How to access DRL files outside of the classpath?

[Johnny Swarthout]

Hello,

 

We have been working on moving from drools version 5.3.1 to 7.0.0. As well as moving from guvnor to kie workbench.

Before making this move we have been storing our DRL file outside of our Rule Engine project classpath and it has been working great.

When we tried to do this with version 7.0.0, our Rules Engine project could not find our DRL's. When moving the DRLs into the classpath

it can find the rules and they fire like they are supposed to. Is there a way that we could store the DRL files outside

of the classpath and still have our Rules Engine project find them? We would like to keep the DRL files off the classpath as this may

cause frequent code deployments. Plus it is much easier to see and update the DRL files when they are stored on a local path.

 

For reference, we are using eclipse neon 3, jdk8, and JBoss EAP 7.0 server.

 

Thanks,

Johnny

[Pavan Nannapaneni]

Hi Johnny,

You can fetch the rules remotely using your application by downloading the JAR file of the rules from Drools Workbench and include it's contents into class-path. To be able to do this, you need to add the artifact as a KieModule into your application's KieRepository. The "source" of the KieModule will come from the data contained in the downloaded rule artifact which is declared as a org.drools.core.io.impl.UrlResource. if you are using spring, below here is the sample code. You can use kieScanner to get the latest version of rules from workbench without redeploying.

@Bean

public KieContainer kieContainer() throws IOException {

    KieServices ks = KieServices.Factory.get();

    KieResources resources = ks.getResources();

    String url = "http://localhost:8080/drools-wb/maven2/package/xxxx/version/xxxx.jar";

    UrlResource urlResource = (UrlResource) resources.newUrlResource(url);

    urlResource.setUsername("drools-user");

    urlResource.setPassword("password");

    urlResource.setBasicAuthentication("enabled");

    InputStream stream = urlResource.getInputStream();

    KieRepository repo = ks.getRepository();

    KieModule k = repo.addKieModule(resources.newInputStreamResource(stream));

    return ks.newKieContainer(k.getReleaseId());

}

-Pavan

[Johnny Swarthout]

Thank you.

[Abhijit Humbe]

There is one more approach available to access rules those are not available in classpath:

 KieServices kServices = KieServices.Factory.get();

KieFileSystem kfs = kServices.newKieFileSystem();
KieRepository kr = kServices.getRepository();
file = new File("/NotBackedUp/Download/SampleRules/Sample.drl");
resource = kServices.getResources().newFileSystemResource(file).setResourceType(ResourceType.DRL);
kfs.write(resource);

file = new File("/NotBackedUp/Download/SampleRules/Sample2.drl");
resource = kServices.getResources().newFileSystemResource(file).setResourceType(ResourceType.DRL);
kfs.write(resource);

KieBuilder kb = kServices.newKieBuilder(kfs);
kb.buildAll();
KieContainer kContainer = kServices.newKieContainer(kr.getDefaultReleaseId());
KieSession kSession = kContainer.newKieSession();

With this approach you will be able to load rules those are not in classpath but available somewhere in filesystem

Hope this helps.

Abhijit Humbe

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[Johnny Swarthout]

This is very similar to the approach we ended up taking.  So yes, good solution.  Thank you.

Abhijit Humbe

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[shashank patel]

Hi,

 In which class  i  should make  changes and  after   building  the    jar(Which   jar)  how  i  should  proceed.

I am  new to  drools .

Can anybody  help  me  on this.

Becoz  it  is urgent.