कैमुंडा बाहरी कार्य - लचीला और स्केलेबल वास्तुकला के साथ अनुप्रयोगों के निर्माण के लिए एक शक्तिशाली उपकरण

1. जावा कोड के लिए एक तुल्यकालिक कॉल का उपयोग करना।
2. बाहरी कार्य बनाना।

बीपीएमएन में बाहरी कार्य

1. , «» , «».
2. camunda , , .
3. camunda (/).

1. एक नियमित कार्य बनाएँ ।
2. इसके प्रकार को सेवा कार्य में बदलें ।
3. बाहरी करने के लिए कार्यान्वयन सेट करें ।
4. विषय फ़ील्ड का मान निर्दिष्ट करें ।

बाहरी कार्य कर्मी

const baseUrl = 'http://localhost:8080/my-app/rest';
const workerSettings = {
 workerId: 'worker01', // some unique name for the current worker instance
 maxTasks: 5,
 topics: [
   {
     topicName: 'sendEmail',
     lockDuration: 10000, // How much time the worker thinks he needs to process the task
     variables: ['video'] // Which variables should be returned in the response (to avoid additional REST calls to read data)
   }]};
const requestParams = {method: 'POST', headers: {contentType: 'application/json'}};

function pollExternalTasks() {
 return fetch(`${baseUrl}/external-task/fetchAndLock`, {
   ...requestParams,
   body: JSON.stringify(workerSettings)
 })
}

function processExternalTask(result = []) {
 return Promise.all(result.map(externalTask => {
   sendEmail(externalTask); // Here the actual work would be done

   return fetch(`${baseUrl}/external-task/${externalTask.id}/complete`, {
     ...requestParams,
     body: JSON.stringify({workerId: workerSettings.workerId}),
   })
 }));
}

setInterval(() => {
 pollExternalTasks().then(processExternalTask)
}, 20000);

कैमंडा बाहरी कार्य क्लाइंट

public class App {
   public static void main(String... args) {
       // bootstrap the client
       ExternalTaskClient client = ExternalTaskClient.create()
           .baseUrl("http://localhost:8080/engine-rest")
           .asyncResponseTimeout(1000)
           .build();

       // subscribe to the topic
       client.subscribe("sendEmail").handler((externalTask, externalTaskService) -> {
           try {
               String result = sendEmail(externalTask)
               Map<String, Object> variables = new HashMap<>();

               variables.put("result", result);
               externalTaskService.complete(externalTask, variables);
               System.out.println("The External Task " + externalTask.getId() + " has been completed!");
           } catch (e: Exception) {
               externalTaskService.handleFailure(externalTask, e.message, e.stackTrace.toString())
           }
       }).open();
   }
}

@Service
class EmailWorker(
   private val runtimeService: RuntimeService
) {
   val builder = ExternalTaskClientBuilderImpl().baseUrl("http://localhost:8080").workerId("myWorker")
   val taskClient = builder.build()
   val engineClient = (builder as ExternalTaskClientBuilderImpl).engineClient

   @PostConstruct
   fun init() {
       taskClient
           .subscribe("sendEmail")
           .lockDuration(10000)
           .handler { externalTask, externalService ->
               runtimeService.startProcessInstanceByKey(
                   "SendEmailProcess",
                   externalTask.getVariable("emailId"),
                   mapOf(
                       "text" to externalTask.getVariable("text"),
                       "email" to externalTask.getVariable("email")
                   )
               )
           }
           .open()
   }


   @PreDestroy
   fun destroy() {
       taskClient.stop()
   }
}

// Delegate from SendEmailProcess process
@Component
class EmailResultDelegate(private val emailWorker: EmailWorker) {
   fun doExecute(execution: DelegateExecution) {
       emailWorker.engineClient.complete(
           execution.readVar(EXTERNAL_TASK_ID),
           mapOf("result" to "Success")
       )
   }
}

बाहरी कार्य के वास्तु लाभ