How can we camunda generate logs using history service?

[bharat...@gmail.com]

Can camunda generates logs at the same time while writing audit and full process information into history data tables?

Thanks,
Kumar

[Philipp Ossler]

Hi Kumar,

you can use a custom history backend to create logs additionally, see [1]. 

For example, you can extend the HistoryEventHandler to create the log entry and the data base entries, as default.

Greetings,

Philipp

[1] http://docs.camunda.org/manual/7.3/guides/user-guide/#process-engine-history-and-audit-event-log-providing-a-custom-history-backend

[bharat...@gmail.com]

Thanks Philipp for providing this information.

Could you please provide me an example to create log entry using history service?

Thanks
Kumar

[bharat...@gmail.com]

Hi Philipp,

i added historyeventhandler to applicationContext.xml file and running as shown below.

<bean id="processEngineConfiguration" class="org.camunda.bpm.engine.spring.SpringProcessEngineConfiguration">
<property name="processEngineName" value="default" />
<property name="dataSource" ref="dataSource" />
<property name="transactionManager" ref="transactionManager" />
<property name="databaseSchemaUpdate" value="true" />
<property name="jobExecutorActivate" value="false" />
<property name="historyEventHandler" ref="camundaHistoryEventHandler"/>
</bean>


<bean id="camundaHistoryEventHandler" class="org.att.wellsfargo.CamundaHistoryEventHandler"></bean>

But i think control is not coming to handleEvent or Handleevents method when starting a service

Could you please let me know about this.

Thanks
Kumar

[Philipp Ossler]

Hi Kumar,

a simple custom history event handler can look like this:

// extend the default history event handler to create log entries additionally
public class CustomHistoryEventHandler extends DbHistoryEventHandler implements HistoryEventHandler {

  // protected final static Logger LOGGER = ...

  @Override

  public void handleEvent(HistoryEvent historyEvent) {

    // create db entry

    super.handleEvent(historyEvent);

    // create log entry
    LOGGER.log(historyEvent);

  }

}

You have to register the history event handler in your configuration:

<bean id="processEngineConfiguration" class="org.camunda.bpm.engine.impl.cfg.StandaloneProcessEngineConfiguration">

    <!-- ... -->
    <property name="history" value="audit" />  

    <property name="historyEventHandler" ref="customHistoryEventHandler" />

</bean>

When you execute a process instance then a db entry and a log entry should be created. Make sure that you set the history level in you configuration.

Greetings,

Philipp

[bharat...@gmail.com]

Thanks Philipp for providing this information and i able to generate logs using eventHandlers.

Thanks,
Bharath