What?

Simple types and set of functions to quickly add configuration of postgresql to your Yesod site or whatever.

How?

Add separate file or section inside your existing config like that

database:    "dbname"
host:        "127.0.0.1"       # optional
port:         5432             # optional
user:        "dbuser"
password:    "pass"
poolsize:    10               # optional maximum connections in pool
pooltimeout: 60               # optional minimum connection lifetime
poolstripes: 1                # optional count of stripes in pool

and then in your program something like that

conf <- decodeFile "pgconfig.yml"
         >>= maybe (fail "Could not parse pgconfig.yml") return
pool <- createPGPool conf
pingPGPool pool

So now you have a pool and can perform queries any way you like.