Python socket.timeout

Question

I am running a script at boot and continuously every second written in Python. It works fine for a limited amount of time (seems to vary ~5/10 mins) and then produced the following error bellow.

I have not tried changing the sleep time as this is a "test" script but I will be using scripts that must run every second so trying to find the right way to do it.

Google seems to yield little in the way of answers, perhaps I am using the wrong terms but I am not sure its the sleep time possibly a failure pinging the IP?

PYTHON

import time, urllib2

def internet_on():
    try:
        response=urllib2.urlopen('http://64.233.160.94',timeout=1)
        return '<img class="right" src="networkon.png" width="32" height="32">'
    except urllib2.URLError as err: pass
    return '<img class="right" src="networkoff.png" width="32" height="32">'

output = internet_on()    
f = open('/var/www/html/viv/wifiout.html', 'w')
print >> f, output
f.close()

time.sleep(1)

while True:
    internet_on()

HTML

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Vivarium Enviroment Control Centre</title>
<link rel="stylesheet" href="style.css">
<script src="https://code.jquery.com/jquery-1.12.0.min.js"></script>
<script type="text/javascript">
    function updateTime() {
        var currentTime = new Date();
        var hours = currentTime.getHours();
        var minutes = currentTime.getMinutes();
        var seconds = currentTime.getSeconds();
        if (minutes < 10){
            minutes = "0" + minutes;
        }
        if (seconds < 10){
            seconds = "0" + seconds;
        }
        var v = hours + ":" + minutes + ":" + seconds + " ";
        if(hours > 11){
            v+="PM";
        } else {
            v+="AM"
        }
        setTimeout("updateTime()",1000);
        document.getElementById('time').innerHTML=v;
    }

  $("document").ready(function(){
        updateTime();

        setInterval(function(){
          $("#wifi").load('wifiout.html');
        },1000);
      });

function changeStatus() {
    var image = document.getElementById('lightStatus');
    if (image.src.match("lightoff")) {
        image.src = "lighton.png";
    } else {
        image.src = "lightoff.png";
    }
}
</script>
</head>
<body>
<div id="topbar">
    <span id="time"></span>
    <span id="wifi"></span>
    <img id="lightStatus" class="right" onclick="changeStatus()" src="lightoff.png" width="32" height="32">
</div>
</body>
</html>

ERROR THROWN AFTER RUNNING FOR A WHILE

pi@Vivarium:~ $ sudo python /home/pi/Desktop/wifi.py
Traceback (most recent call last):
  File "/home/pi/Desktop/wifi.py", line 17, in <module>
    internet_on()
  File "/home/pi/Desktop/wifi.py", line 8, in internet_on
    urllib2.urlopen('http://64.233.160.94',timeout=1)
  File "/usr/lib/python2.7/urllib2.py", line 154, in urlopen
    return opener.open(url, data, timeout)
  File "/usr/lib/python2.7/urllib2.py", line 437, in open
    response = meth(req, response)
  File "/usr/lib/python2.7/urllib2.py", line 550, in http_response
    'http', request, response, code, msg, hdrs)
  File "/usr/lib/python2.7/urllib2.py", line 469, in error
    result = self._call_chain(*args)
  File "/usr/lib/python2.7/urllib2.py", line 409, in _call_chain
    result = func(*args)
  File "/usr/lib/python2.7/urllib2.py", line 656, in http_error_302
    return self.parent.open(new, timeout=req.timeout)
  File "/usr/lib/python2.7/urllib2.py", line 437, in open
    response = meth(req, response)
  File "/usr/lib/python2.7/urllib2.py", line 550, in http_response
    'http', request, response, code, msg, hdrs)
  File "/usr/lib/python2.7/urllib2.py", line 469, in error
    result = self._call_chain(*args)
  File "/usr/lib/python2.7/urllib2.py", line 409, in _call_chain
    result = func(*args)
  File "/usr/lib/python2.7/urllib2.py", line 656, in http_error_302
    return self.parent.open(new, timeout=req.timeout)
  File "/usr/lib/python2.7/urllib2.py", line 431, in open
    response = self._open(req, data)
  File "/usr/lib/python2.7/urllib2.py", line 449, in _open
    '_open', req)
  File "/usr/lib/python2.7/urllib2.py", line 409, in _call_chain
    result = func(*args)
  File "/usr/lib/python2.7/urllib2.py", line 1227, in http_open
    return self.do_open(httplib.HTTPConnection, req)
  File "/usr/lib/python2.7/urllib2.py", line 1200, in do_open
    r = h.getresponse(buffering=True)
  File "/usr/lib/python2.7/httplib.py", line 1073, in getresponse
    response.begin()
  File "/usr/lib/python2.7/httplib.py", line 415, in begin
    version, status, reason = self._read_status()
  File "/usr/lib/python2.7/httplib.py", line 371, in _read_status
    line = self.fp.readline(_MAXLINE + 1)
  File "/usr/lib/python2.7/socket.py", line 476, in readline
    data = self._sock.recv(self._rbufsize)
socket.timeout: timed out

