ResourceWarning unclosed <socket.socket>

[Phyks]

Hi,

When quitting a Bottle app using ^C and the built-in webserver, I get this message in the console:

/bottle.py:3119: ResourceWarning: unclosed <socket.socket fd=4, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('127.0.0.1', 8080)>

Then, it hangs, and I have to ^C a second times to exit.

It should not be a big deal, but I never saw it before. Is it due to some recent changes? Thanks!

[defnull]

Which Python an Bottle version?

[Phyks]

Python 3.5.1. Bottle 0.12.9 installed from pip.

[Phyks]

Let me know if I can be useful in any way :)

[tprk77]

Me too! Xubuntu 16.04 x86_64, virtualenv, Python 3.5.2, Bottle 0.12.9 from pip.

[katsar0v]

Same here still valid

[Lisias]

I confirm this is still a problem.

Python 3.4.2 (default, Oct 19 2014, 13:31:11)
[GCC 4.9.1] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import bottle
>>> bottle.__version__
'0.13-dev'
>>>

And later, after hitting CTRL-C to stop a program:

sys:1: ResourceWarning: unclosed <socket.socket fd=5, family=AddressFamily.AF_UNIX, type=2049, proto=0>
/home/srv/python/3.4/lib/python3.4/importlib/_bootstrap.py:2150: ImportWarning: sys.meta_path is empty
sys:1: ResourceWarning: unclosed <socket.socket fd=6, family=AddressFamily.AF_UNIX, type=2049, proto=0>

[ahxxm]

+1

python3.5.2 and 3.6.1rc1, bottle 0.12.13, paste 2.0.3

[defnull]

I still cannot reproduce this error. I do get the 'unclosed resource' warning, but the process does not hang.

The resource warning is caused by the stdlib wsgi server not closing the socket after a KeyboardInterrupt. It does not do much harm, since sockets are closed on process shutdown anyway, it is just annoying. Even after calling shutdown() on the server explicitly the warning remains. I don't see an easy way to prevent this warning other than patching the wsgiref server in the stdlib or waiting for a bugfix there.

[gfemec]

For what it's worth, fe7285893505f949b48e0f873d44c5386917b7ae (part of 0.13 development) seems to address the unclosed socket and prevents the warning for me.

[robvdl]

Yes but this was fixed 5 years ago (2014) and we're still waiting for it to be released which isn't very good.

You get the socket close warning on python 3 and bottle 0.12, I'm trying to port a project over to python 3 before the python 2 apocalypse sets in :) but bottle 0.13 is still in dev, can't this fix be backported to 0.12?

[p0lm]

Still bumping into this.

[chrism]

Getting this message too.

If anyone knows of a workaround much appreciated.

[sbargy]

Yep, I'm getting this warning, too. Hadn't seen it before, just cropped up in the last couple days. I'm investigating further to see what changed.

[robvdl]

@sbargy interesting I always thought it was running on Python 3 that did this. Have you always been on python3 or have you only recently upgraded to python3?

[franz-simonetti]

Very similar problem: when quitting a Bottle app using ^C and the built-in webserver, I get this message in the console: sys:1: ResourceWarning: unclosed <socket.socket fd=544, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('127.0.0.1', 8080)> ResourceWarning: Enable tracemalloc to get the object allocation traceback However it does not hangs, I get the command prompt directly. Python 3.8.2, Bottle v0.12.18 on Windows 10 Pro 1909 build 18363.778

[Nozavi]

Experiencing the same issue Python 3.7, Bottle v0.12.18, Windows 10 Pro 1909 build 18363.836

bottle.py:3139: ResourceWarning: unclosed <socket.socket fd=752, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('127.0.0.1', 8080)>

[sbargy]

@robvdl I've been running Python 3 on this code base since it was started.

[robvdl]

Ok it might not just be Python 3 but be something we're doing but it's irrelevant because it's happening to a LOT of people, not just me and it's not getting resolved by backporting the 0.13 fix (it should be). Bottle.py releases come out at a snails pace we've been waiting for about 5 years for 0.13, I'm trying to not be negative but it's hard, how long until 0.13 is not in beta? it's getting a bit rediculous.

Our codebase did not come up with the unclosed socket error on Python 2, but did do it on Python 3 which made me conclude it was that at the time.

The only reason we are still using bottle.py is because we're stuck with it on a legacy project, but the bottle release procedure is really slow. Bottle 0.12 came out in 2014 it's now 6 years later and 0.13 is still not out.

[robvdl]

@sbargy did you try it with autoreloading (hot reload) that triggers it. Make a code change, bottle restarts and says unclosed socket.

