From 1e023b432920692f99a4e5b9d50369b8651956c5 Mon Sep 17 00:00:00 2001
From: Kai Moritz <kai@juplo.de>
Date: Tue, 6 May 2025 20:40:27 +0200
Subject: [PATCH] Separater ConsumerRunner

---
 pom.xml                                       | 36 ++++---------
 src/main/java/de/juplo/kafka/Application.java | 14 +++++
 .../juplo/kafka/ApplicationConfiguration.java | 21 ++++++++
 .../de/juplo/kafka/ApplicationProperties.java | 17 ++++++
 .../java/de/juplo/kafka/ConsumerRunner.java   | 40 ++++++++++++++
 .../java/de/juplo/kafka/ExampleConsumer.java  | 53 ++-----------------
 src/main/resources/application.yml            |  7 +++
 7 files changed, 115 insertions(+), 73 deletions(-)
 create mode 100644 src/main/java/de/juplo/kafka/Application.java
 create mode 100644 src/main/java/de/juplo/kafka/ApplicationConfiguration.java
 create mode 100644 src/main/java/de/juplo/kafka/ApplicationProperties.java
 create mode 100644 src/main/java/de/juplo/kafka/ConsumerRunner.java
 create mode 100644 src/main/resources/application.yml

diff --git a/pom.xml b/pom.xml
index a100717..9c40eb5 100644
--- a/pom.xml
+++ b/pom.xml
@@ -22,6 +22,14 @@
   </properties>
 
   <dependencies>
+    <dependency>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-web</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-actuator</artifactId>
+    </dependency>
     <dependency>
       <groupId>org.apache.kafka</groupId>
       <artifactId>kafka-clients</artifactId>
@@ -31,43 +39,21 @@
       <artifactId>lombok</artifactId>
       <scope>compile</scope>
     </dependency>
-    <dependency>
-      <groupId>ch.qos.logback</groupId>
-      <artifactId>logback-classic</artifactId>
-    </dependency>
   </dependencies>
 
   <build>
     <plugins>
       <plugin>
-        <groupId>org.apache.maven.plugins</groupId>
-        <artifactId>maven-dependency-plugin</artifactId>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-maven-plugin</artifactId>
         <executions>
           <execution>
-            <id>copy-dependencies</id>
-            <phase>package</phase>
             <goals>
-              <goal>copy-dependencies</goal>
+              <goal>build-info</goal>
             </goals>
-            <configuration>
-              <outputDirectory>${project.build.directory}/libs</outputDirectory>
-            </configuration>
           </execution>
         </executions>
       </plugin>
-      <plugin>
-        <groupId>org.apache.maven.plugins</groupId>
-        <artifactId>maven-jar-plugin</artifactId>
-        <configuration>
-          <archive>
-            <manifest>
-              <addClasspath>true</addClasspath>
-              <classpathPrefix>libs/</classpathPrefix>
-              <mainClass>de.juplo.kafka.ExampleConsumer</mainClass>
-            </manifest>
-          </archive>
-        </configuration>
-      </plugin>
       <plugin>
         <groupId>pl.project13.maven</groupId>
         <artifactId>git-commit-id-plugin</artifactId>
diff --git a/src/main/java/de/juplo/kafka/Application.java b/src/main/java/de/juplo/kafka/Application.java
new file mode 100644
index 0000000..cc1d580
--- /dev/null
+++ b/src/main/java/de/juplo/kafka/Application.java
@@ -0,0 +1,14 @@
+package de.juplo.kafka;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+
+@SpringBootApplication
+public class Application
+{
+  public static void main(String args[])
+  {
+    SpringApplication.run(Application.class, args);
+  }
+}
diff --git a/src/main/java/de/juplo/kafka/ApplicationConfiguration.java b/src/main/java/de/juplo/kafka/ApplicationConfiguration.java
new file mode 100644
index 0000000..76659d4
--- /dev/null
+++ b/src/main/java/de/juplo/kafka/ApplicationConfiguration.java
@@ -0,0 +1,21 @@
+package de.juplo.kafka;
+
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+
+@Configuration
+@EnableConfigurationProperties(ApplicationProperties.class)
+public class ApplicationConfiguration
+{
+  @Bean
+  public ExampleConsumer exampleConsumer(ApplicationProperties properties)
+  {
+    return new ExampleConsumer(
+      properties.getBroker(),
+      properties.getTopic(),
+      properties.getGroupId(),
+      properties.getClientId());
+  }
+}
diff --git a/src/main/java/de/juplo/kafka/ApplicationProperties.java b/src/main/java/de/juplo/kafka/ApplicationProperties.java
new file mode 100644
index 0000000..5743b77
--- /dev/null
+++ b/src/main/java/de/juplo/kafka/ApplicationProperties.java
@@ -0,0 +1,17 @@
+package de.juplo.kafka;
+
+import lombok.Getter;
+import lombok.Setter;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
+
+@ConfigurationProperties(prefix = "juplo.consumer")
+@Getter
+@Setter
+public class ApplicationProperties
+{
+  private String broker;
+  private String topic;
+  private String groupId;
+  private String clientId;
+}
diff --git a/src/main/java/de/juplo/kafka/ConsumerRunner.java b/src/main/java/de/juplo/kafka/ConsumerRunner.java
new file mode 100644
index 0000000..b9a077a
--- /dev/null
+++ b/src/main/java/de/juplo/kafka/ConsumerRunner.java
@@ -0,0 +1,40 @@
+package de.juplo.kafka;
+
+import jakarta.annotation.PreDestroy;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Component;
+
+import java.time.Duration;
+
+
+@Component
+@Slf4j
+public class ConsumerRunner
+{
+  private final ExampleConsumer exampleConsumer;
+  private final Thread worker;
+
+  public ConsumerRunner(ExampleConsumer exampleConsumer)
+  {
+    this.exampleConsumer = exampleConsumer;
+    this.worker = new Thread(exampleConsumer, "ConsumerRunner-" + exampleConsumer);
+    log.info("Starting consumer: {}", exampleConsumer);
+    this.worker.start();
+  }
+
+  @PreDestroy
+  public void close()
+  {
+    log.info("Stopping: {}", exampleConsumer);
+    exampleConsumer.consumer.wakeup();
+    try
+    {
+      worker.join(Duration.ofSeconds(30));
+    }
+    catch (InterruptedException e)
+    {
+      log.error("Fehler: {} - {}", exampleConsumer, e.toString());
+    }
+    log.info("Done! {}", exampleConsumer);
+  }
+}
diff --git a/src/main/java/de/juplo/kafka/ExampleConsumer.java b/src/main/java/de/juplo/kafka/ExampleConsumer.java
index 7be827e..beaec07 100644
--- a/src/main/java/de/juplo/kafka/ExampleConsumer.java
+++ b/src/main/java/de/juplo/kafka/ExampleConsumer.java
@@ -1,5 +1,6 @@
 package de.juplo.kafka;
 
