Peer authentication for local connections

[mkrauss]

I can't seem to find any way to make Skunk connect to a local Postgres with "peer" authentication (https://www.postgresql.org/docs/current/auth-peer.html). This authentication type is the default out-of-the-box for local Postgres connections, on Linux, and I believe MacOS. It is convenient, and secure, for local development. It would most typically be selected by leaving out the host, username, and password, and lets the local operating system authenticate the user as the user running the connecting process. I can live without it, but was surprised to see it seems to be missing.

[mpilquist]

What errors are you seeing? AFAIK peer authentication should work fine.

[mkrauss]

It may be that I don't understand how to use it? However, I'll mention that the docs say "Skunk currently supports the trust (no password necessary), password, md5 and scram-sha-256 authentication methods." (https://typelevel.org/skunk/reference/Sessions.html), so if peer authentication is supported, the docs are out of date.

If it does work, I would expect it to work by calling, for instance, Session.single, with no host, user, or password arguments, just like invoking psql from the command line. However, while Session.single takes an Option[String] for password, the other parameters are just String.

When I try with host = "localhost", it complains that there is no password:

root[ERROR] skunk.exception.SkunkException: 
root[ERROR] 🔥  
root[ERROR] 🔥  SkunkException
root[ERROR] 🔥  
root[ERROR] 🔥    Problem: Password required.
root[ERROR] 🔥     Detail: The PostgreSQL server requested a password for 'mkrauss' but none was
root[ERROR] 🔥             given.
root[ERROR] 🔥       Hint: Specify a password when constructing your Session or Session pool.
root[ERROR] 🔥  

This is not surprising, since localhost says to connect via TCP/IP which wouldn't work for the peer auth, similar to using the cli psql -h localhost which requires a password.

When I try with host = "", it complains that the empty string isn't a valid host:

root[ERROR] skunk.exception.SkunkException: 
root[ERROR] 🔥  
root[ERROR] 🔥  SkunkException
root[ERROR] 🔥  
root[ERROR] 🔥    Problem: Hostname: "" is not syntactically valid.
root[ERROR] 🔥  

This is not surprising, either, as the empty string certainly isn't a valid host.

Am I missing something?

[mpilquist]

Oh sorry, I was incorrect. Folks have manually added in support in the past -- e.g. #928 -- but there's no current built-in support for connecting via unix domain sockets. I'd like to add it before shipping 1.0 though.

[mpilquist]

Support added in #1192