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Drools dynamically add, modify, and delete rules

2022-07-02 12:14:00 【huan_ one thousand nine hundred and ninety-three】

List of articles

1、 background

In previous chapters , our drools The rule files are all in src/main/resources The directory says dead , This is not flexible enough . Suppose I want to run the program , Dynamically modify rules , This is not easy to achieve . Here we save the rule file to the database , Realize the dynamic loading of rules 、 Refresh .

2、 Pre knowledge

1、 How to dynamically build a kmodule.xml file

Dynamically build a kmodule.xml

2、kmodule.xml Who should load it 

KieFileSystem kieFileSystem = kieServices.newKieFileSystem();
kieFileSystem.writeKModuleXML(kieModuleModel.toXML());

3、 We drl How to load rule content 

kieFileSystem.write("src/main/resources/rules/rule01/1.drl","drl The content of the rules ");
KieBuilder kieBuilder = kieServices.newKieBuilder(kieFileSystem);
kieBuilder.buildAll();
Results results = kieBuilder.getResults();
List<Message> messages = results.getMessages(Message.Level.ERROR);
if(null != messages && !messages.isEmpty()){
    
    for (Message message : messages) {
    
        System.out.println(message);
    }
}

Be careful ：
From here we can see ,drl The content of the rules Be being kieFileSystem Loaded , Later, if we want to realize Dynamically update the rule content , that kieFileSystem Whether it should be the same , That is, we need to cache this kieFileSystem.
What are the consequences of not caching ？
When we load a new rule content , Then the previous rule content may be lost .

You can see , The path we write is src/main/resources/rules/rule01/1.drl That's true , So what does that mean ？ The simple understanding is as follows ：
src/main/resources： This can be understood as a fixed writing .
rules/rule01： This needs to see 1、 How to dynamically build a kmodule.xml file , There is a dynamic build kieBase01, Then add package yes rules/rule01. That is, it needs to be corresponding .
1.drl： The name of the rule file .

KieFileSystem： This is a virtual file system , Does not actually create files on disk , It's memory based .

4、 Build dynamically KieContainer

if (null == kieContainer) {
    
  kieContainer = kieServices.newKieContainer(kieServices.getRepository().getDefaultReleaseId());
}
//  to update 
((KieContainerImpl) kieContainer).updateToKieModule((InternalKieModule) kieBuilder.getKieModule());

The question here ？
1、kieContainer Can we create one each time , Then cover the old one with the new one ？

Personally, I don't think so , because , Cover , Means , We need to destroy the old KieContainer object , call kieContainer.dispose(), So if this time , We have created in our system KieSession, Processing rules , Then there will be problems .

2、kieServices.newKieContainer(ReleaseId) Medium ReleaseId How to get ？
ReleaseId Acquisition
The figure above illustrates ReleaseId How to get , Here we simply use the direct through kieServices.getRepository().getDefaultReleaseId() Get it .

3、updateToKieModule The role of
New KieModule Apply to existing KieContainer On the object , If KieSession The correspondence already exists , So the new rules are right KieSession Is visible .
** such as ：** We modified the content of the rule , that KieSession Yes, I know. .

3、 demand

  1. The contents of rules need to be dynamically loaded from the database , In the example, it is stored in memory .
  2. More than one... Needs to be created KieBase, Implement rule isolation .
  3. You can dynamically update or add rules .
  4. You can delete rules .

4、 Realization

1、 introduce jar package 

<dependencyManagement>
   <dependencies>
        <dependency>
            <groupId>org.drools</groupId>
            <artifactId>drools-bom</artifactId>
            <type>pom</type>
            <version>7.69.0.Final</version>
            <scope>import</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-dependencies</artifactId>
            <version>2.6.7</version>
            <scope>import</scope>
            <type>pom</type>
        </dependency>
    </dependencies>
</dependencyManagement>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.drools</groupId>
        <artifactId>drools-compiler</artifactId>
    </dependency>
    <dependency>
        <groupId>org.drools</groupId>
        <artifactId>drools-mvel</artifactId>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.22</version>
    </dependency>
</dependencies>

