With Puppet 2.6.x we do not have a way to specify containment
relationships. In the use case of class ntp { } declaring
ntp::{package,config,service} classes, the ntp class itself should allow
the user to specify before and require relationships to the main ntp
class.
The anchor resource type allows module authors to close the loop on
classes composing the main top level module. For example:
class ntp {
class { 'ntp::package': }
-> class { 'ntp::config': }
-> class { 'ntp::service': }
# These two resources "anchor" the composed classes
# such that the end user may use "require" and "before"
# relationships with Class['ntp']
anchor { 'ntp::begin': } -> class { 'ntp::package': }
class { 'ntp::service': } -> anchor { 'ntp::end': }
}
Using this pattern, the module user may then simply declare relationships to
the ntp class as they expect:
class { 'ntp': } -> class { 'mcollective': }
# OR
class { 'mcollective': } -> class { 'ntp': }
This function aborts catalog compilation if any of the passed
values are not true or false. Note, this catches the string
values of true and false correct and will abort catalog
compilation if they are not boolean values.
Paired-with: Dan Bode <dan@puppetlabs.com>
While developing Puppet Modules with class parameters, data from the
user should be validated as per the Style Guide. Puppet should fail
early and hard in the situation of invalid data being passed into the
module.
This function provides a more concise method to the alternative of using
if statements in the Puppet manifests.
