PostgreSQL's LISTEN/NOTIFY mechanism can be used with Go to implement a simple publish/subscribe (pub/sub) system for inter-process communication.

listen.go

package main

import (
    "context"
    "fmt"
    "log"

    "://github.com"
    "://github.com/pgconn"
)

func main() {
    ctx := context.Background()
    connStr := "postgresql://user:password@localhost:5432/dbname"

    // 1. Establish a dedicated connection for listening
    conn, err := pgx.Connect(ctx, connStr)
    if err != nil {
        log.Fatal("Unable to connect to database:", err)
    }
    defer conn.Close(ctx)

    // 2. Start listening on a specific channel
    _, err = conn.Exec(ctx, "LISTEN events")
    if err != nil {
        log.Fatal("Error listening to channel:", err)
    }
    fmt.Println("Listening for notifications on 'events' channel...")

    // 3. Wait for notifications in a loop
    for {
        notification, err := conn.WaitForNotification(ctx)
        if err != nil {
            log.Fatal("Error waiting for notification:", err)
        }

        fmt.Printf("Received notification on channel '%s': %s (PID: %d)\n",
            notification.Channel, notification.Payload, notification.PID)
        
        // Process the payload, e.g., unmarshal JSON
        // var data map[string]interface{}
        // json.Unmarshal([]byte(notification.Payload), &data)
        // ...
    }
}

notify.sql

CREATE OR REPLACE FUNCTION notify_event() RETURNS TRIGGER AS $$
DECLARE
    notification JSON;
BEGIN
    -- Build a JSON payload with table, action, and data
    notification := json_build_object(
        'table', TG_TABLE_NAME,
        'action', TG_OP,
        'data', row_to_json(NEW)
    );
    -- Notify the 'events' channel with the JSON payload
    PERFORM pg_notify('events', notification::text);
    RETURN NULL;
END;
$$ LANGUAGE plpgsql;

trigger.sql

CREATE TRIGGER users_after_update_trigger
AFTER INSERT OR UPDATE OR DELETE ON users
FOR EACH ROW EXECUTE PROCEDURE notify_event();