2、 Create a rule entity class

This entity class corresponds to the tables in the database one by one .

package com.huan.drools.entity;

import lombok.Getter;
import lombok.Setter;

import java.util.Date;

/** * drools  Rule entity class  * * @author huan.fu * @date 2022/5/27 - 10:00 */
@Getter
@Setter
public class DroolsRule {
    

    /** *  The rules id */
    private Long ruleId;
    /** * kbase Name  */
    private String kieBaseName;
    /** *  Set the kbase You need to load files from that directory , This is a virtual directory , be relative to  `src/main/resources` *  such as ：kiePackageName=rules/rule01  Then the current rule file write path is ： kieFileSystem.write("src/main/resources/rules/rule01/1.drl") */
    private String kiePackageName;
    /** *  The content of the rules  */
    private String ruleContent;
    /** *  Rule creation time  */
    private Date createdTime;
    /** *  Rule update time  */
    private Date updateTime;

    public void validate() {
    
        if (this.ruleId == null || isBlank(kieBaseName) || isBlank(kiePackageName) || isBlank(ruleContent)) {
    
            throw new RuntimeException(" There is a problem with the parameters ");
        }
    }

    private boolean isBlank(String str) {
    
        return str == null || str.isEmpty();
    }
}

Properties that need attention ：
kieBaseName: Created kbase Name .
kiePackageName： The kbase Properties of package Value .

3、 Realization drools Dynamic rules 

package com.huan.drools;

import com.huan.drools.entity.DroolsRule;
import lombok.extern.slf4j.Slf4j;
import org.drools.compiler.kie.builder.impl.InternalKieModule;
import org.drools.compiler.kie.builder.impl.KieContainerImpl;
import org.kie.api.KieBase;
import org.kie.api.KieServices;
import org.kie.api.builder.KieBuilder;
import org.kie.api.builder.KieFileSystem;
import org.kie.api.builder.Message;
import org.kie.api.builder.Results;
import org.kie.api.builder.model.KieBaseModel;
import org.kie.api.builder.model.KieModuleModel;
import org.kie.api.runtime.KieContainer;
import org.kie.api.runtime.KieSession;
import org.springframework.stereotype.Component;

import java.util.Collection;
import java.util.List;

/** * drools  management  * * @author huan.fu * @date 2022/5/27 - 14:42 */
@Component
@Slf4j
public class DroolsManager {
    

    //  This class itself is a singleton 
    private final KieServices kieServices = KieServices.get();
    // kie file system , Cache required , If every time you add a rule, you re new One word , There may be problems . That is, the rules previously added to the file system are gone 
    private final KieFileSystem kieFileSystem = kieServices.newKieFileSystem();
    //  It can be understood as building  kmodule.xml
    private final KieModuleModel kieModuleModel = kieServices.newKieModuleModel();
    //  The global unique one is required , If you create a new rule every time you add one , So the old one needs to be destroyed kieContainer, If there is one in use at this time KieSession, There may be a problem 
    private KieContainer kieContainer;

    /** *  Judge that kbase Whether there is  */
    public boolean existsKieBase(String kieBaseName) {
    
        if (null == kieContainer) {
    
            return false;
        }
        Collection<String> kieBaseNames = kieContainer.getKieBaseNames();
        if (kieBaseNames.contains(kieBaseName)) {
    
            return true;
        }
        log.info(" Need to create KieBase:{}", kieBaseName);
        return false;
    }

    public void deleteDroolsRule(String kieBaseName, String packageName, String ruleName) {
    
        if (existsKieBase(kieBaseName)) {
    
            KieBase kieBase = kieContainer.getKieBase(kieBaseName);
            kieBase.removeRule(packageName, ruleName);
            log.info(" Delete kieBase:[{}] package :[{}] The rules under :[{}]", kieBaseName, packageName, ruleName);
        }
    }

    /** *  Add or update  drools  The rules  */
    public void addOrUpdateRule(DroolsRule droolsRule) {
    
