Chapter 14. Logging

The logging mechanism allows you to store information about the execution of a process instance. It is provided by a special event listener that listens to the Process Engine for any relevant events to be logged, so that the information can be stored separately from other non-log information stored either in the server built-in database (h2) or a connected data source using JPA or Hibernate.
The jbpm-audit module provides the event listener and also allows you to store process-related information directly in a database using JPA or Hibernate. The data of the following entities is stored as follows:
  • Process instance as processinstancelog
  • Element instance as nodeinstancelog
  • Variable instance as variableinstancelog

Table 14.1. Fields of the ProcessInstanceLog table

Field Description Nullable
id
The primary key of the log entity
No
end_date
The end date of the process instance
Yes
processid
The name (id) of the underlying process
Yes
processinstanceid
The id of the process instance
No
start_date
The start date of the process instance
Yes
status
The status of the process instance
Yes
parentProcessInstanceId
The process instance id of the parent process instance if applicable
Yes
outcome
The outcome of the process instance (details on the process finish, such as error code)
Yes

Table 14.2. Fields of the NodeInstanceLog table

Field Description Nullable
id
The primary key of the log entity
No
log_date
The date of the event
Yes
nodeid
The node id of the underlying Process Element
Yes
nodeinstanceid
The id of the node instance
Yes
nodename
The name of the underlying node
Yes
processid
The id of the underlying process
Yes
processinstanceid
The id of the parent process instance
No
type
The type of the event (0 = enter event, 1 = exit event)
No

Table 14.3. Fields of the VariableInstanceLog table

Field Description Nullable
id
The primary key of the log entity
No
log_date
The date of the event
Yes
processid
The name (id) of the underlying process
Yes
processinstanceid
The id of the process instance
No
value
The value of the variable at log time
Yes
variableid
The variable id as defined in the process definition
Yes
variableinstanceid
The id of the variable instance
Yes
outcome
The outcome of the process instance (details on the process finish, such as error code)
Yes
If neccessary, define your own data model of custom information and use the process event listeners to extract the information.

14.1. Logging events to database

To log an event that occurs on runtime in a Process instance, an Element instance, or a variable instance, you need to do the following:
  1. Map the Log classes to the data source, so that the given data source accepts the log entries. On Red Hat JBoss EAP, edit the data source properties in the persistence.xml file.

    Example 14.1. The ProcessInstanceLog, NodeInstanceLog and VariableInstanceLog classes enabled for processInstanceDS

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<persistence  version="1.0"  xsi:schemaLocation=
    "http://java.sun.com/xml/ns/persistence
     http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd
     http://java.sun.com/xml/ns/persistence/orm
     http://java.sun.com/xml/ns/persistence/orm_1_0.xsd"
  xmlns:orm="http://java.sun.com/xml/ns/persistence/orm"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns="http://java.sun.com/xml/ns/persistence">

  <persistence-unit name="org.jbpm.persistence.jpa">
    <provider>org.hibernate.ejb.HibernatePersistence</provider>
    <jta-data-source>jdbc/processInstanceDS</jta-data-source>
    <class>org.drools.persistence.info.SessionInfo</class>
    <class>org.jbpm.persistence.processinstance.ProcessInstanceInfo</class>
    <class>org.drools.persistence.info.WorkItemInfo</class>
    <class>org.jbpm.process.audit.ProcessInstanceLog</class>
    <class>org.jbpm.process.audit.NodeInstanceLog</class>
    <class>org.jbpm.process.audit.VariableInstanceLog</class>

    <properties>
      <property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect"/>
      <property name="hibernate.max_fetch_depth" value="3"/>
      <property name="hibernate.hbm2ddl.auto" value="update"/>
      <property name="hibernate.show_sql" value="true"/>
      <property name="hibernate.transaction.manager_lookup_class"
                value="org.hibernate.transaction.BTMTransactionManagerLookup"/>
    </properties>
  </persistence-unit>
</persistence>
  2. Register a logger on your Kie Session.

    Example 14.2. Import the Loggers

    import org.jbpm.process.audit.AuditLogService;
import org.jbpm.process.audit.AuditLoggerFactory;
import org.jbpm.process.audit.AuditLoggerFactory.Type;
import org.jbpm.process.audit.JPAAuditLogService;
...

    Example 14.3. Registering a Logger to a Kie Session

    @PersistenceUnit(unitName = PERSISTENCE_UNIT_NAME)
  private EntityManagerFactory emf;

  private AuditLogService auditLogService;
@PostConstruct
  public void configure() {
  
  auditLogService = new JPAAuditLogService(emf);
  ((JPAAuditLogService) auditLogService).setPersistenceUnitName(PERSISTENCE_UNIT_NAME);
  
  if( emf == null ) { 
  ((JPAAuditLogService) auditLogService).setPersistenceUnitName(PERSISTENCE_UNIT_NAME);
  }
  
  RuntimeEngine runtime = singletonManager.getRuntimeEngine(EmptyContext.get());
  KieSession ksession = runtime.getKieSession();
  AuditLoggerFactory.newInstance(Type.JPA, ksession, null);

  }
  3. Optionally, call the method addFilter on the logger to filter out irrelevant information. Only information accepted by all filters appears in the database.
  4. Logger classes can be viewed in the Audit View: 
    <dependency>
	<groupId>org.jbpm</groupId>
	<artifactId>jbpm-audit</artifactId>
	<version>6.0.1.Final</version>
</dependency>