Puppet users - May 2007 - Exception handling in custom facts

Hi.

I''d like to use exception handling in my custom facts.  For example, in
plain Ruby:

begin
    buildno = ''''
    bcrelease = open("/etc/BCrelease")
    while (line = bcrelease.gets)
        line = line.chomp
        buildno = $1 if line =~ /^Build:\s+(\d+)/
    end
    bcrelease.close
    print "#{buildno}\n"
rescue
    print "No file?\n"
end

Works fine.  However, in a custom fact the rescue clause doesn''t quite
do it for me:

Facter.add("buildno") do
    setcode do
        begin
            buildno = ''''
            bcrelease = open("/etc/BCrelease")
            while (line = bcrelease.gets)
                line = line.chomp
                buildno = $1 if line =~ /^Build:\s+(\d+)/
            end
            bcrelease.close
            buildno
        rescue
            print "XXX: No such file?\n"
            ''''
        end
    end
end

# puppetd -tov --noop --test          
info: Loading fact buildno
XXX: No such file?
err: No such file or directory - /etc/BCrelease

So we -_do_ get the exception handled, however Puppet aborts anyway :-(

The err: line is the contents of $!

How do I persuade facter that it''s not an error to abort on?

Best regards,
Derek
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On May 11, 2007, at 10:24 AM, <Derek.Whayman@barclayscapital.com>  
<Derek.Whayman@barclayscapital.com> wrote:
[...]
> # puppetd -tov --noop --test
> info: Loading fact buildno
> XXX: No such file?
> err: No such file or directory - /etc/BCrelease
>
> So we -_do_ get the exception handled, however Puppet aborts  
> anyway :-(
>
> The err: line is the contents of $!
>
> How do I persuade facter that it''s not an error to abort on?
Umm, this is news to me.  I just tried it locally:

Facter.add("failure") do
     setcode do
         begin
             File.open("/no/such/file") do |f|
                 f.read
             end
          rescue => detail
             ""
         end
      end
  end

It seems to behave correctly -- I get no result back -- but I''m using  
this from Facter, not within Puppet.

Either way, though, Facter shouldn''t have any idea that an exception  
was caught, and I wouldn''t expect I could figure get the behaviour  
you''re seeing even if I wanted to.

In other words, I''m pretty confused.

  --
  If two men agree on everything, you may be sure that one of them is
  doing the thinking.    -- Lyndon B. Johnson
  ---------------------------------------------------------------------
  Luke Kanies | http://reductivelabs.com | http://madstop.com

Well it was a Friday afternoon.  This is working for me now - with my
original code?!?

Blech.

Derek

-----Original Message-----
From: puppet-users-bounces@madstop.com
[mailto:puppet-users-bounces@madstop.com] On Behalf Of Luke Kanies
Sent: 11 May 2007 17:55
To: Puppet User Discussion
Subject: Re: [Puppet-users] Exception handling in custom facts

On May 11, 2007, at 10:24 AM, <Derek.Whayman@barclayscapital.com>
<Derek.Whayman@barclayscapital.com> wrote:
[...]
> # puppetd -tov --noop --test
> info: Loading fact buildno
> XXX: No such file?
> err: No such file or directory - /etc/BCrelease
>
> So we -_do_ get the exception handled, however Puppet aborts anyway 
> :-(
>
> The err: line is the contents of $!
>
> How do I persuade facter that it''s not an error to abort on?
Umm, this is news to me.  I just tried it locally:

Facter.add("failure") do
     setcode do
         begin
             File.open("/no/such/file") do |f|
                 f.read
             end
          rescue => detail
             ""
         end
      end
  end

It seems to behave correctly -- I get no result back -- but I''m using
this from Facter, not within Puppet.

Either way, though, Facter shouldn''t have any idea that an exception
was
caught, and I wouldn''t expect I could figure get the behaviour
you''re
seeing even if I wanted to.

In other words, I''m pretty confused.

  --
  If two men agree on everything, you may be sure that one of them is
  doing the thinking.    -- Lyndon B. Johnson
  ---------------------------------------------------------------------
  Luke Kanies | http://reductivelabs.com | http://madstop.com


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------------------------------------------------------------------------
For important statutory and regulatory disclosures and more information about
Barclays Capital, please visit our web site at http://www.barcap.com.

Internet communications are not secure and therefore the Barclays Group does not
accept legal responsibility for the contents of this message.  Although the
Barclays Group operates anti-virus programmes, it does not accept responsibility
for any damage whatsoever that is caused by viruses being passed.  Any views or
opinions presented are solely those of the author and do not necessarily
represent those of the Barclays Group.  Replies to this email may be monitored
by the Barclays Group for operational or business reasons.

Barclays Capital is the investment banking division of Barclays Bank PLC, a
company registered in England (number 1026167) with its registered office at 1
Churchill Place, London, E14 5HP. This email may relate to or be sent from other
members of the Barclays Group.
------------------------------------------------------------------------

On May 14, 2007, at 3:16 AM, <Derek.Whayman@barclayscapital.com> wrote:
> Well it was a Friday afternoon.  This is working for me now - with my
> original code?!?
I hate that, but at least it''s working. :/

  --
  If a `religion'' is defined to be a system of ideas that contains
  unprovable statements, then Godel taught us that mathematics is not
  only a religion, it is the only religion that can prove itself to be
  one. 					-- John Barrow
  ---------------------------------------------------------------------
  Luke Kanies | http://reductivelabs.com | http://madstop.com