multiple instance on Unix
Nigel King
nigel.king at orthogonsystems.com
Thu Sep 30 10:17:59 EDT 2004
On 30 Sep 2004, at 14:11, C Ginger wrote:
> I know the approach to creating a lock file has been around a long
> time but there are certain weaknesses to it. There are a number of
> race conditions in it. For instance if process A detects the directory
> isn't there it will attempt to create it. During that same time
> process B might also not find it there - since A hasn't completed its
> create yet.
This was why I created a directory rather than a file since I thought
this was supposed to be atomic.
>
> I think a better approach would be to use the shared memory option
> (see man shmop). The idea here is that each invoked instance would get
> back the same shared memory and use an appropriate atomic op to lock
> the process. Of course doing this in pure Python might be a bit
> difficult.
Thanks for all of the suggestions flooding in.
This all seems an unusual case of batteries not included.
Nigel King
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