7.4. History Log
7.4.1. History Log
The history logs store information about the execution of process instances, so that the information can be retrieved and viewed at a later time. History logs contain information, for instance, about the number of processes that have run and are running.
This history log of execution information is created based on events that the process engine generates during execution. This is possible because the jBPM runtime engine provides a generic mechanism to listen to events. The necessary information can easily be extracted from these events and then persisted to a database. Filters can also be used to limit the scope of the logged information.
7.4.2. The Business Activity Monitoring Data Model
The jbpm-bam module contains an event listener that stores process-related information in a database using JPA or Hibernate directly. The data model itself contains three entities: one for process instance information, one for node instance information, and one for (process) variable instance information.
Figure 7.2. Business Activity Monitoring data model
The
ProcessInstanceLog table contains the basic log information about a process instance.
| Field | Description | Nullable |
|---|---|---|
id | The primary key and ID of the log entity | NOT NULL |
end_date | When applicable, the end date of the process instance | |
processid | The name (ID) of the process | |
processinstanceid | The process instance ID | NOT NULL |
start_date | The start date of the process instance |
The
NodeInstanceLog table contains more information about which nodes were executed inside each process instance. Whenever a node instance is entered from one of its incoming connections or is exited through one of its outgoing connections, that information is stored in this table.
| Field | Description | Nullable |
|---|---|---|
id | The primary key and ID of the log entity | NOT NULL |
log_date | The date of the event | |
nodeid | The node ID of the corresponding node in the process definition | |
nodeinstanceid | The node instance ID | |
nodename | The name of the node | |
processid | The ID of the process that the process instance is executing | |
processinstanceid | The process instance ID | NOT NULL |
type | The type of the event (0 = enter, 1 = exit) | NOT NULL |
The
VariableInstanceLog table contains information about changes in variable instances. The default is to only generate log entries after a variable changes. It is also possible to log entries before the variable's value changes.
| Field | Description | Nullable |
|---|---|---|
id | The primary key and ID of the log entity | NOT NULL |
log_date | The date of the event | |
processid | The ID of the process that the process instance is executing | |
processinstanceid | The process instance ID | NOT NULL |
value | The value of the variable at the time that the log is made | |
variableid | The variable ID in the process definition | |
variableinstanceid | The ID of the variable instance |
7.4.3. Storing Process Events in a Database
To log process history in a database, register the logger to the session:
StatefulKnowledgeSession ksession = ...; JPAWorkingMemoryDbLogger logger = new JPAWorkingMemoryDbLogger(ksession); // invoke methods one your session here logger.dispose();
Note that this logger is like any other audit logger, and one or more filters can be added by calling the method
addFilter to ensure that only relevant information is stored in the database.
The Logger should be disposed of when it is no longer needed.
The persistence database is configured in the
persistence.xml file, which is located business-central-server.war/WEB-INF/classes/META-INF/ directory of the JBoss BRMS 5.3 deployable installation.
<?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="ProcessService">
<jta-data-source>java:/DefaultDS</jta-data-source>
<properties>
<property name="hibernate.hbm2ddl.auto" value="create-drop"/>
</properties>
</persistence-unit-->
<persistence-unit name="org.jbpm.persistence.jpa" transaction-type="JTA">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<jta-data-source>java:/DefaultDS</jta-data-source>
<mapping-file>META-INF/JBPMorm.xml</mapping-file>
<class>org.jbpm.persistence.processinstance.ProcessInstanceInfo</class>
<class>org.drools.persistence.info.SessionInfo</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.HSQLDialect"/>
<property name="hibernate.max_fetch_depth" value="3"/>
<property name="hibernate.hbm2ddl.auto" value="update" />
<property name="hibernate.show_sql" value="false" />
<property name="hibernate.transaction.manager_lookup_class" value="org.hibernate.transaction.JBossTransactionManagerLookup" />
</properties>
</persistence-unit>
</persistence>