Your problem seems to be related to lack of connection, which could be one of 2 issues: proxy or lack of responsiveness from the target server. The first issue is related to the fact that a script in python does not use the credentials on the machine, thus, if you have a proxy on your way, it will not authenticate and give the error. — Walter_Ritzel, Apr 04 '16 at 16:47
Well no proxy setup or used so target server issue. What would be the cause? That is the IP for Google, so I used it assuming it wouldn't cause issues because of Google's size. — Sauced Apples, Apr 04 '16 at 16:48
So, are you completely sure that the network you are using does not require proxy? Because this is a very common issue in corporate networks. — Walter_Ritzel, Apr 04 '16 at 16:49
I'm at home. But I do get the very same issue and timings both at work and home. — Sauced Apples, Apr 04 '16 at 16:51
do you realize that the python script you have provided overrides your html file with a single `` tag that the function returns then continuously tries to retrieve the data until it takes more then a second to actually retrieve the data? You are almost certainly putting huge strain on the network connection it is very likely it takes more then a second because the server needs some time to flush some catches, how many times does `internet_on()` run in the while loop before it gives you the error? — Tadhg McDonald-Jensen, Apr 04 '16 at 16:55
Looking more closely to your code, I think it has some mistakes that may be leading to a non-intentional DDOS. Let me publish an answer for that. — Walter_Ritzel, Apr 04 '16 at 16:56
@TadhgMcDonald-Jensen I will double check now but 18 cycles I'm sure of it. — Sauced Apples, Apr 04 '16 at 16:57
@Walter_Ritzel that's a good possibility. Fortunately the finial "idea" will be running every second on local hardware off-network. — Sauced Apples, Apr 04 '16 at 16:57
@SaucedApples is there a reason you are trying to make a full request instead of [just getting the HEAD data](http://stackoverflow.com/a/16778473/5827215) to check if the target can be reached? — Tadhg McDonald-Jensen, Apr 04 '16 at 17:13
Not particularly. I was more focused on seeing if a script could be ran every second. — Sauced Apples, Apr 04 '16 at 17:15

Walter_Ritzel · Accepted Answer · 2016-04-04T17:02:33.697

1

Try this:

import time, urllib2

def internet_on():
    returnValue = '<img class="right" src="networkon.png" width="32" height="32">'
    try:
        response=urllib2.urlopen('http://64.233.160.94',timeout=1)
    except:
        returnValue = '<img class="right" src="networkoff.png" width="32" height="32">'
    return returnValue


while True:
    output = internet_on()
    with open('/var/www/html/viv/wifiout.html', 'w') as f:
        f.write(output)
    time.sleep(5)

edited Apr 04 '16 at 17:02

answered Apr 04 '16 at 17:00

Walter_Ritzel

1,387
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time.sleep takes an argument in seconds, why are you waiting 1000 seconds? – Tadhg McDonald-Jensen Apr 04 '16 at 17:00
Looks like JQuery `1000` eh? Ha OK let me try it out. – Sauced Apples Apr 04 '16 at 17:01
1

I juat fixed to only 5 seconds, which should be a good time for the network to breath a little between connections. – Walter_Ritzel Apr 04 '16 at 17:03
@Walter_Ritzel well the script is running! Unfortunately it will be a case of give it a while and then click the tick. Then leave it overnight and see if it's still running but like you say, 5 seconds should be enough. Thank you. – Sauced Apples Apr 04 '16 at 17:08
@Walter_Ritzel I have been testing some ways to lose/join the network and I've found it no longer seems to run the script correctly if there is no network when the script is ran by root on boot. Can I use my own script and just change the sleep time do you think? – Sauced Apples Apr 04 '16 at 17:30
In fact, you cannot use your original script because the loop on it just call the function to access thr url, but does not do anything with it. If you get my script, it will work exactly as you need, evaluating and saving the file every 5 seconds. – Walter_Ritzel Apr 04 '16 at 18:22

Python socket.timeout

1 Answers1