pgx connection functions (with and without app name, with and without pool)

local_db.go

package database

import (
	"context"
	"fmt"
	"os"

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

const URL = "postgres://andrew:fakepassword@localhost:5432/postgres?application_name=test_name"
const URL_NONAME = "postgres://andrew:fakepassword@localhost:5432/postgres"

func ConnWithName() int {
	conn, err := pgx.Connect(context.Background(), URL)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to connect to database: %v\n", err)
		os.Exit(1)
	}
	defer conn.Close(context.Background())
	var count int
	sql := "SELECT count(*) FROM pg_stat_activity WHERE state = 'active' OR state = 'idle';"
	err = conn.QueryRow(context.Background(), sql).Scan(&count)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to get count: %v\n", err)
		os.Exit(1)
	} else {
		fmt.Fprintf(os.Stdout, "Got count %d\n", count)
	}
	return count
}

func ConnWithoutName() int {
	conn, err := pgx.Connect(context.Background(), URL_NONAME)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to connect to database: %v\n", err)
		os.Exit(1)
	}
	defer conn.Close(context.Background())
	var count int
	sql := "SELECT count(*) FROM pg_stat_activity WHERE state = 'active' OR state = 'idle';"
	err = conn.QueryRow(context.Background(), sql).Scan(&count)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to get count: %v\n", err)
		os.Exit(1)
	} else {
		fmt.Fprintf(os.Stdout, "Got count %d\n", count)
	}
	return count
}

func PoolWithName() int {
	pool, err := pgxpool.Connect(context.Background(), URL)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to connect to database: %v\n", err)
		os.Exit(1)
	}
	defer pool.Close()
	var count int
	sql := "SELECT count(*) FROM pg_stat_activity WHERE state = 'active' OR state = 'idle';"
	err = pool.QueryRow(context.Background(), sql).Scan(&count)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to get count: %v\n", err)
		os.Exit(1)
	} else {
		fmt.Fprintf(os.Stdout, "Got count %d\n", count)
	}
	return count
}

func PoolWithoutName() int {
	pool, err := pgxpool.Connect(context.Background(), URL_NONAME)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to connect to database: %v\n", err)
		os.Exit(1)
	}
	defer pool.Close()
	var count int
	sql := "SELECT count(*) FROM pg_stat_activity WHERE state = 'active' OR state = 'idle';"
	err = pool.QueryRow(context.Background(), sql).Scan(&count)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Unable to get count: %v\n", err)
		os.Exit(1)
	} else {
		fmt.Fprintf(os.Stdout, "Got count %d\n", count)
	}
	return count
}