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 ?
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Any words/thoughts/suggestions/hints/ideas/pointers ? -- You received this message because you are subscribed to the Google Groups "Puppet Users" group. To view this discussion on the web visit https://groups.google.com/d/msg/puppet-users/-/aoLp9yEJ1T4J. To post to this group, send email to puppet-users@googlegroups.com. To unsubscribe from this group, send email to puppet-users+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/puppet-users?hl=en.
jcbollinger
2013-Jan-18 15:22 UTC
[Puppet Users] Re: Error: Function does not return a value
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 -- You received this message because you are subscribed to the Google Groups "Puppet Users" group. To view this discussion on the web visit https://groups.google.com/d/msg/puppet-users/-/4jvwgp0O9TQJ. To post to this group, send email to puppet-users@googlegroups.com. To unsubscribe from this group, send email to puppet-users+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/puppet-users?hl=en.
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 > >-- You received this message because you are subscribed to the Google Groups "Puppet Users" group. To view this discussion on the web visit https://groups.google.com/d/msg/puppet-users/-/3QQ67F7g9vkJ. To post to this group, send email to puppet-users@googlegroups.com. To unsubscribe from this group, send email to puppet-users+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/puppet-users?hl=en.
jcbollinger
2013-Jan-18 19:44 UTC
[Puppet Users] Re: Error: Function does not return a value
On Friday, January 18, 2013 10:08:49 AM UTC-6, iamauser wrote:> > 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. > >Not only is it not the best method, it is not a viable method. Puppet functions are evaluated on the master, with no visibility on client details other than anything passed as arguments. You need something that runs on the client. You might want to look into augeas for editing the file. Alternatively, it would be closer to your current design to implement and use a custom fact. If you are modifying the file via an Exec, then use grep in its ''onlyif'' or ''unless'' parameter. There are other alternatives, too. John -- You received this message because you are subscribed to the Google Groups "Puppet Users" group. To view this discussion on the web visit https://groups.google.com/d/msg/puppet-users/-/odHP-E72V44J. To post to this group, send email to puppet-users@googlegroups.com. To unsubscribe from this group, send email to puppet-users+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/puppet-users?hl=en.