add: Monitor microservice

monitor/pom.xml

@@ -0,0 +1,85 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>3.2.0</version>
+        <relativePath/>
+    </parent>
+
+    <groupId>netwatch</groupId>
+    <artifactId>monitor</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>monitor</name>
+    <description>Microservice for Checking Services Health.</description>
+
+    <properties>
+        <java.version>21</java.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.amqp</groupId>
+            <artifactId>spring-rabbit-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-redis</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-amqp</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-webflux</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+            <version>5.10.1</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <version>5.3.1</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.json</groupId>
+            <artifactId>json</artifactId>
+            <version>20231013</version>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>1.18.30</version>
+            <scope>provided</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+                <configuration>
+                    <source>21</source>
+                    <target>21</target>
+                    <encoding>UTF-8</encoding>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

monitor/src/main/java/netwatch/monitor/MonitorApplication.java

@@ -0,0 +1,21 @@
+package netwatch.monitor;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+import org.springframework.scheduling.annotation.EnableScheduling;
+import org.springframework.web.client.RestTemplate;
+
+@EnableScheduling
+@SpringBootApplication
+public class MonitorApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(MonitorApplication.class, args);
+	}
+
+	@Bean
+    public RestTemplate restTemplate() {
+        return new RestTemplate();
+    }
+}

monitor/src/main/java/netwatch/monitor/config/RabbitMqConfig.java

@@ -0,0 +1,20 @@
+package netwatch.monitor.config;
+
+import org.springframework.amqp.core.FanoutExchange;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+// This class configures a Fanout Exchange for broadcasting messages to all bound queues.
+// @author Antonio Scardace
+// @version 1.0
+
+@Configuration
+public class RabbitMqConfig {
+
+    private static final String EXCHANGE_NAME = System.getenv("RABBITMQ_EXCHANGE");
+
+    @Bean
+    public FanoutExchange fanoutExchange() {
+        return new FanoutExchange(EXCHANGE_NAME);
+    }
+}

monitor/src/main/java/netwatch/monitor/config/RedisConfig.java

@@ -0,0 +1,46 @@
+package netwatch.monitor.config;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.redis.connection.RedisConnectionFactory;
+import org.springframework.data.redis.connection.RedisStandaloneConfiguration;
+import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
+import org.springframework.data.redis.core.RedisTemplate;
+import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
+import org.springframework.data.redis.serializer.StringRedisSerializer;
+
+import netwatch.monitor.entities.ObservationId;
+
+// Configuration class for connecting to Redis and for using RedisTemplate.
+// @author Antonio Scardace
+// @version 1.0
+
+@Configuration
+public class RedisConfig {
+
+    @Value("${spring.redis.host}")
+    private String redisHost;
+
+    @Value("${spring.redis.port}")
+    private int redisPort;
+
+    @Value("${spring.redis.password}")
+    private String redisPassword;
+
+    @Bean
+    public LettuceConnectionFactory redisConnectionFactory() {
+        RedisStandaloneConfiguration config = new RedisStandaloneConfiguration(redisHost, redisPort);
+        config.setPassword(redisPassword);
+        return new LettuceConnectionFactory(config);
+    }
+
+    @Bean
+    public RedisTemplate<String, ObservationId> redisTemplate(RedisConnectionFactory connectionFactory) {
+        RedisTemplate<String, ObservationId> redisTemplate = new RedisTemplate<>();
+        redisTemplate.setConnectionFactory(connectionFactory);
+        redisTemplate.setKeySerializer(new StringRedisSerializer());
+        redisTemplate.setValueSerializer(new Jackson2JsonRedisSerializer<>(ObservationId.class));
+        return redisTemplate;
+    }
+}

monitor/src/main/java/netwatch/monitor/entities/Contact.java

@@ -0,0 +1,21 @@
+package netwatch.monitor.entities;
+
+import java.io.Serializable;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+// This class represents the "contacts" entity in the database.
+// The Primary Key is the field "value".
+// @author Antonio Scardace
+// @version 1.0
+
+@NoArgsConstructor
+@AllArgsConstructor
+@Data
+public class Contact implements Serializable {
+
+    private String value;
+    private String type;
+}

