executor-pool/pom.xml

@@ -63,6 +63,12 @@
             <artifactId>javax.transaction-api</artifactId>
             <scope>compile</scope>
         </dependency>
+        <dependency>
+            <groupId>org.eclipse.paho</groupId>
+            <artifactId>org.eclipse.paho.client.mqttv3</artifactId>
+            <version>1.2.5</version>
+            <scope>compile</scope>
+        </dependency>
     </dependencies>
 
 	<build>

executor-pool/src/main/java/ch/unisg/common/ConfigProperties.java

@@ -0,0 +1,23 @@
+package ch.unisg.common;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.env.Environment;
+import org.springframework.stereotype.Component;
+
+import java.net.URI;
+
+@Component
+public class ConfigProperties {
+    @Autowired
+    private Environment environment;
+
+    /**
+     * Retrieves the URI of the WebSub hub. In this project, we use a single WebSub hub, but we could
+     * use multiple.
+     *
+     * @return the URI of the WebSub hub
+     */
+    public URI getMqttBrokerUri() {
+        return URI.create(environment.getProperty("mqtt.broker.uri"));
+    }
+}

executor-pool/src/main/java/ch/unisg/executorpool/TestController.java

@@ -1,12 +0,0 @@
-package ch.unisg.executorpool;
-
-import org.springframework.web.bind.annotation.RequestMapping;
-import org.springframework.web.bind.annotation.RestController;
-
-@RestController
-public class TestController {
-    @RequestMapping("/")
-    public String index() {
-        return "Hello World! Executor Pool";
-    }
-}

executor-pool/src/main/java/ch/unisg/executorpool/adapter/common/clients/TapasMqttClient.java

@@ -0,0 +1,41 @@
+package ch.unisg.executorpool.adapter.common.clients;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.eclipse.paho.client.mqttv3.*;
+import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
+
+import java.nio.charset.StandardCharsets;
+import java.util.UUID;
+
+public class TapasMqttClient {
+    private static final Logger LOGGER = LogManager.getLogger(TapasMqttClient.class);
+
+    private static TapasMqttClient tapasClient = null;
+
+    private MqttClient mqttClient;
+    private final String mqttClientId;
+    private final String brokerAddress;
+
+    private TapasMqttClient(String brokerAddress) {
+        this.mqttClientId = UUID.randomUUID().toString();
+        this.brokerAddress = brokerAddress;
+    }
+
+    public static synchronized TapasMqttClient getInstance(String brokerAddress) {
+
+        if (tapasClient == null) {
+            tapasClient = new TapasMqttClient(brokerAddress);
+        }
+
+        return tapasClient;
+    }
+
+    public void publishMessage(String topic, String payload) throws MqttException {
+        mqttClient = new org.eclipse.paho.client.mqttv3.MqttClient(brokerAddress, mqttClientId, new MemoryPersistence());
+        mqttClient.connect();
+        MqttMessage message = new MqttMessage(payload.getBytes(StandardCharsets.UTF_8));
+        mqttClient.publish(topic, message);
+        mqttClient.disconnect();
+    }
+}

executor-pool/src/main/java/ch/unisg/executorpool/adapter/in/web/AddNewExecutorToExecutorPoolWebController.java

@@ -1,5 +1,6 @@
 package ch.unisg.executorpool.adapter.in.web;
 
+import ch.unisg.executorpool.adapter.common.clients.TapasMqttClient;
 import ch.unisg.executorpool.adapter.common.formats.ExecutorJsonRepresentation;
 import ch.unisg.executorpool.application.port.in.AddNewExecutorToExecutorPoolUseCase;
 import ch.unisg.executorpool.application.port.in.AddNewExecutorToExecutorPoolCommand;
@@ -13,6 +14,10 @@ import org.springframework.web.bind.annotation.RestController;
 import org.springframework.web.server.ResponseStatusException;
 import javax.validation.ConstraintViolationException;
 import java.net.URI;
+import java.nio.charset.StandardCharsets;
+import java.util.UUID;
+
+import org.eclipse.paho.client.mqttv3.*;
 
 @RestController
 public class AddNewExecutorToExecutorPoolWebController {
@@ -36,6 +41,7 @@ public class AddNewExecutorToExecutorPoolWebController {
             responseHeaders.add(HttpHeaders.CONTENT_TYPE, ExecutorJsonRepresentation.EXECUTOR_MEDIA_TYPE);
 
             return new ResponseEntity<>(ExecutorJsonRepresentation.serialize(newExecutor), responseHeaders, HttpStatus.CREATED);
+
         } catch (ConstraintViolationException e){
             throw new ResponseStatusException(HttpStatus.BAD_REQUEST, e.getMessage());
         }

executor-pool/src/main/java/ch/unisg/executorpool/adapter/out/messaging/PublishExecutorAddedEventAdapter.java

