alarm_handler

1996 2016 Ericsson AB, All Rights Reserved Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. The Initial Developer of the Original Code is Ericsson AB. alarm_handler Martin Björklund Bjarne Dacker Bjarne Däcker Martin Björklund 1996-09-10 A alarm_handler.sgml.t1

alarm_handler An Alarm Handling Process

The alarm handler process is a gen_event event manager process that receives alarms in the system. This process is not intended to be a complete alarm handler. It defines a place to which alarms can be sent. One simple event handler is installed in the alarm handler at startup, but users are encouraged to write and install their own handlers.

The simple event handler sends all alarms as info reports to the error logger, and saves all in a list. This list can be passed to a user-defined event handler, which can be installed later. The list can grow large if many alarms are generated. This is a good reason to install a better user-defined handler.

Functions are provided to set and clear alarms. The alarm format is defined by the user. For example, an event handler for SNMP can be defined, together with an alarm Management Information Base (MIB).

The alarm handler is part of the SASL application.

When writing new event handlers for the alarm handler, the following events must be handled:

{set_alarm, {AlarmId, AlarmDescr}}

This event is generated by alarm_handler:set_alarm({AlarmId, AlarmDecsr}).

{clear_alarm, AlarmId}

This event is generated by alarm_handler:clear_alarm(AlarmId).

The default simple handler is called alarm_handler and it can be exchanged by calling gen_event:swap_handler/3 as gen_event:swap_handler(alarm_handler, {alarm_handler, swap}, {NewHandler, Args}). NewHandler:init({Args, {alarm_handler, Alarms}}) is called. For more details, see gen_event(3) in STDLIB.

clear_alarm(AlarmId) -> void() Clears the specified alarms. AlarmId = term()

Sends event clear_alarm to all event handlers.

When receiving this event, the default simple handler clears the latest received alarm with id AlarmId.

get_alarms() -> [alarm()] Gets all active alarms.

Returns a list of all active alarms. This function can only be used when the simple handler is installed.

set_alarm(alarm()) Sets an alarm with an id. alarm() = {AlarmId, AlarmDescription} AlarmId = term() AlarmDescription = term()

Sends event set_alarm to all event handlers.

When receiving this event, the default simple handler stores the alarm. AlarmId identifies the alarm and is used when the alarm is cleared.