Hello Joey,

I try to setup a debomatic service on one of my computer. So I created a data which will store on which host it was installed

data DebOMaticHostMirror = DebOMaticHostMirror Url
deriving (Eq, Show, Typeable)

So now I try to create a property which get the hostname and set the info, BUT I did not find the right way to do this. Here an attempt

debomaticHostMirror :: Property (HasInfo + UnixLike)
debomaticHostMirror = property' desc $ \w -> do
  hostname <- asks hostName
  ensureProperty $ pureInfoProperty desc (InfoVal (DebOMaticHostMirror hostname))
    where
      desc = "setup the Deb-O-Matic host name for other properties"

but I get this error message

src/propellor-config.hs:935:3: error:
• Couldn't match expected type ‘Propellor Result’
              with actual type ‘Property
                                  (Propellor.Types.MetaTypes.MetaTypes inner0)
                                -> Propellor Result’
• In a stmt of a 'do' block:
    ensureProperty
    $ pureInfoProperty desc (InfoVal (DebOMaticHostMirror hostname))
  In the expression:
    do { hostname <- asks hostName;
         ensureProperty
         $ pureInfoProperty desc (InfoVal (DebOMaticHostMirror hostname)) }
  In the second argument of ‘($)’, namely
    ‘\ w
       -> do { hostname <- asks hostName;
               ensureProperty
               $ pureInfoProperty desc (InfoVal (DebOMaticHostMirror hostname)) }’

src/propellor-config.hs:935:20: error:
• Couldn't match expected type ‘OuterMetaTypesWitness outer0’
              with actual type ‘Property (HasInfo + UnixLike)’
• In the second argument of ‘($)’, namely
    ‘pureInfoProperty desc (InfoVal (DebOMaticHostMirror hostname))’
  In a stmt of a 'do' block:
    ensureProperty
    $ pureInfoProperty desc (InfoVal (DebOMaticHostMirror hostname))
  In the expression:
    do { hostname <- asks hostName;
         ensureProperty
         $ pureInfoProperty desc (InfoVal (DebOMaticHostMirror hostname)) }

the Idea after is to create a property which will take the DeboMatic Info and generate the /etc/apt/sourses.list.d/debomatic.list on a bunch of hosts.

Maybe we could have a

typeclass Mirror a where
   toSourceListDLines :: a -> [Line]

instance Mirror DebOMaticHostMirror where
   toSourceListDLines (DebOMaticHostMirror hostname) = ...

then the stdSourceListD property should be change to use toSourceListDLines

but this is another story