Re: [Puppet Users] variable scoping?
>
> Sorry, that should be
>
> $puppetserver = $puppet::params::puppetserver
>
> -Eric
>
>
Seems like at that point I may as well just do this inside the template:
<%= scope.lookupvar('puppet::params::puppetserver') %>
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Re: [Puppet Users] variable scoping?
Also, fwiw, I've read that document on scoping beginning to end several
times. Doesn't mean much to me I'm afraid - pretty new to all 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(mailto:
> puppet...@googlegroups.com ).
> > To unsubscribe from this group, send email to
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> puppet-users+unsubscr...@googlegroups.com ).
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>
>
>
>
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Re: [Puppet Users] variable scoping?
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(mailto:
> puppet...@googlegroups.com ).
> > To unsubscribe from this group, send email to
> puppet-users...@googlegroups.com (mailto:
> puppet-users+unsubscr...@googlegroups.com ).
> > For more options, visit this group at
> http://groups.google.com/group/puppet-users?hl=en.
>
>
>
>
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Re: [Puppet Users] variable scoping?
>
> Sorry typo:
>
> class puppet (
> $server = $puppet::params::server
> ) inherits puppet::params {
>
>
FWIW, this works:
class puppet::config {
include puppet::params
$puppetserver=$puppet::params::puppetserver
$runinterval=$puppet::params::runinterval
file { '/etc/puppet/puppet.conf':
ensure => present,
content => template('puppet/puppet.conf.erb'),
require => Class['puppet::install'],
notify => Class['puppet::service'],
}
}
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[Puppet Users] Re: variable usage in a string, scenario dependent?
It turns out that you do always need the {}, and this just works because
the / in the path breaks the variable-finding regex.
Thanks to rodjek on irc! :-D
On Saturday, September 22, 2012 3:15:07 PM UTC-4, Zachary Alex Stern wrote:
>
> Possibly stupid question - how do I know when I have to use a variable
> in a string like this - "${apache::params::moddir}/php.conf" - or when
> it's safe to just do it like this -
> "$apache::params::moddir/php.conf". It seems like sometimes I need to
> do the former, and other times the latter.
>
> I don't really have any prior programming knowledge - I feel like this
> would be obvious if I did. :-(
>
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