If you use postgres's service feature for configuring your connections, then this is the library for you.
This is for use with the Postgres crate.
This example uses the service name mydb
and overrides
the user
value, then makes the connection.
extern crate postgres_service;
extern crate postgres;
let conn = postgres::Connection::connect(
postgres_service::load_connect_params("mydb")
.unwrap().user("your_user_name"),
postgres::TlsMode::None
).unwrap();