Puppet users - Jun 2013 - Exec onlyif/unless with internal functions instead of external commands?

Hi,

A little annoyance about "exec" that bothers me is that there is no
way to
use "unless"/"onlyif" except with external commands, even if
a simple Ruby
function could be used to execute the test.

e.g. "onlyif => ''test -d /data''" will fork and
exec "test" to do a simple
stat(2) which can be done with much less overhead with Ruby''s 
"File.directory?(''/data'')".

How about allowing passing a none-string value to Exec''s onlyif/unless 
attributes, and consider that as the result? If it''s a string then it
will
be treated as today, otherwise it will be treated as a boolean.

I don''t think this will break any backward compatibility since all
Exec''s
currently expect strings to execute.

Cheers,

--Amos

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Take a look at http://docs.puppetlabs.com/guides/custom_functions.html you 
could write your own fuctions to give you something like this.

Puppet hasn''t really been designed to be low overhead (with more of a
focus
on simplicity) and i think the least of it''s performance problems come
from
the fact that it uses an external fork for exec checks.

On Sunday, June 23, 2013 8:39:57 PM UTC+10, Amos Shapira
wrote:
>
> Hi,
>
> A little annoyance about "exec" that bothers me is that there is
no way to
> use "unless"/"onlyif" except with external commands,
even if a simple Ruby
> function could be used to execute the test.
>
> e.g. "onlyif => ''test -d /data''" will fork
and exec "test" to do a simple
> stat(2) which can be done with much less overhead with Ruby''s 
> "File.directory?(''/data'')".
>
> How about allowing passing a none-string value to Exec''s
onlyif/unless
> attributes, and consider that as the result? If it''s a string then
it will
> be treated as today, otherwise it will be treated as a boolean.
>
> I don''t think this will break any backward compatibility since all
Exec''s
> currently expect strings to execute.
>
> Cheers,
>
> --Amos
>
>
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Functions are executed on the master, not on the agent, so they won''t
do
what you need.

If you really want to run code on the client it has to be a type/provider.

If it is only "test -e", use "File%creates".

Regards, David

On 24.06.2013 03:59, Michael Dodwell wrote:
> Take a look at
> http://docs.puppetlabs.com/guides/custom_functions.html you could write
> your own fuctions to give you something like this.
>
> Puppet hasn''t really been designed to be low overhead (with more
of a
> focus on simplicity) and i think the least of it''s performance
problems
> come from the fact that it uses an external fork for exec checks.
>
> On Sunday, June 23, 2013 8:39:57 PM UTC+10, Amos Shapira wrote:
>
>     Hi,
>
>     A little annoyance about "exec" that bothers me is that there
is no
>     way to use "unless"/"onlyif" except with external
commands, even if
>     a simple Ruby function could be used to execute the test.
>
>     e.g. "onlyif => ''test -d /data''" will
fork and exec "test" to do a
>     simple stat(2) which can be done with much less overhead with
Ruby''s
>     "File.directory?(''/data'')".
>
>     How about allowing passing a none-string value to Exec''s
>     onlyif/unless attributes, and consider that as the result? If
it''s a
>     string then it will be treated as today, otherwise it will be
>     treated as a boolean.
>
>     I don''t think this will break any backward compatibility since
all
>     Exec''s currently expect strings to execute.
>
>     Cheers,
>
>     --Amos
>
> --
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> Groups "Puppet Users" group.
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> an email to puppet-users+unsubscribe@googlegroups.com.
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>
>
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Response inline.

On Monday, 24 June 2013 11:59:06 UTC+10, Michael Dodwell
wrote:
>
> Take a look at http://docs.puppetlabs.com/guides/custom_functions.html you 
> could write your own fuctions to give you something like this.
>
> Thanks Michael.
I was hoping to add such a functionality to Puppet.

 
> Puppet hasn''t really been designed to be low overhead (with more
of a
> focus on simplicity) and i think the least of it''s performance
problems
> come from the fact that it uses an external fork for exec checks.
>
I hope that''s not Puppetlabs'' view on performance. Performance
and resource
optimisation should be up there at the top of the feature list just like 
security.

> On Sunday, June 23, 2013 8:39:57 PM UTC+10, Amos Shapira wrote:
>>
>> Hi,
>>
>> A little annoyance about "exec" that bothers me is that there
is no way
>> to use "unless"/"onlyif" except with external
commands, even if a simple
>> Ruby function could be used to execute the test.
>>
>> e.g. "onlyif => ''test -d /data''" will
fork and exec "test" to do a simple
>> stat(2) which can be done with much less overhead with Ruby''s 
>> "File.directory?(''/data'')".
>>
>> How about allowing passing a none-string value to Exec''s
onlyif/unless
>> attributes, and consider that as the result? If it''s a string
then it will
>> be treated as today, otherwise it will be treated as a boolean.
>>
>> I don''t think this will break any backward compatibility since
all Exec''s
>> currently expect strings to execute.
>>
>> Cheers,
>>
>> --Amos
>>
>>
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On Monday, 24 June 2013 15:40:14 UTC+10, David Schmitt wrote:
> Functions are executed on the master, not on the agent, so they
won''t do
> what you need. 
>
Yes I keep forgetting that.
>
> If you really want to run code on the client it has to be a type/provider. 
>
I was hoping to get something like to be considered to be built into 
Puppet. 
>
> If it is only "test -e", use "File%creates". 
>
I know about "creates" parameter, but there are other tests which
could be
easily done with a ruby function/system-call (e.g. file size, type, content 
etc). 

> Regards, David 
>
> On 24.06.2013 03:59, Michael Dodwell wrote: 
> > Take a look at 
> > http://docs.puppetlabs.com/guides/custom_functions.html you could
write
> > your own fuctions to give you something like this. 
> > 
> > Puppet hasn''t really been designed to be low overhead (with
more of a
> > focus on simplicity) and i think the least of it''s
performance problems
> > come from the fact that it uses an external fork for exec checks. 
> > 
> > On Sunday, June 23, 2013 8:39:57 PM UTC+10, Amos Shapira wrote: 
> > 
> >     Hi, 
> > 
> >     A little annoyance about "exec" that bothers me is that
there is no
> >     way to use "unless"/"onlyif" except with
external commands, even if
> >     a simple Ruby function could be used to execute the test. 
> > 
> >     e.g. "onlyif => ''test -d /data''"
will fork and exec "test" to do a
> >     simple stat(2) which can be done with much less overhead with
Ruby''s
> >     "File.directory?(''/data'')". 
> > 
> >     How about allowing passing a none-string value to Exec''s 
> >     onlyif/unless attributes, and consider that as the result? If
it''s a
> >     string then it will be treated as today, otherwise it will be 
> >     treated as a boolean. 
> > 
> >     I don''t think this will break any backward compatibility
since all
> >     Exec''s currently expect strings to execute. 
> > 
> >     Cheers, 
> > 
> >     --Amos 
> > 
> > -- 
> > You received this message because you are subscribed to the Google 
> > Groups "Puppet Users" group. 
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> > an email to puppet-users...@googlegroups.com <javascript:>. 
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puppet...@googlegroups.com<javascript:>.
>
> > Visit this group at http://groups.google.com/group/puppet-users. 
> > For more options, visit https://groups.google.com/groups/opt_out. 
> > 
> > 
>
>
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