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The recurring pattern "drop-in code needs to have something done at startup"
is presently being solved with a variety of ad-hock mechanism. This commit
adds a general, extensible, centralized system for adding such hooks and
manages an extensible set of metadata about plugins which it collects by
searching for files named "plugin_init.rb" in a series of directories.
Initially, these are simply the $LOAD_PATH. Applications can add more places
to look for plugins without risk of adding duplicates or changing the order of
ones that have already been found with:
Puppet::Plugins.look_in(*paths)
The contents of each file found is executed in the context of a Puppet::Plugins
object (and thus scoped). An example file might contain:
-------------------------------------------------------
@name = "Greet the CA"
@description = %q{
This plugin causes a friendly greeting to print out on a master
that is operating as the CA, after it has been set up but before
it does anything.
}
def after_application_setup(options)
if options[:application_object].is_a?(Puppet::Application::Master) && Puppet::SSL::CertificateAuthority.ca?
puts "Hey, this is the CA! Hi everyone!!!"
end
end
-------------------------------------------------------
Note that the instance variables are local to this Puppet::Plugin (and so may be
used for maintaining state, etc.) but the plugin system does not provide any
thread safety assurances, so they may not be adequate for some complex use cases.
Presently supported hooks:
before_application_preinit( :application_object => ... )
after_application_preinit( :application_object => ... )
before_application_parse_options( :application_object => ... )
after_application_parse_options( :application_object => ... )
before_application_setup( :application_object => ... )
after_application_setup( :application_object => ... )
before_application_run_command( :application_object => ... )
after_application_run_command( :application_object => ... )
on_commandline_initialization(:command_line_object => ... )
on_application_initialization(:appliation_object => ... )
Paired-with: Daniel Pitman
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