monitor/src/main/java/netwatch/monitor/entities/Observation.java

@@ -0,0 +1,25 @@
+package netwatch.monitor.entities;
+
+import java.io.Serializable;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+// This class represents the "observes" entity in the database.
+// The Primary Key is the composite field "observationId" defined by the Embedded class {@link ObservationId}.
+// It represents the Many-To-Many association table between "utilities" and "contacts" tables.
+// @author Antonio Scardace
+// @version 1.0
+
+@NoArgsConstructor
+@AllArgsConstructor
+@Data
+public class Observation implements Serializable {
+
+    private ObservationId observationId;
+
+    private Utility utility;
+    private Contact contact;
+    private String environment;
+}

monitor/src/main/java/netwatch/monitor/entities/ObservationId.java

@@ -0,0 +1,22 @@
+package netwatch.monitor.entities;
+
+import java.io.Serializable;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+// It represents a composite Primary Key for the entity {@link Observation} of the table "observes".
+// It is composed by "address" and "contact" fields. They are both Foreign Keys.
+// Respectively, they are the utility address and its referent contact.
+// @author Antonio Scardace
+// @version 1.0
+
+@NoArgsConstructor
+@AllArgsConstructor
+@Data
+public class ObservationId implements Serializable {
+
+    private String address;
+    private String contact;
+}

monitor/src/main/java/netwatch/monitor/entities/Utility.java

@@ -0,0 +1,22 @@
+package netwatch.monitor.entities;
+
+import java.io.Serializable;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+// This class represents the "utilities" entity in the database.
+// The Primary Key is the field "address".
+// @author Antonio Scardace
+// @version 1.0
+
+@NoArgsConstructor
+@AllArgsConstructor
+@Data
+public class Utility implements Serializable {
+
+    private String address;
+    private String name;
+    private String type;
+}

monitor/src/main/java/netwatch/monitor/requests/IRequest.java

@@ -0,0 +1,9 @@
+package netwatch.monitor.requests;
+
+// Interface defining methods to handle address-related operations.
+// @author Antonio Scardace
+// @version 1.0
+
+public interface IRequest {
+    public Boolean request(String address);
+}

monitor/src/main/java/netwatch/monitor/requests/PingRequest.java

@@ -0,0 +1,34 @@
+package netwatch.monitor.requests;
+
+import java.io.IOException;
+import java.net.InetAddress;
+
+import lombok.extern.java.Log;
+
+// Implementation of {@link IRequest} for handling ping-related operations.
+// It supports IPv4 and IPv6 addresses. The use of their machine name is discouraged.
+// The timeout (the time before the call aborts) is set to 4000ms (4 seconds).
+// @author Antonio Scardace
+// @version 1.0
+
+@Log
+public class PingRequest implements IRequest {
+
+    private final Integer timeoutMs;
+
+    public PingRequest() {
+        this.timeoutMs = 4000;
+    }
+
+    @Override
+    public Boolean request(String ip) {
+        try {
+            InetAddress address = InetAddress.getByName(ip);
+            return address.isReachable(this.timeoutMs);
+        }
+        catch(IOException e) {
+            log.warning(e.getMessage());
+            return false;
+        }
+    }
+}

monitor/src/main/java/netwatch/monitor/requests/RequestCreator.java

@@ -0,0 +1,18 @@
+package netwatch.monitor.requests;
+
+// Factory class to create {@link IRequest} instances based on the type.
+// Factory-Method Design Pattern used to make the Request component modular.
+// @author Antonio Scardace
+// @version 1.0
+
+public class RequestCreator {
+
+    private RequestCreator() {
+
+    }
+
+    public static IRequest getRequest(String type) {
+        if (type.equals("ip")) return new PingRequest();
+        throw new IllegalArgumentException("Unknown Request type " + type);
+    }
+}