3.5. Using a KIE scanner to monitor and update KIE containers

Procedure

1. In the relevant .java class in your project, register and start the KIE scanner as shown in the following example code:

   Registering and starting a KIE scanner for a KIE container

   import org.kie.api.KieServices;
   import org.kie.api.builder.ReleaseId;
   import org.kie.api.runtime.KieContainer;
   import org.kie.api.builder.KieScanner;
   
   ...
   
   KieServices kieServices = KieServices.Factory.get();
   ReleaseId releaseId = kieServices
     .newReleaseId("com.sample", "my-app", "1.0-SNAPSHOT");
   KieContainer kContainer = kieServices.newKieContainer(releaseId);
   KieScanner kScanner = kieServices.newKieScanner(kContainer);
   
   // Start KIE scanner for polling the Maven repository every 10 seconds (10000 ms)
   kScanner.start(10000L);

   In this example, the KIE scanner is configured to run with a fixed time interval. The minimum KIE scanner polling interval is 1 millisecond (ms) and the maximum polling interval is the maximum value of the data type long. A polling interval of 0 or less results in a java.lang.IllegalArgumentException: pollingInterval must be positive error. You can also configure the KIE scanner to run on demand by invoking the scanNow() method.

   The project group ID, artifact ID, and version (GAV) settings in the example are defined as com.sample:my-app:1.0-SNAPSHOT. The project version must contain the -SNAPSHOT suffix to enable the KIE scanner to retrieve the latest build of the specified artifact version. If you change the snapshot project version number, such as increasing to 1.0.1-SNAPSHOT, then you must also update the version in the GAV definition in your KIE scanner configuration. The KIE scanner does not retrieve updates for projects with static versions, such as com.sample:my-app:1.0.

2. In the settings.xml file of your Maven repository, set the updatePolicy configuration to always to enable the KIE scanner to function properly:

   <profile>
     <id>guvnor-m2-repo</id>
     <repositories>
       <repository>
         <id>guvnor-m2-repo</id>
         <name>BA Repository</name>
         <url>http://localhost:8080/decision-central/maven2/</url>
         <layout>default</layout>
         <releases>
           <enabled>true</enabled>
           <updatePolicy>always</updatePolicy>
         </releases>
         <snapshots>
           <enabled>true</enabled>
           <updatePolicy>always</updatePolicy>
         </snapshots>
       </repository>
     </repositories>
   </profile>

   After the KIE scanner starts polling, if the KIE scanner detects an updated version of the SNAPSHOT project in the specified KIE container, the KIE scanner automatically downloads the new project version and triggers an incremental build of the new project. From that moment, all of the new KieBase and KieSession objects that were created from the KIE container use the new project version.

   For information about starting or stopping a KIE scanner using KIE Server APIs, see Interacting with Red Hat Decision Manager using KIE APIs.