Hello,
Writing properties, I often hesitate between using types HostName or Domain for the FQDN of a machine.
This is not 'very important' since both are "just" String, but the type carries semantics and I'd rather keep consistent (helps understanding the code better).
Here are the docs :
http://hackage.haskell.org/package/propellor-5.9.1/docs/Propellor-Types-OS.html#t:HostName http://hackage.haskell.org/package/propellor-5.9.1/docs/Propellor-Types-Dns.html#t:Domain
So HostName documentation to me looks like really corresponding to a machine's FQDN, but may also be the IP of the machine.
Conversely Domain is not documented (in its module) but it is used in the 'domain part of the FQDN' in some modules; eg. in Propellor/Property/Hostname.hs
Even clearer is the Propellor.Property.DNS module in which I clearly understand the choice of Domain vs. HostName.
Still it seems to me that sometimes one sees Domain where a HostName would be expected. One such example is in LetsEncrypt
Maybe I am just to confused by a few places where Domain is used while I would (maybe wrongly) expect HostName ?
What am I missing ?
Cheers,
Serge.
I think LetsEncrypt's use of Domain is intentional; a certificate is for a domain and you can't get one for eg a bare IP address or an unqualified hostname.
AFAICS, Domain is a FQDN.
(Propellor.Property.Hostname has to deal with details of /etc/hosts, but it does not actually use the Domain type anywhere.)
More generally, it's common for a propellor module to have some
type Foo = Stringthat's only used to make parameters more self-documenting and doesn't have any particular meaning beyond whatever string a Property might use. One shouldn't worry if two modules have data types that seem to overlap in content when that's all they're used for. Of course it's nicer to have less stringy data types, via ADTs or smart constructors, when possible.