[x-yuri]

Debian 10 "buster", Python 3.8.3, bottle==0.12.18. It doesn't hang. The warning is only displayed in debug mode. #648 resolves the issue (for wsgiref):

--- /usr/local/bin/bottle.py    2020-07-05 12:40:20.499112052 +0000
+++ /usr/local/bin/bottle.py    2020-07-05 12:40:44.522967162 +0000
@@ -2787,7 +2787,11 @@
                     address_family = socket.AF_INET6

         srv = make_server(self.host, self.port, app, server_cls, handler_cls)
-        srv.serve_forever()
+        try:
+            srv.serve_forever()
+        except KeyboardInterrupt:
+            srv.server_close() # Prevent ResourceWarning: unclosed socket
+            raise

 class CherryPyServer(ServerAdapter):

Although the documentation recommends:

Creating a server requires several steps. First, you must create a request handler class by subclassing the BaseRequestHandler class and overriding its handle() method; this method will process incoming requests. Second, you must instantiate one of the server classes, passing it the server’s address and the request handler class. It is recommended to use the server in a with statement. Then call the handle_request() or serve_forever() method of the server object to process one or many requests. Finally, call server_close() to close the socket (unless you used a with statement).

So supposedly not a wsgiref issue.

Then, it hangs

Are you sure? Maybe just outputs the warning over the prompt?

More on it here.

[satisfaya]

GUYS! This problem is nothing to worry about. Make these changes to fix the problem: from bottle import Bottle then set app = Bottle() finally change the run command to: run(app, host='localhost', port=8080)

[qcda1]

Humm. I still have this message and I would need to know how to close the socket when the program exit the run statement. In my case, I would like to restart the web server (run statement) by sending SIGINT to the running process. By doing this, the program bomb when run is launch again as follow:

Here is the terminal session: daniel@MPDeb64:~/devel/midnite$ python 'midnitenp (copie).py' Step Start of program, duration=0.00ms Step run(host... statement, duration=0.06ms Bottle v0.12.19 server starting up (using WSGIRefServer())... Listening on http://localhost:8080/ Hit Ctrl-C to quit.

127.0.0.1 - - [17/Jan/2023 11:31:47] "GET /mesures1 HTTP/1.1" 404 736 OK received SIGINT and exited from run, waiting 10 seconds... Step Start of program, duration=0.01ms Step run(host... statement, duration=0.08ms Bottle v0.12.19 server starting up (using WSGIRefServer())... Listening on http://localhost:8080/ Hit Ctrl-C to quit.

Traceback (most recent call last): File "midnitenp (copie).py", line 113, in run(app, host='localhost', port=8080) File "/home/daniel/.local/lib/python3.7/site-packages/bottle.py", line 3137, in run server.run(app) File "/home/daniel/.local/lib/python3.7/site-packages/bottle.py", line 2789, in run srv = make_server(self.host, self.port, app, server_cls, handler_cls) File "/usr/lib/python3.7/wsgiref/simple_server.py", line 153, in make_server server = server_class((host, port), handler_class) File "/usr/lib/python3.7/socketserver.py", line 452, in init self.server_bind() File "/usr/lib/python3.7/wsgiref/simple_server.py", line 50, in server_bind HTTPServer.server_bind(self) File "/usr/lib/python3.7/http/server.py", line 137, in server_bind socketserver.TCPServer.server_bind(self) File "/usr/lib/python3.7/socketserver.py", line 466, in server_bind self.socket.bind(self.server_address) OSError: [Errno 98] Address already in use /usr/local/lib/python3.7/dist-packages/matplotlib/_pylab_helpers.py:92: ResourceWarning: unclosed <socket.socket fd=3, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('127.0.0.1', 8080)> gc.collect(1) ResourceWarning: Enable tracemalloc to get the object allocation traceback daniel@MPDeb64:~/devel/midnite$

Here is the code:

MAIN PROGRAM

while True: ts = time.time() stamp("Start of program")
stamp("run(host... statement") app = Bottle() debug(True) run(app, host='localhost', port=8080) print("OK received SIGINT and exited from run, waiting 10 seconds...") sleep(10)

print("Program end.")

Thanks for the help! Regards, Daniel.

[defnull]

This is fixed in master, but not in 0.12 yet. The wsgitef implementation does not properly clean up the socket server on SIGINT, so you could use a different server adapter that handles interrupts better, or skip the server adapter and the run() method and instead setup wsgiref.simple_server yourself. Bottles server-adapters are only a suggestion, you can simply run Bottle with wsgiref as suggested by https://github.com/bottlepy/bottle/issues/814#issuecomment-653884603

[qcda1]

Thanks very much. Couldn't see the workarounds you mentioned. Will wait next version and will try letting the Python program end at SIGINT and have a calling Bash script relaunch.