Grouper Developers Forum

[Steve Edgar <>]

Thanks for the info Gary.

The gateway does indeed do write operations, primarily adding and  
removing members from groups.

-- Steve.

On Nov 13, 2007, at 11:04 AM, GW Brown, Information Systems and  
Computing wrote:

> Hi Steve,
>
> Comments below.
>
> Gary
>
> --On 13 November 2007 10:44 -0500 Steve Edgar <>  
> wrote:
>
> > Question 1.
> >
> > Does Grouper support concurrency?  That is, can I have an instance of
> > Grouper UI running in Tomcat on one machine, and have another JVM
> > running on a different machine, running software which uses the   
> > Grouper
> > API, but points to the same db tables as the Grouper UI  instance?
> >
> > Our current AuthZ solution, called "Permit Server", was developed  
> > in  the
> > mid-90s, using an in-house protocol and hand rolled GDBM tables.    
> > It is
> > a bit short on features, but is super fast and can handle big   
> > groups.  I
> > have written a "gateway" which looks like Permit Server on  one  
> > side, and
> > talks to Grouper on the other.
> >
> > Currently, this gateway uses web services to talk to Grouper, but  
> > I  am
> > interested to know if I could instead have this gateway directly   
> > use the
> > Grouper API jars.  That would make 2 instances of the Grouper  API
> > running concurrently on 2 separate machines:
> >
> > 1) The UI
> > 2) The Gateway
> >
> > Is this practical?  If so, are there special config settings  
> > required  to
> > get the needed db locking?
>
> Grouper has no support for the type of concurrency you are talking  
> about and there has been a report of an issue at Brown (see  
> <https://bugs.internet2.edu/jira/browse/GRP-47>).
>
> The most likely problem area is when two JVMs (or threads in the  
> same JVM?) try to modify a group membership at the same time. Other  
> problems could occur if an object is deleted in a JVM (thread) and  
> another JVM (thread) has an instance of the object.
>
> Does the Gateway perform 'write' operations?
>
>
>
> ----------------------
> GW Brown, Information Systems and Computing