Hello, the attached Python script can be used to reproduce the problem. No external library is necessary.
Cheers, Michele
''' Created on Mar 15, 2012 @author: Michele Mazzucco <[email protected]> ''' import sys, time, subprocess, string # backend backend = 'www' # list of servers servers_list = ['i-932dbef7', 'i-c368faa7', 'i-c968faad', 'i-cf68faab', 'i-c168faa5'] def test(sock='tmp/haproxy'): ''' * param sock: path to the socket used by HAProxy ''' enable = 'disable' while True: l = [] for i in servers_list: tmp = '%s server %s/%s' % (enable, backend, i) l.append(tmp) command = ';'.join(l) #socat = 'echo "%s" | socat stdio %s' % (command, sock) p1 = subprocess.Popen(['echo', command], stdout=subprocess.PIPE, shell=False) p2 = subprocess.Popen(['socat', 'stdio', sock], stdin=p1.stdout, shell=False, stderr=subprocess.STDOUT, stdout=subprocess.PIPE) output = p2.communicate() if p2.returncode != 0: raise RuntimeError('Unable to issue command') #socat = 'echo "show stat" | socat stdio %s' % sock # check p1 = subprocess.Popen(['echo', 'show stat'], stdout=subprocess.PIPE, shell=False) p2 = subprocess.Popen(['socat', 'stdio', sock], stdin=p1.stdout, shell=False, stderr=subprocess.STDOUT, stdout=subprocess.PIPE) output = p2.communicate() if p2.returncode != 0: raise RuntimeError('Unable to retrieve stats') res = output[0].split('\n') for line in res: if line.startswith(backend): tokens = string.split(line, ',') if tokens[1] in servers_list: # ignore BACKEND if enable == 'disable' and tokens[17] != 'MAINT': # see sec. 9.1 # http://haproxy.1wt.eu/download/1.4/doc/configuration.txt print 'Expected MAINT, got %s' % tokens[17] print line raise RuntimeError() if enable == 'enable' and tokens[17] == 'MAINT': print 'Expected not MAINT!' print line raise RuntimeError() if enable == 'enable': enable = 'disable' else: enable = 'enable' time.sleep(0.1) # the longer sleep is, the less likely the problem is likely to occur if __name__ == '__main__': sock = '/tmp/haproxy' if len(sys.argv) > 1: sock = sys.argv[1] test(sock)
On Mar 15, 2012, at 4:59 PM, Jonathan Matthews wrote: > On 15 March 2012 08:21, Michele Mazzucco <[email protected]> wrote: >> I don't think it's a problem related to the web interface -- socat behaves >> like my script, i.e., it fails to enable servers from time to time. > > Michele - > > I think the most useful thing you can do is to provide a socat > invocation that causes the problem, and let the list know how > frequently it's caused by that *exact* invocation. > Or, to put it another way, I'm not entirely sure that we're not simply > remote-debugging your script, without actually having a copy of it! > > However, it's not really in-scope for anyone on list to fix your > script, hence providing a simple command using very simple primitives > (bash; socat; etc) that we can repeat until failure occurs will really > help to clarify the failure you're observing. FWIW, I suggest you > /don't/ provide the script :-) > > All the best, > Jonathan > -- > Jonathan Matthews > London, Oxford, UK > http://www.jpluscplusm.com/contact.html
