Re: Asyncronous, non blocking back- connector for Openldap

hptf wrote:
> Hello all,
>
> I would like to know if any of you have ever experiment a NONBLOCKING,
> socket based back-* for OpenLdap server.
>
> For obscure reasons, out of the scope of this mailing list, I must
> compile openldap slapd with non-threaded option activated.
>
> The data storage, we get data from, is accessed via standard TCP socket;
> but some read can take time. Thus we cannot wait in a blocking TCP read .
> We start our experiment with a modified version of back-sock ( using TCP
> ), but this back- use a blocking scheduling model.
> Thus,
>      How can we put in slapd scheduling loop an alien socket managed by a
> back- library ? ( SLAPD_ADD.... ?)
>      How can back- be scheduled on socket reception ( Listener* ?)

Look at the code in syncrepl.c, which does those same actions. 
connection_client_setup() and other functions are needed for this. Another 
example that uses these same functions is in the nssov overlay.

>      How can we asynchrously send LDAP response, and set the context for them

You'll need something like syncprov_op_detach() in syncprov.c.

>      What should be answered at the first ldap request ( in the
> back_search() for example) to say 'will be answered later' ?

There's no clean way to do this yet, we've been discussing a new return code 
for this purpose but haven't implemented it yet. syncprov.c does this by 
cloning the Operation so it can be re-queued, and then marking the original 
one as abandoned so that the frontend doesn't try to send any response to it 
right away.

> Any help, or pointer to help,  even for only one of this point, would be
> much appreciate!

-- 
   -- Howard Chu
   CTO, Symas Corp.           http://www.symas.com
   Director, Highland Sun     http://highlandsun.com/hyc/
   Chief Architect, OpenLDAP  http://www.openldap.org/project/