Processes this event.

def SendEmail(self, client_id, message):
    """Processes this event."""
    logging.info(self.logline, client_id, message)

    client_info = None
    hostname = None

    # Write crash data.
    if data_store.RelationalDBEnabled():
      client = data_store.REL_DB.ReadClientSnapshot(client_id)
      if client is not None:
        client_info = client.startup_info.client_info
        hostname = client.knowledge_base.fqdn
    else:
      client = aff4.FACTORY.Open(client_id, token=self.token)
      client_info = client.Get(client.Schema.CLIENT_INFO)
      hostname = client.Get(client.Schema.FQDN)

    crash_details = rdf_client.ClientCrash(
        client_id=client_id,
        client_info=client_info,
        crash_message=message,
        timestamp=int(time.time() * 1e6),
        crash_type="Nanny Message")

    WriteAllCrashDetails(client_id, crash_details, token=self.token)

    # Also send email.
    if config.CONFIG["Monitoring.alert_email"]:
      url = "/clients/%s" % client_id
      body = self.__class__.mail_template.render(
          client_id=client_id,
          admin_ui=config.CONFIG["AdminUI.url"],
          hostname=utils.SmartUnicode(hostname),
          signature=config.CONFIG["Email.signature"],
          url=url,
          message=utils.SmartUnicode(message))
      email_alerts.EMAIL_ALERTER.SendEmail(
          config.CONFIG["Monitoring.alert_email"],
          "GRR server",
          self.subject % client_id,
          utils.SmartStr(body),
          is_html=True)