Alerts

Created by Trello
Last updated: Nov 08, 2017 by Petr Jůza

Alerts define metrics for watching database data and if any metric exceeds its limit then alert is activated and further operation can be executed.

Metrics are configured - the SQL query for getting count of items and limit for checking.

Examples of alerts (also with follow-up operations):

  • when count of failed messages for last 10 minutes exceeds 5 then sends email to administrators
  • when count of messages which wait for response from external system for more then 5 minutes exceeds 10 then sends email to administrators

Alerts checking is scheduled operation that is determined by ohf.alerts.repeatTime configuration parameter - checking is executed every 5 minutes by default.

Alerts configuration

There are the following configuration possibilites:

  • property files (default option)
  • JMX

Properties alerts configuration

Alerts configuration uses the same model as rest of OpenHub framework, see External configuration model 

Property file configuration format and example (from application.properties):

JMX alerts configuration

JMX configuration allows change alert limits and enable/disable selected alerts.

Reaction to alert activation

There are listeners org.openhubframework.openhub.spi.alerts.AlertListener which are called when specified alert is activated. 

There is default org.openhubframework.openhub.core.alerts.EmailAlertListenerSupport implementation that  sends email notifications to admin emails.

If you want to implement more actions and you can implement AlertListener or extends default implementation EmailAlertListenerSupport.