        //  obtain kbase The name of 
        String kieBaseName = droolsRule.getKieBaseName();
        //  Judge that kbase Whether there is 
        boolean existsKieBase = existsKieBase(kieBaseName);
        //  This object corresponds to kmodule.xml Medium kbase label 
        KieBaseModel kieBaseModel = null;
        if (!existsKieBase) {
    
            //  Create a kbase
            kieBaseModel = kieModuleModel.newKieBaseModel(kieBaseName);
            //  Not by default kieBase
            kieBaseModel.setDefault(false);
            //  Set the KieBase Package path to be loaded 
            kieBaseModel.addPackage(droolsRule.getKiePackageName());
            //  Set up kieSession
            kieBaseModel.newKieSessionModel(kieBaseName + "-session")
                    //  Not by default session
                    .setDefault(false);
        } else {
    
            //  Get the existing kbase object 
            kieBaseModel = kieModuleModel.getKieBaseModels().get(kieBaseName);
            //  Get packages
            List<String> packages = kieBaseModel.getPackages();
            if (!packages.contains(droolsRule.getKiePackageName())) {
    
                kieBaseModel.addPackage(droolsRule.getKiePackageName());
                log.info("kieBase:{} Add a new package :{}", kieBaseName, droolsRule.getKiePackageName());
            } else {
    
                kieBaseModel = null;
            }
        }
        String file = "src/main/resources/" + droolsRule.getKiePackageName() + "/" + droolsRule.getRuleId() + ".drl";
        log.info(" Load the virtual rule file :{}", file);
        kieFileSystem.write(file, droolsRule.getRuleContent());

        if (kieBaseModel != null) {
    
            String kmoduleXml = kieModuleModel.toXML();
            log.info(" load kmodule.xml:[\n{}]", kmoduleXml);
            kieFileSystem.writeKModuleXML(kmoduleXml);
        }

        KieBuilder kieBuilder = kieServices.newKieBuilder(kieFileSystem);
        //  adopt KieBuilder structure KieModule All of them KieBase
        kieBuilder.buildAll();
        //  Get the results of the build process 
        Results results = kieBuilder.getResults();
        //  Get error messages 
        List<Message> messages = results.getMessages(Message.Level.ERROR);
        if (null != messages && !messages.isEmpty()) {
    
            for (Message message : messages) {
    
                log.error(message.getText());
            }
            throw new RuntimeException(" Exception occurred while loading rules ");
        }
        // KieContainer Only the first time you need to create , Then you use this 
        if (null == kieContainer) {
    
            kieContainer = kieServices.newKieContainer(kieServices.getRepository().getDefaultReleaseId());
        } else {
    
            //  Realize dynamic update 
            ((KieContainerImpl) kieContainer).updateToKieModule((InternalKieModule) kieBuilder.getKieModule());
        }
    }

    /** *  Trigger rule , Here is a simple simulation , A... Will be inserted into the rule Integer Type value  */
    public String fireRule(String kieBaseName, Integer param) {
    
        //  establish kieSession
        KieSession kieSession = kieContainer.newKieSession(kieBaseName + "-session");
        StringBuilder resultInfo = new StringBuilder();
        kieSession.setGlobal("resultInfo", resultInfo);
        kieSession.insert(param);
        kieSession.fireAllRules();
        kieSession.dispose();
        return resultInfo.toString();
    }
}

It should be noted that ：

  1. KieFileSystem Need to be a singleton , That is, the same .
  2. KieContainer Need to be a singleton , That is, the same .
  3. adopt updateToKieModule Method dynamic update .

4、 Analog database , Implementation rule CRUD

package com.huan.drools.service.com;

import com.huan.drools.DroolsManager;
import com.huan.drools.entity.DroolsRule;
import com.huan.drools.service.DroolsRuleService;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.*;

/** * @author huan.fu * @date 2022/5/27 - 14:34 */
@Service
public class DroolsRuleServiceImpl implements DroolsRuleService {
    

    @Resource
    private DroolsManager droolsManager;

    /** *  Analog database  */
    private Map<Long, DroolsRule> droolsRuleMap = new HashMap<>(16);

