Impersonation on two database connections

setrole.go

package main

import (
	"context"
	"database/sql"
	"fmt"
	"log"

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

func OpenDB() (*sql.DB, error) {

	// To ease SSL config ride a bit on parsing.
	cc, err := pgx.ParseConnectionString("sslmode=prefer")
	if err != nil {
		return nil, err
	}

	// Do the rest manually to allow whitespace in user/password.
	cc.Host = "192.168.56.101"
	cc.Port = 5432
	cc.User = "meta_login"
	cc.Password = "nai$Poo4Ph"
	cc.Database = "gemma"

	return stdlib.OpenDB(cc), nil
}

func must(err error) {
	if err != nil {
		log.Panicf("error: %v\n", err)
	}
}

func main() {

	db, err := OpenDB()
	must(err)
	defer db.Close()

	con1, err := db.Conn(context.Background())
	must(err)
	defer con1.Close()

	con2, err := db.Conn(context.Background())
	must(err)
	defer con2.Close()

	_, err = con1.ExecContext(context.Background(), `SELECT public.setrole_plan($1)`, "sophie")
	must(err)
	_, err = con2.ExecContext(context.Background(), `SELECT public.setrole_plan($1)`, "penka")
	must(err)

	var u1, u2 string

	err = con1.QueryRowContext(context.Background(), `SELECT current_user`).Scan(&u1)
	must(err)
	err = con2.QueryRowContext(context.Background(), `SELECT current_user`).Scan(&u2)
	must(err)

	fmt.Printf("user 1: %s\n", u1)
	fmt.Printf("user 2: %s\n", u2)
}