+import lombok.ToString;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.kafka.clients.consumer.ConsumerRecord;
 import org.apache.kafka.clients.consumer.ConsumerRecords;
@@ -14,13 +15,13 @@ import java.util.Properties;
 
 
 @Slf4j
-public class ExampleConsumer
+@ToString(of = "id")
+public class ExampleConsumer implements Runnable
 {
   private final String id;
   private final String topic;
-  private final Consumer<String, String> consumer;
+  final Consumer<String, String> consumer;
 
-  private volatile boolean running = false;
   private long consumed = 0;
 
   public ExampleConsumer(
@@ -42,13 +43,13 @@ public class ExampleConsumer
   }
 
 
+  @Override
   public void run()
   {
     try
     {
       log.info("{} - Subscribing to topic {}", id, topic);
       consumer.subscribe(Arrays.asList(topic));
-      running = true;
 
       while (true)
       {
@@ -80,7 +81,6 @@ public class ExampleConsumer
       log.info("{} - Closing the KafkaConsumer", id);
       consumer.close();
       log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
-      running = false;
     }
   }
 
@@ -94,48 +94,5 @@ public class ExampleConsumer
     consumed++;
     log.info("{} - partition={}-{}, offset={}: {}={}", id, topic, partition, offset, key, value);
   }
-
-
-  public static void main(String[] args) throws Exception
-  {
-    if (args.length != 4)
-    {
-      log.error("Four arguments required!");
-      log.error("args[0]: Broker-Address");
-      log.error("args[1]: Topic");
-      log.error("args[2]: Group-ID");
-      log.error("args[3]: Unique Client-ID");
-      System.exit(1);
-      return;
-    }
-
-
-    log.info(
-      "Running ExampleConsumer: broker={}, topic={}, group-id={}, client-id={}",
-      args[0],
-      args[1],
-      args[2],
-      args[3]);
-
-    ExampleConsumer instance = new ExampleConsumer(args[0], args[1], args[2], args[3]);
-
-    Runtime.getRuntime().addShutdownHook(new Thread(() ->
-    {
-      instance.consumer.wakeup();
-
-      while (instance.running)
-      {
-        log.info("Waiting for main-thread...");
-        try
-        {
-          Thread.sleep(1000);
-        }
-        catch (InterruptedException e) {}
-      }
-      log.info("Shutdown completed.");
-    }));
-
-    instance.run();
-  }
 }
 
diff --git a/src/main/resources/application.yml b/src/main/resources/application.yml
new file mode 100644
index 0000000..3ce636e
--- /dev/null
+++ b/src/main/resources/application.yml
@@ -0,0 +1,7 @@
+juplo:
+  consumer:
+    broker: localhost:9092
+    topic: test
+    group-id: my-group
+    client-id: IntelliJ
+
-- 
2.20.1