WordPress comment_post action not working

In my plugin I want to accomplish an action after a comment is inserted into the database.

for that I use comment_post action. Here is my code

Codex: comment_post is an action triggered immediately after a comment is inserted into the database.

/*
* Plugin Fonctionalities Class
*/

class PluginFonctionalities {

    public function __construct() {
        add_action('comment_post', array('do_action_comment'));
    }

    public function do_action_comment( $comment_ID, $comment_approved ) {
        if( 1 === $comment_approved ){
            $outputFile =  plugins_url('includes/output.txt', __FILE__);
            $filehandle = fopen($outputFile, 'a') or die("File creation error.");
            fwrite($fileHandle, "Example of message");
            fclose($fileHandle);
        }
    }
}   

but nothing is happen when i submit the comment form. Any ideas !?

via Chebli Mohamed