如何从go应用程序查看postgresql“提高通知”

I'm writting small app in go. And now I need to log postgres "raise notice" message in app console.

I was not found where postgresql raised messages stored in *sql.Conn (I'm use go/sql with lib/pq driver)

example,

create function show_mes() returns int as $$
begin
     raise notice 'test message from pg';
     return 1;
end
$$ language plpgsql;

from go app I call this function and can get the result.

But how can i access to that messages "test message from pg" from go app?

In current version written in Node we log messages in console for debbugging:

thank you!

If you're using lib/pq you can use its LISTEN/NOTIFY support to achieve what you want.

On the Go side you can use something like this:

package main

import (
    "log"
    "time"

    "github.com/lib/pq"
)

func main() {
    dburl := "postgres:///?sslmode=disable"
    li := pq.NewListener(dburl, 10*time.Second, time.Minute, func(event pq.ListenerEventType, err error) {
        if err != nil {
            log.Fatal(err)
        }
    })

    if err := li.Listen("raise_notice"); err != nil {
        panic(err)
    }

    for {
        select {
        case n := <-li.Notify:
            // n.Extra contains the payload from the notification
            log.Println("notification:", n.Extra)
        case <-time.After(5 * time.Minute):
            if err := li.Ping(); err != nil {
                panic(err)
            }
        }
    }
}

Then your postgres function would look like this:

CREATE FUNCTION show_mes() RETURNS int AS $$
BEGIN
     PERFORM pg_notify('raise_notice', 'test message from pg');
     RETURN 1;
END
$$ LANGUAGE plpgsql;