Enrolment

I had this problem today. More than one year after, so i think it is no longer useful.

It is not possible get the user role in the event: core\event\user_enrolment_created, because Moodle deal with enrolment_created and core\event\role_assigned in different ways.

First he create the enrolment, this trigger an event core\event\user_enrolment_created at this point the user role is not defined yet.

Than he assign the role to the user, this trigger an event core\event\role_assigned. Probably this is the event you want.

//Line 1320 - File lib/enrollib.php
if ($inserted) {
            // Trigger event.
            $event = \core\event\user_enrolment_created::create(
                    array(
                        'objectid' => $ue->id,
                        'courseid' => $courseid,
                        'context' => $context,
                        'relateduserid' => $ue->userid,
                        'other' => array('enrol' => $name)
                        )
                    );
            $event->trigger();
            // Check if course contacts cache needs to be cleared.
            require_once($CFG->libdir . '/coursecatlib.php');
            coursecat::user_enrolment_changed($courseid, $ue->userid,
                    $ue->status, $ue->timestart, $ue->timeend);
        }

        if ($roleid) {
// this must be done after the enrolment event so that the role_assigned event is triggered afterwards
            if ($this->roles_protected()) {
                role_assign($roleid, $userid, $context->id, 'enrol_'.$name, $instance->id);
            } else {
                role_assign($roleid, $userid, $context->id);
            }
        }

So this is my code to get the user role:

public static function my_plugin_role_assigned(core\event\role_assigned $enrolment_data){        
        global $DB;

        //strange var name, better change it
        $enrolment_data_data = $enrolment_data->get_data();
        $snapshotid = $enrolment_data->get_data()['other']['id'];        
        $snapshot = $enrolment_data->get_record_snapshot('role_assignments', $snapshotid);

        $roleid = $snapshot->roleid;        
        $rolename = $DB->get_records_sql("SELECT shortname from {role} WHERE id = ?", array($roleid));
        $rolename = array_pop($rolename);
        $rolename = $rolename->shortname;

        if($rolename == 'editingteacher'){
            //My stuff
        }

    }

Tip: Instead of use roleid, use role shortname, because if you export something to other Moodle installation, the roleid may be different.