    @Override
    public List<DroolsRule> findAll() {
    
        return new ArrayList<>(droolsRuleMap.values());
    }

    @Override
    public void addDroolsRule(DroolsRule droolsRule) {
    
        droolsRule.validate();
        droolsRule.setCreatedTime(new Date());
        droolsRuleMap.put(droolsRule.getRuleId(), droolsRule);
        droolsManager.addOrUpdateRule(droolsRule);
    }

    @Override
    public void updateDroolsRule(DroolsRule droolsRule) {
    
        droolsRule.validate();
        droolsRule.setUpdateTime(new Date());
        droolsRuleMap.put(droolsRule.getRuleId(), droolsRule);
        droolsManager.addOrUpdateRule(droolsRule);
    }

    @Override
    public void deleteDroolsRule(Long ruleId, String ruleName) {
    
        DroolsRule droolsRule = droolsRuleMap.get(ruleId);
        if (null != droolsRule) {
    
            droolsRuleMap.remove(ruleId);
            droolsManager.deleteDroolsRule(droolsRule.getKieBaseName(), droolsRule.getKiePackageName(), ruleName);
        }
    }
}

Here is the memory saving rule , It can also be saved to a database .

5、 Create a control layer 

@RestController
@RequestMapping("/drools/rule")
public class DroolsRuleController {
    

    @Resource
    private DroolsRuleService droolsRuleService;
    @Resource
    private DroolsManager droolsManager;

    @GetMapping("findAll")
    public List<DroolsRule> findAll() {
    
        return droolsRuleService.findAll();
    }

    @PostMapping("add")
    public String addRule(@RequestBody DroolsRule droolsRule) {
    
        droolsRuleService.addDroolsRule(droolsRule);
        return " Add success ";
    }

    @PostMapping("update")
    public String updateRule(@RequestBody DroolsRule droolsRule) {
    
        droolsRuleService.updateDroolsRule(droolsRule);
        return " Modification successful ";
    }

    @PostMapping("deleteRule")
    public String deleteRule(Long ruleId, String ruleName) {
    
        droolsRuleService.deleteDroolsRule(ruleId, ruleName);
        return " Delete successful ";
    }

    @GetMapping("fireRule")
    public String fireRule(String kieBaseName, Integer param) {
    
        return droolsManager.fireRule(kieBaseName, param);
    }
}

6、 Dynamic addition of test rules

1、 Add rules 

curl --location --request POST 'http://localhost:8080/drools/rule/add' \
--header 'User-Agent: apifox/1.0.0 (https://www.apifox.cn)' \
--header 'Content-Type: application/json' \
--data-raw '{ "ruleId": 1, "kieBaseName": "kieBase01", "kiePackageName": "rules.rule01", "ruleContent": "package rules.rule01 \n global java.lang.StringBuilder resultInfo \n rule \"rule-01\" when $i: Integer() then resultInfo.append(drools.getRule().getPackageName()).append(\".\").append(drools.getRule().getName()).append(\" Yes , Parameters passed by the front end :\").append($i); end" }'

package rules.rule01

global java.lang.StringBuilder resultInfo

rule "rule-01"
    when
        $i: Integer()
    then
        resultInfo.append(drools.getRule().getPackageName()).append(".").append(drools.getRule().getName()).append(" Yes , Parameters passed by the front end :").append($i);
end

2、 function 

*  ~ curl http://localhost:8080/drools/rule/fireRule\?kieBaseName\=kieBase01\&param\=1
rules.rule01.rule-01 Yes , Parameters passed by the front end :1%
*  ~

You can see that our dynamically loaded rules are executed .

7、 Modify rules

demand ： stay 6、 Dynamic addition of test rules On the basis of , Modify rules .

The previous rules 

package rules.rule01

global java.lang.StringBuilder resultInfo

rule "rule-01"
    when
        $i: Integer()
    then
        resultInfo.append(drools.getRule().getPackageName()).append(".").append(drools.getRule().getName()).append(" Yes , Parameters passed by the front end :").append($i);
end

Revised rules 

package rules.rule01

global java.lang.StringBuilder resultInfo

rule "rule-01"
    when
        $i: Integer(intValue() > 3) //  Notice here that 
    then
        resultInfo.append(drools.getRule().getPackageName()).append(".").append(drools.getRule().getName()).append(" Yes , Parameters passed by the front end :").append($i);
end

You can see that the changes are $i: Integer(intValue() > 3), That is, a conditional judgment is added .

