[Zope] Re: Zope 2.8.4 strange behavior

30 Nov 2005


      Dieter Maurer wrote:
...
Paul Winkler wrote at 2005-11-28 15:37 -0500:
...
...
...
We had to implement a keep alive mechanism to prevent our firewall
from behaving in this nasty way.
OK. Can you give a high-level summary of what you did?  I thought of
using heartbeat to detect loss of connection, but I'm not sure what I
could do on failure short of restarting Zope.
We knew that our firewall shuts down connections with a timeout
of 30 min. Thus, we have send our ZEO a keep alive message
every 20 min. The code roughly looks like this:
KeepPeriod= int(environ.get('ZEO_KEEP_ALIVE')) * 60
Storage = getConfiguration().dbtab.getDatabase('/')._storage
def keepAlive():
    LOG("CustomZODB",INFO,"Keep alive thread started")
    while 1:
        sleep(KeepPeriod)
        if Storage._ready.isSet():
            LOG("CustomZODB",INFO,"Sending keep alive message")
            Storage._load_lock.acquire()
            try:
                try:
                    Storage._server.get_info()
                    LOG("CustomZODB",INFO,"Sent keep alive message")
                except:
                    LOG("CustomZODB",ERROR,".... failed", error=exc_info())
            finally: Storage._load_lock.release()
        else:
            LOG("CustomZODB",PROBLEM,"Connection is down")
start_new_thread(keepAlive,())
Why not use the max-disconnect-poll option of the zeoclient section in 
zope.conf ?

Florent

-- 
Florent Guillaume, Nuxeo (Paris, France)   Director of R&D
+33 1 40 33 71 59   http://nuxeo.com   fg@nuxeo.com