Re: remote calls and success/fail?

[Jamie C. <jca...@we...>]

Joe Cooper wrote:
> 
> Hi Jamie,
> 
> I've begun to implement DNS record creation using remote_foreign_call,
> and in an attempt to code 'correctly' from the beginning, I'm trying to
> figure out how to do error checking, or at least some form of
> success/fail checking on the remote call.
> 
> Any pointers on how this should be done?  I see that the create_record
> routine (and pretty much all the rest) don't return anything
> explicitly...So I'm guessing this is one of those things that perl
> probably does implicitly in some magical manner, but I'm not real sure
> where to look to figure out the magic.
> 
> So, my question is:  Can I check for success/fail on a
> remote_foreign_call?  If so, how?

There are really 2 kinds of failure that you need to check for - failure
to connect to the remote server, and failure of the remote function. In
the first case, the &remote_foreign_call function will call perl's die
statement if anything goes wrong, which will usually cause your script
to exit. To trap this, use eval like so :

$rv = eval { &remote_foreign_call(....) }
if ($@) {
	# failed to connect or login to the remote webmin server
	}

The second thing you might need to check for is the return value of
the remote function, which will just be returned by &remote_foreign_call .
Though in the case you mentioned above (DNS record creation) there is no
meaningful return value even if the DNS record wasn't saved for some
reason, such as a lack of disk space.

 - Jamie