1、 Modify rules 

*  ~ curl --location --request POST 'http://localhost:8080/drools/rule/update' \
--header 'User-Agent: apifox/1.0.0 (https://www.apifox.cn)' \
--header 'Content-Type: application/json' \
--data-raw '{ "ruleId": 1, "kieBaseName": "kieBase01", "kiePackageName": "rules.rule01", "ruleContent": "package rules.rule01 \n global java.lang.StringBuilder resultInfo \n rule \"rule-01\" when $i: Integer(intValue() > 3) then resultInfo.append(drools.getRule().getPackageName()).append(\".\").append(drools.getRule().getName()).append(\" Yes , Parameters passed by the front end :\").append($i); end" }'

The rule memory is modified here Integer The value must be >3 Execution only .

2、 function 

*  ~ curl http://localhost:8080/drools/rule/fireRule\?kieBaseName\=kieBase01\&param\=1
*  ~ curl http://localhost:8080/drools/rule/fireRule\?kieBaseName\=kieBase01\&param\=6
rules.rule01.rule-01 Yes , Parameters passed by the front end :6%
*  ~

You can see from above , When we deliver param=1 when , No result data , When param=6 Results are output from time to time .

8、 Delete

demand ： Delete the rule created in the previous step

1、 Deletion rule 

*  ~ curl --location --request POST 'http://localhost:8080/drools/rule/deleteRule?ruleId=1&ruleName=rule-01'

 Delete successful %
*  ~

2、 Running results 

*  ~ curl http://localhost:8080/drools/rule/fireRule\?kieBaseName\=kieBase01\&param\=6
*  ~ curl http://localhost:8080/drools/rule/fireRule\?kieBaseName\=kieBase01\&param\=1
*  ~

You can see that the deletion succeeded .

9、 simulation 2 individual kbase

1、 Add rules and execute 

*  ~ curl --location --request POST 'http://localhost:8080/drools/rule/add' \
--header 'Content-Type: application/json' \
--data-raw '{ "ruleId": 1, "kieBaseName": "kieBase01", "kiePackageName": "rules.rule01", "ruleContent": "package rules.rule01 \n global java.lang.StringBuilder resultInfo \n rule \"rule-01\" when $i: Integer() then resultInfo.append(drools.getRule().getPackageName()).append(\".\").append(drools.getRule().getName()).append(\" Yes , Parameters passed by the front end :\").append($i); end" }'
 Add success %
*  ~ curl --location --request POST 'http://localhost:8080/drools/rule/add' \
--header 'Content-Type: application/json' \
--data-raw '{ "ruleId": 2, "kieBaseName": "kieBase02", "kiePackageName": "rules.rule02", "ruleContent": "package rules.rule02 \n global java.lang.StringBuilder resultInfo \n rule \"rule-01\" when $i: Integer() then resultInfo.append(drools.getRule().getPackageName()).append(\".\").append(drools.getRule().getName()).append(\" Yes , Parameters passed by the front end :\").append($i); end" }'
 Add success %
*  ~ curl http://localhost:8080/drools/rule/fireRule\?kieBaseName\=kieBase01\&param\=1
rules.rule01.rule-01 Yes , Parameters passed by the front end :1%
*  ~ curl http://localhost:8080/drools/rule/fireRule\?kieBaseName\=kieBase02\&param\=1
rules.rule02.rule-01 Yes , Parameters passed by the front end :1%
*  ~

2、 perform

Insert picture description here

5、 Complete code

https://gitee.com/huan1993/spring-cloud-parent/tree/master/drools/drools-dynamic-crud-rule

6、 Reference documents

1、https://docs.drools.org/7.69.0.Final/drools-docs/html_single/index.html#_definingakiemoduleprogrammatically

原网站

版权声明
本文为[huan_ one thousand nine hundred and ninety-three]所创，转载请带上原文链接，感谢
https://yzsam.com/2022/183/202207020908546016.html

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