So, your explanation makes sense to me - but that doesn't exactly explain to me why the "include" statement isn't enough.
E.g. when I'm "including the puppet::params class in the puppet::config class, what affect is it having at all, if not setting things like the variables included in the original puppet::params class? How can I change variables on the fly effectively, if I can't just do the import and then have the variable $puppetserver equal the one from the imported class? I'm having a hard time grasping what import does, if not this. On Saturday, August 11, 2012 10:36:48 PM UTC-4, Eric Shamow wrote: > > The best reference to explain how variable scoping works in Puppet is this > one - > > http://docs.puppetlabs.com/guides/scope_and_puppet.html > > Scoping has changed with 2.7, so you may find some confusing references > online that follow the pre-2.7 rules. In general the 2.7 changes are > designed to introduce some sanity to variable scopes and eliminate dynamic > scoping, which causes all kinds of pain. > > The easiest way to think about scoping in general is that a scope is > defined by its container. If I put something physical in a box, I have > access to it the moment I open the box, and other objects inside the box > can interact with it. If, however, I now put that box inside a second box, > the objects in the second box cannot interact directly with the objects in > the first - the first object is protected by its container. > > Scoping mostly works the same way. The right way to get at the variable is > to always explicitly scope, as you began to get at below with your > scope.lookupvar example. As that can be a bit of a pain to repeat, you can > always copy the value into a local variable: > > class puppet::config { > include puppet::params > $puppetserver = puppet::params::puppetserver > … > } > > -Eric > > -- > > Eric Shamow > Professional Services > http://puppetlabs.com/ > ©631.871.6441 > > Join us for PuppetConf 2012 at the Mission Bay Convention Center in San > Francisco, California on September 27th and 28th --> http://bit.ly/pcsig12 > > > On Saturday, August 11, 2012 at 8:45 PM, Zachary Stern wrote: > > > I'm having a really hard time grasping how variables are scoped in > > puppet (not really much of a programmer). > > > > I've got a manifest that looks like this: > > ### > > class puppet::config { > > include puppet::params > > file { '/etc/puppet/puppet.conf': > > ensure => present, > > content => template('puppet/puppet.conf.erb'), > > owner => 'root', > > group => 'admins', > > require => Class['puppet::install'], > > notify => Class['puppet::service'], > > } > > } > > ### > > > > > > I've then got a manifest like this, which has a class being included > above: > > ### > > class puppet::params { > > $puppetserver = 'command.enterawesome.com ( > http://command.enterawesome.com)' > > } > > ### > > > > The template being used in the first class includes the variable > > $puppetserver, but somehow, the include statement isn't enough for the > > variable to be defined within the scope of the manifest/template > > above. > > What gives? > > It works just fine if I include a statement like this in the erb file: > > <%= scope.lookupvar('puppet::params::puppetserver') %> > > > > But I'd really like to understand scoping better. What is it I need to > > do to just refer to the variable by name? Why isn't the include > > statement enough? Isn't in including the puppet::params class inside > > the puppet::config class, and therefore having the variable defined in > > that context? Apparently not. But I don't understand why. I wan't to > > end up at a point where the variable is in the proper scope, such that > > I can just have a statement like <%= puppetserver %> inside of the > > template I'm using. > > > > Thanks in advance! > > > > -- > > You received this message because you are subscribed to the Google > Groups "Puppet Users" group. > > To post to this group, send email to > > puppet...@googlegroups.com<javascript:>(mailto: > puppet...@googlegroups.com <javascript:>). > > To unsubscribe from this group, send email to > puppet-users...@googlegroups.com <javascript:> (mailto: > puppet-users+unsubscr...@googlegroups.com <javascript:>). > > For more options, visit this group at > http://groups.google.com/group/puppet-users?hl=en. > > > > -- 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/-/LcHGaFjy9JkJ. To post to this group, send email to puppet-users@googlegroups.com. To unsubscribe from this group, send email to puppet-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/puppet-users?hl=en.
