PostgreSQL Unix Domain Sockets with DATABASE_URL

[EvanCarroll]

I can connect to a database just fine using this,

let opts = PgConnectOptions::new().host("/run/postgresql").port(5432);

However, I can't figure out how to get that into DATABASE_URL, without which the macros don't work.

The docs say,

If a host name begins with a slash, it specifies Unix-domain communication rather than TCP/IP communication; the value is the name of the directory in which the socket file is stored. The default behavior when host is not specified, or is empty, is to connect to a Unix-domain socket

That doesn't seem to be true, if empty like

DATABASE_URL=postgres://:5432

I get,

error: empty host

If I try to set it to a directory,

DATABASE_URL=postgres:///run/postgresql:5432/

I get

error: error returned from database: database "run/postgresql:5432/" does not exist

[EvanCarroll]

I found the solution,

DATABASE_URL=postgres:///?port=5432&host=/run/postgresql

[jplatte]

There is no such thing as a port for a unix socket afaik, it should work the same without that.

[abonander]

For the record, Postgres does use the port for namespacing the socket file. This is likely used to allow multiple server instances to use a separate socket each.