Can't connect to PostgreSQL database using pgx driver but can using terminal

Question

From code

The code bellow outputs the following:

2022/06/21 16:01:07 Failed to connect to db: failed to connect to 'host=localhost user=postgres database=local': server error (FATAL: Ident authentication failed for user "postgres" (SQLSTATE 28000)) exit status 1

import (
    "context"
    "log"

    "github.com/jackc/pgx/v4"
)

func main() {
    dbCtx := context.Background()
    db, err := pgx.Connect(
        dbCtx, 
        "postgres://postgres:smashthestate@localhost:5432/local",
    )
    if err != nil {
        log.Fatalf("Failed to connect to db: %v\n", err)
    }
    defer db.Close(dbCtx)
    
    // do stuff with db...
}

From terminal

However, connection to db is possible from terminal. For example, this command if run with the same parameters (db name, user name, password) will give correct output:

psql -d local -U postgres -W -c 'select * from interest;'

Notes

1. Command works correctly even if sent by user that is neither root nor postgres.
2. Authentication method for local connection is set to trust inside pg_hba.conf:

local   all             all                                     trust

So, what am I missing here? Why everything works fine from the command line but doesn't work from code?

Answer 1

Go's defaults are different from psql's. If no hostname is given, Go defaults to using localhost, while psql defaults to using the Unix domain sockets.

To specify a Unix domain socket to Go, you need to do it oddly to get it to survive URI validation:

postgres://postgres:smashthestate@:5432/local?host=%2Ftmp

Though the end might need to be more like ?host=%2Fvar%2Frun%2Fpostgresql, depending on how the server was configured.

But why are you specifying a password which is not needed? That is going to cause pointless confusion.