Menggunakan Camunda untuk orkestrasi yang nyaman berdasarkan REST dan Workflow Engine (tanpa Java)

Halo, Habr! Saya sajikan untuk perhatian Anda terjemahan artikel "Gunakan Camunda sebagai mesin orkestrasi dan alur kerja berbasis REST yang mudah digunakan (tanpa menyentuh Jawa)" oleh Bernd Rücker.

07.07.2020, terjemahan artikel oleh Bernd Rücker

, Java: C#, Node.JS/JavaScript Golang. , , -, Saga .

BPM- Camunda . — . , , «» Camunda Java-. , Java. ?

! , Camunda - Java , . :

• ;
• REST API;
• , Java;
• C # Node.JS;
• Camunda (Docker Tomcat).

Camunda Java Java (JVM). Camunda REST API, , , REST Camunda:

Camunda BPMN, XML-. Camunda Modeler.

Camunda Docker

Camunda — Docker. Camunda .

:

  docker run -d -p 8080:8080 camunda/camunda-bpm-platform:latest

Linux, Java Tomcats. Dockerfiles (, ) Github.

Camunda Enterprise Edition, Dockerfile.

Camunda Docker : Tomcat, . - , Docker- Tomcat, , , .

, Saga , . BPMN :

REST API . , trip.bpmn Camunda Docker, localhost: 8080:

  curl -w "\n" \
-H "Accept: application/json" \
-F "deployment-name=trip" \
-F "enable-duplicate-filtering=true" \
-F "deploy-changed-only=true" \
-F "trip.bpmn=@trip.bpmn" \
http://localhost:8080/engine-rest/deployment/creat

REST API , :

  curl \
-H "Content-Type: application/json" \
-X POST \
-d '{"variables":{"someData" : {"value" : "someValue", "type": "String"}},"businessKey" : "12345"}}' \
http://localhost:8080/engine-rest/<!-- -->process-definition/key/<!-- -->FlowingTripBookingSaga<!-- -->/start

: Camunda , ? Camunda (Push-Principle), , . worker REST, Camunda (Pull-Principle).

, fetchAndLock ( worker ):

  curl \
-H "Content-Type: application/json" \
-X POST \
-d <!-- -->'{"workerId":"worker123","maxTasks":1,"usePriority":true,"topics":[{"topicName": "reserve-car"}, "lockDuration": 10000, "variables": ["someData"]}]}'<!-- --> \
http://localhost:8080/engine-rest/external-task/fetchAndLock

Camunda, worker ( , external task, ):

  curl \
-H "Content-Type: application/json" \
-X POST \
-d <!-- -->'{"workerId":"worker123", "variables": {}}'<!-- --> \
http://localhost:8080/engine-rest/<!-- -->external-task/EXTERNAL_TASK_ID/complete

— Java, ? !

REST API . JavaScript JQuery, C# — System.Net.Http Newtonsoft.Json. . - .

:

• JavaScript: . Camunda;
• Java: . Camunda;
• C#: . , ;
• PHP: — API , , .

JavaScript Java, Camunda. , REST API Camunda. , , , REST API Camunda. .

C#

, :

  var camunda = new CamundaEngineClient("http://localhost:8080/engine-rest/engine/default/", null, null);
  // Deploy the BPMN XML file from the resources
  camunda.RepositoryService.Deploy("trip-booking", new List<object> {
        FileParameter.FromManifestResource(Assembly.GetExecutingAssembly(), "FlowingTripBookingSaga.Models.FlowingTripBookingSaga.bpmn")
     });
  
  // Register workers
  registerWorker("reserve-car", externalTask => {
    // here you can do the real thing! Like a sysout :-)
    Console.WriteLine("Reserving car now...");
    camunda.ExternalTaskService.Complete(workerId, externalTask.Id);
  });
  registerWorker("cancel-car", externalTask => {
    Console.WriteLine("Cancelling car now...");
    camunda.ExternalTaskService.Complete(workerId, externalTask.Id);
  });
  registerWorker("book-hotel", externalTask => {
    Console.WriteLine("Reserving hotel now...");
    camunda.ExternalTaskService.Complete(workerId, externalTask.Id);
  });
  // Register more workers...
  
  StartPolling();
  
  string processInstanceId = camunda.BpmnWorkflowService.StartProcessInstance("FlowingTripBookingSaga", new Dictionary<string, object>()
    {
      {"someBookingData", "..." }
    });

: . .

Node.js

  var Workers = require('camunda-worker-node');
  var workers = Workers('http://localhost:8080/engine-rest', {
    workerId: 'some-worker-id'
  });
  
  workers.registerWorker('reserve-car', [ 'someData' ], function(context, callback) {
    var someNewData = context.variables.someData + " - added something";
    callback(null, {
      variables: {
        someNewData: someNewData
      }
    });
  });
  
  workers.shutdown();

github.com

Camunda

Docker «Camunda standalone WAR»

Docker Camunda Tomcat (, Docker Tomcat), Camunda WAR-.

Java, Camunda Standalone war. Maven : Maven war Maven Overlay.

Camunda Tomcat

— Camunda Tomcat, . Java Runtime Environment (JRE), . .

- , Tomcat, . , Tomcat , . Google , .

Camunda Tomcat

— Tomcat Camunda, . Tomcat, , , , Windows.

Camunda

, - Camunda. Camunda , , — : REST API . , .

Seperti yang mungkin telah Anda perhatikan, memulai dengan Camunda sangat mudah, terlepas dari bahasa yang Anda gunakan. Poin kuncinya adalah bahwa semua komunikasi dilakukan melalui API REST. Instalasi juga cukup mudah, terutama saat menggunakan Docker.