@@ -0,0 +1,43 @@
+package ch.unisg.executorpool.adapter.out.messaging;
+
+import ch.unisg.common.ConfigProperties;
+import ch.unisg.executorpool.adapter.common.clients.TapasMqttClient;
+import ch.unisg.executorpool.adapter.common.formats.ExecutorJsonRepresentation;
+import ch.unisg.executorpool.application.port.out.ExecutorAddedEventPort;
+import ch.unisg.executorpool.domain.ExecutorAddedEvent;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.eclipse.paho.client.mqttv3.MqttException;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Primary;
+import org.springframework.core.env.Environment;
+import org.springframework.stereotype.Component;
+
+import java.net.URI;
+
+@Component
+@Primary
+public class PublishExecutorAddedEventAdapter implements ExecutorAddedEventPort {
+
+    private static final Logger LOGGER = LogManager.getLogger(PublishExecutorAddedEventAdapter.class);
+
+    // TODO Can't autowire. Find fix
+    /*
+    @Autowired
+    private ConfigProperties config;
+    */
+
+    @Autowired
+    private Environment environment;
+
+    @Override
+    public void publishExecutorAddedEvent(ExecutorAddedEvent event){
+        try{
+            var mqttClient = TapasMqttClient.getInstance(environment.getProperty("mqtt.broker.uri"));
+            mqttClient.publishMessage("ch/unisg/tapas/executors/added", ExecutorJsonRepresentation.serialize(event.getExecutorClass()));
+        }
+        catch (MqttException e){
+            LOGGER.error(e.getMessage(), e);
+        }
+    }
+}

executor-pool/src/main/java/ch/unisg/executorpool/application/port/out/ExecutorAddedEventPort.java

@@ -0,0 +1,8 @@
+package ch.unisg.executorpool.application.port.out;
+
+import ch.unisg.executorpool.domain.ExecutorAddedEvent;
+import org.eclipse.paho.client.mqttv3.MqttException;
+
+public interface ExecutorAddedEventPort {
+    void publishExecutorAddedEvent(ExecutorAddedEvent event);
+}

executor-pool/src/main/java/ch/unisg/executorpool/application/service/AddNewExecutorToExecutorPoolService.java

@@ -2,24 +2,33 @@ package ch.unisg.executorpool.application.service;
 
 import ch.unisg.executorpool.application.port.in.AddNewExecutorToExecutorPoolUseCase;
 import ch.unisg.executorpool.application.port.in.AddNewExecutorToExecutorPoolCommand;
+import ch.unisg.executorpool.application.port.out.ExecutorAddedEventPort;
+import ch.unisg.executorpool.domain.ExecutorAddedEvent;
 import ch.unisg.executorpool.domain.ExecutorClass;
 import ch.unisg.executorpool.domain.ExecutorPool;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Component;
-import org.yaml.snakeyaml.constructor.DuplicateKeyException;
 
 import javax.transaction.Transactional;
-import javax.validation.ConstraintViolationException;
 
-@RequiredArgsConstructor
 @Component
 @Transactional
 public class AddNewExecutorToExecutorPoolService implements AddNewExecutorToExecutorPoolUseCase {
 
+    private final ExecutorAddedEventPort executorAddedEventPort;
+
+    public AddNewExecutorToExecutorPoolService(ExecutorAddedEventPort executorAddedEventPort){
+        this.executorAddedEventPort = executorAddedEventPort;
+    }
+
     @Override
     public ExecutorClass addNewExecutorToExecutorPool(AddNewExecutorToExecutorPoolCommand command){
         ExecutorPool executorPool = ExecutorPool.getExecutorPool();
+        var newExecutor = executorPool.addNewExecutor(command.getExecutorUri(), command.getExecutorTaskType());
 
-        return executorPool.addNewExecutor(command.getExecutorUri(), command.getExecutorTaskType());
+        var executorAddedEvent = new ExecutorAddedEvent(newExecutor);
+        executorAddedEventPort.publishExecutorAddedEvent(executorAddedEvent);
+
+        return newExecutor;
     }
 }

executor-pool/src/main/java/ch/unisg/executorpool/domain/ExecutorAddedEvent.java

@@ -0,0 +1,10 @@
+package ch.unisg.executorpool.domain;
+
+import lombok.Getter;
+
+public class ExecutorAddedEvent {
+    @Getter
+    private ExecutorClass executorClass;
+
+    public ExecutorAddedEvent(ExecutorClass executorClass) { this.executorClass = executorClass; }
+}

executor-pool/src/main/resources/application.properties

@@ -1 +1,3 @@
 server.port=8083
+
+mqtt.broker.uri=tcp://localhost:1883