item_id = tmp[0].id,
File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 207, in __getitem__
return list(qs)[0]
File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 87, in __len__
self._result_cache.extend(self._iter)
File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 301, in iterator
obj = model(*row[index_start:aggregate_start])
File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 300, in __init__
setattr(self, field.attname, val)
File "/usr/local/lib/python2.7/dist-packages/djorm_hstore/fields.py", line 38, in __set__
value = self.field._attribute_class(value, self.field, obj)
File "/usr/local/lib/python2.7/dist-packages/djorm_hstore/fields.py", line 21, in __init__
super(HStoreDictionary, self).__init__(value, **params)
ValueError: dictionary update sequence element #0 has length 1; 2 is required
the code is:
tmp = Item.objects.where(HE("kv").contains({'key':value}))
if tmp.count() > 0:
item_id = tmp[0].id,
I just try to access to the value I don't understand the "update sequence" message. When I use a cursor instead of hstore queryset the function works. The error come on template rendering too , I just restarted uwsgi and everything works well, but error come back later
[edit]
Has someone an idea?
Source: (StackOverflow)
For my current flask deployment, I had to set up a uwsgi server.
This is how I have created the uwsgi daemon:
sudo vim /etc/init/uwsgi.conf
# file: /etc/init/uwsgi.conf
description "uWSGI server"
start on runlevel [2345]
stop on runlevel [!2345]
respawn
exec /myproject/myproject-env/bin/uwsgi --uid www-data --gid www-data --home /myproject/myproject-env/site/F11/Engineering/ --socket /tmp/uwsgi.sock --chmod-socket --module F11 --callable app --pythonpath /myproject/myproject-env/site/F11/Engineering/ -H /myproject/myproject-env
However after running this successfully: sudo start uwsgi
uwsgi start/running, process 1286
And trying to access the application via browser:
I get a 502 Bad Gateway
and an error entry in nginx error.log:
2013/06/13 23:47:28 [error] 743#0: *296 upstream prematurely closed
connection while reading response header from upstream, client:
xx.161.xx.228, server: myproject.com, request: "GET /show_records/2013/6 HTTP/1.1", upstream:
"uwsgi://unix:///tmp/uwsgi.sock:", host: "myproject.com"
But the sock file has the permission it needs:
srw-rw-rw- 1 www-data www-data 0 Jun 13 23:46 /tmp/uwsgi.sock
If I run the exec command from above in the command line as a process, it works perfectly fine. Why is the daemon not working correctly please?
btw Nginx is running as
vim /etc/nginx/nginx.conf
user www-data;
and vim /etc/nginx/sites-available/default
location / {
uwsgi_pass unix:///tmp/uwsgi.sock;
include uwsgi_params;
}
and it is started as sudo service nginx start
I am running this on Ubuntu 12.04 LTS.
I hope I have provided all the necessary data, hope someone can guide me into the right direction. Thanks.
Source: (StackOverflow)
My flask app is doing a 301 redirect for one of the urls.
The traceback in New Relic is:
Traceback (most recent call last):
File "/var/www/app/env/local/lib/python2.7/site-packages/flask/app.py", line 1358, in full_dispatch_request
rv = self.dispatch_request()
File "/var/www/app/env/local/lib/python2.7/site-packages/flask/app.py", line 1336, in dispatch_request
self.raise_routing_exception(req)
File "/var/www/app/env/local/lib/python2.7/site-packages/flask/app.py", line 1319, in raise_routing_exception
raise request.routing_exception
RequestRedirect: 301: Moved Permanently
It doesn't look like it is even hitting my code or rather the traceback isn't showing any of my files in it. At one point I did have Nginx redirect all non SSL request to HTTPS but had to disable that as Varnish was not able to make the request to port 443 with out an error... probably some configuration that I did or didn't make.
It doesn't always return a 301 though, I can request the URL and get it without any trouble. But someone out in the world requesting the URL is getting a 301 response.
It is a GET request with some custom headers to link it to the account.
At no point in my code is there a 301 redirect.
Source: (StackOverflow)
I get the below error when I try and start Flask using uWSGI.
Here is how I start:
> # cd ..
> root@localhost:# uwsgi --socket 127.0.0.1:6000 --file /path/to/folder/run.py --callable app - -processes 2
Here is my directory structure:
-/path/to/folder/run.py
-|app
-|__init__.py
-|views.py
-|templates
-|static
Contents of /path/to/folder/run.py
if __name__ == '__main__':
from app import app
#app.run(debug = True)
app.run()
Contents of /path/to/folder/app/__init__.py
import os
from flask import Flask
from flask.ext.sqlalchemy import SQLAlchemy
from flask.ext.login import LoginManager
#from flaskext.babel import Babel
from config import basedir
app = Flask(__name__)
app.config.from_object('config')
#app.config.from_pyfile('babel.cfg')
db = SQLAlchemy(app)
login_manager = LoginManager()
login_manager.setup_app(app)
login_manager.login_view = 'login'
login_manager.login_message = u"Please log in to access this page."
from app import views
*** Operational MODE: preforking ***
unable to find "application" callable in file /path/to/folder/run.py
unable to load app 0 (mountpoint='') (callable not found or import error)
*** no app loaded. going in full dynamic mode ***
*** uWSGI is running in multiple interpreter mode ***
spawned uWSGI worker 1 (pid: 26972, cores: 1)
spawned uWSGI worker 2 (pid: 26973, cores: 1)
Source: (StackOverflow)
Is it possible to debug a uwsgi application using an ide like PyCharm? I can debug flask based apps fine by running them directly from pycharm but cannot even run a uwsgi app from within pycharm.
Do I have to use remote debugging? Is it possible to start a uwsgi app from within pycharm using run?
Source: (StackOverflow)
web2py is an awesome python framework which has great documentation including several deployment recipes. Yet what I miss there is the recipe for deploying using nginx (preferably with uwsgi). There are some incomplete notes around the web (like here), but I couldn't find any complete, stand-alone guide. So, I appreciate your help.
Source: (StackOverflow)
Environment is Nginx + uwsgi.
Getting a 502 bad gateway error from Nginx on certain GET requests. Seems to be related to the length of the URL. In our particular case, it was a long list of GET parameters. Shorten the GET parameters and no 502 error.
From the nginx/error.log
[error] 22113#0: *1 recv() failed (104: Connection reset by peer) while reading response header from upstream, client: 192.168.1.100, server: server.domain.com, request: "GET <long_url_here>"
No information in the uwsgi error log.
Source: (StackOverflow)