Hi John,
Thanks for the reply. Your corrections made it work. As you pointed out
about the implementation of this code. I wrote it keeping in mind 'def' of
ruby where one can return a value evaluating a block. Syntactically it
didn't have a problem with Ruby, but it failed to return a value in
puppet's case.
I am trying to implement this code to check pattern in a file, e.g.
(/etc/fstab) before puppet tries to edit it. In other words, trying to find
an equivalent of "BeginGroupIfNoLineContaining" of cfengine. This may not
be the best method though.
Cheers
On Friday, January 18, 2013 9:22:35 AM UTC-6, jcbollinger wrote:
>
>
>
> On Thursday, January 17, 2013 7:40:11 PM UTC-6, iamauser wrote:
>>
>> My custom function looks like this :
>>
>> module Puppet::Parser::Functions
>> newfunction(:pattern_in_file, :type => :rvalue) do |args|
>> filename = args[0]
>> pattern = args[1]
>> value = false
>> File.open(filename) do |f|
>> f.each_line do |line|
>> return true if line.match(pattern)
>> end
>> end
>> false
>> end
>> end
>>
>> ruby -rpuppet and irb tests to see if the function is seen by puppet end
>> successfully without any error.
>>
>> Inside the manifests callings
>> pattern_in_file('/etc/fstab', '/usr')
>> don't complain or print anything,
>>
>> If I use :
>>
>> $getval = pattern_in_file('/etc/fstab', '/usr')
>>
>> It complains the following :
>>
>> Error: Could not retrieve catalog from remote server: Error 400 on
>> SERVER: Function 'pattern_in_file' does not return a value at
>> /etc/puppet/modules/mname/manifests/datavers.pp:3 on node node_name
>>
>> Any suggestion why the return doesn't work ?
>>
>
>
> Basically, it doesn't work because the Ruby block defining your function's
> behavior (do |args| ... end) is exactly that -- a block. The 'return'
> statement does not set the value of the block; instead, it attempts to
> return from the method that evaluates the block. Without knowing any
> details about that method's implementation, it is very dangerous to make
> your block attempt to return from it. Indeed, it appears that doing so is
> the wrong thing in this case.
>
> You must instead ensure that the block evaluates to the desired value.
> For example:
>
> module Puppet::Parser::Functions
> newfunction(:pattern_in_file, :type => :rvalue) do |args|
> filename = args[0]
> pattern = args[1]
> File.open(filename) do |f|
> f.lines.any? { |line| line.match(pattern) }
> end or false
> # The "or false" converts nil to false for safety, in
> # the event that the specified file does not exist.
> end
> end
>
>
> That's cleaner and clearer anyway, at least for this example.
>
>
> John
>
>
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