Implementations become Providers

After discussions, I've changed implementations to providers. This makes it easy to talk about them:

package { ssh:
    provider => rpm,
    ensure => installed
}

And the class names and instance variables all become pretty easy, too.

I've been making significant progress in the work, but as I get closer to completion, I see more and more parts of Puppet that are now code and should instead be data. For instance, unless I change things some, all of my User states will look something like this:

newstate(:gid) do
    def retrieve
        @is = provider.gid
    end

    def sync
        provider.gid = self.should
        return :user_changed
    end
end

That's basically silly. Sure, I can make a base class for User states, so that I don't have to repeat within that one class, but that's still all basically data disguised as code. I think I've got a way to be able to trim it down the basics -- the state will assume that the retrieve method is named after the state, so it knows to call provider.gid in this case, and the sync method will be basically the same.

Of course, User is a bit weird in that basically all of the states have essentially infinite valid values. Packages, on the other hand, have a fixed list of valid values, basically:

newstate(:ensure) do
    newvalue(:installed) do
        provider.install
        return :package_installed
    end
    newvalue(:absent) do ... end
    newvalue(:latest) do ... end
end

I should be able to change that code to something like this:

newstate(:ensure) do
    newvalue(:installed, :event => :package_installed, :method => :install)
    newvalue(:absent, :event => :package_removed, :method => :uninstall)
    newvalue(:latest, :event => :package_upgraded, :method => :upgrade)
end

Notice that I have the exact same information here, but it's now all presented as data.

I don't know that this is the best long-term option, and it's not quite this rosy since some methods need values and some don't, but this is what I'm searching for, anyway.

Thu, 10 Aug 2006 | Tags: puppet, providers, naming