If you don't mind the hackish-ness, I think you can just grab the file descriptor from a Zookeeper handle like this for mt -
int fd = ((int *)zhandle)[0]; This works because the fd is the first field in the _zhandle struct. Best Regards, Martin Kou On Thu, May 10, 2012 at 4:51 PM, Martin Kou <[email protected]> wrote: > I've had a similar problem as well, but I've been using the single > threaded async library - I actually find it simpler to use than the mt > library. > > The way I do it is this: > > During session connect - > 1. Grab the file descriptor from the C library via zookeeper_interest() > 2. If this is the first time I saw this file descriptor, and it's valid, > do a setsockopt() on it to set SO_NOSIGPIPE to 1. > > When I need to "suspend" the session > 1. close() the file descriptor > 2. call zookeeper_close() on the handle > > zookeeper_close() will try to send the close session message at step 2 > here. Normally, that would cause a SIGPIPE and your app would crash - but > this time it won't because you've set SO_NOSIGPIPE on the socket. Instead, > the Zookeeper library will see a regular error from its send operation and > it'll free up the handle peacefully without closing the session. > > Best Regards, > Martin Kou > > > On Thu, May 10, 2012 at 4:11 PM, Jonathan Simms <[email protected]> wrote: > >> Michi, fair point, I actually just looked into it, there doesn't seem >> to be a way through the api to re-establish the session. If you call >> zookeeper_close on the handle: >> >> "After this call, the client session will no longer be valid. The >> function will flush any outstanding send requests before return. As a >> result it may block." >> >> I tried: >> >> * establish session with handle A >> * copy clientid_t from handle A >> * zookeeper_close handle A >> * construct handle B using clientid_t values from handle A >> >> I get back a SESSION_EXPIRED from the server. (debug from mt lib here: >> https://gist.github.com/3b7e4060746d03cef287) >> >> It would be *really* useful if i could basically "suspend" a session >> while i forked, then reconnect and pick up where i left off. Is this >> not possible? >> >> On Thu, May 10, 2012 at 6:41 PM, Michi Mutsuzaki <[email protected]> >> wrote: >> > Hi Jonathan, >> > >> > It would be very difficult to share multi-threaded zk handle with >> > child process. I'm surprised it actually works on mac. I think saving >> > session id/password and re-establishing the session in the child >> > process is more robust and platform independent. >> > >> > Thanks! >> > --Michi >> >> >> > >> > On Thu, May 10, 2012 at 12:45 PM, Jonathan Simms <[email protected]> >> wrote: >> >> Hi all, >> >> >> >> I'm the maintainer of the ruby zookeeper library, and I'm having >> >> trouble getting consistent behavior when a user calls fork(). When >> >> developing it on MacOS (using 3.3.5), I was able to fork, then >> >> immediately call zookeeper_close() in the child, and then create a new >> >> handle. Testing on Linux, the behavior is much more unpredictable. >> >> Regularly, it seems there are segfaults when calling zookeeper_close. >> >> https://gist.github.com/22338464cd47e0e50970 >> >> >> >> >> >> So I guess my question is, is there any safe way to fork() while the >> >> client is running? >> >> >> >> Another possibility i thought of is to note the session id/passwd, >> >> close the client, fork, then re-open with the same id/passwd to >> >> re-establish the session in the parent. >> >> >> >> Any recommendations? >> > >
