tencent cloud

Overview

This document describes how to access CKafka to receive/send messages with the SDK for Java through SASL_PLAINTEXT on the public network.

Prerequisites

• You have installed JDK 1.8 or later
• You have installed Maven 2.5 or later
• You have configured an ACL policy
• You have downloaded the demo

Directions

Step 1. Create resources in the console

1. Create an access point.
   1. On the Instance List page in the CKafka console, click the target instance ID to enter the instance details page.
   2. In Basic Info > Access Mode, click Add a routing policy. In the pop-up window, select Route Type: Public domain name access, Access Mode: SASL_PLAINTEXT.
      
2. Create a role.
   On the User Management tab page, create a role and set the password.
   
3. Create a topic.
   Create a topic on the Topic Management tab page as instructed in Topic Management.

Step 2. Add the configuration file

1. Add the following dependencies to the pom.xml file:
   <dependencies>
      <dependency>
         <groupid>org.apache.kafka</groupid>
         <artifactid>kafka-clients</artifactid>
         <version>2.1.0</version>
      </dependency>
      <dependency>
         <groupid>org.slf4j</groupid>
         <artifactid>slf4j-api</artifactid>
         <version>1.7.5</version>
      </dependency>
      <dependency>
         <groupid>org.slf4j</groupid>
         <artifactid>slf4j-simple</artifactid>
         <version>1.6.4</version>
      </dependency>
   </dependencies>

2. Create a JAAS configuration file named ckafka_client_jaas.conf and modify it with the user created on the User Management tab page.
   KafkaClient {
   org.apache.kafka.common.security.plain.PlainLoginModule required
   username="yourinstance#yourusername"
   password="yourpassword";
   };

   Note

   Set username to a value in the format of instance ID + # + configured username, and password to a configured password.

3. Create a Kafka configuration file named kafka.properties.
   ## Configure the accessed network by copying the information in the **Network** column in the **Access Mode** section on the instance details** page in the console
   bootstrap.servers=ckafka-xxxxxxx
   ## Configure the topic by copying the information on the **Topic Management** page in the console
   topic=XXX
   ## Configure the consumer group as needed
   group.id=XXX
   ## SASL configuration
   java.security.auth.login.config.plain=/xxxx/ckafka_client_jaas.conf

   Parameter	Description
   bootstrap.servers	Accessed network, which can be copied in the **Network** column in the Access Mode section on the instance details page in the console.
   topic	Topic name, which can be copied in Topic Management on the instance details page in the console.
   group.id	You can customize it. After the demo runs successfully, you can see the consumer on the Consumer Group page.
   java.security.auth.login.config.plain	Enter the path of the JAAS configuration file ckafka_client_jaas.conf.

4. Create a configuration file loading program named CKafkaConfigurer.java.
   public class CKafkaConfigurer {
   
       private static Properties properties;
   
       public static void configureSaslPlain() {
           //If you have used the `-D` parameter or another method to set the path, do not set it again here
           if (null == System.getProperty("java.security.auth.login.config")) {
               // Replace `XXX` with your own path
               System.setProperty("java.security.auth.login.config",
                       getCKafkaProperties().getProperty("java.security.auth.login.config.plain"));
           }
       }
   
       public synchronized static Properties getCKafkaProperties() {
           if (null != properties) {
               return properties;
           }
           //Obtain the content of the configuration file `kafka.properties`
           Properties kafkaProperties = new Properties();
           try {
               kafkaProperties.load(CKafkaProducerDemo.class.getClassLoader().getResourceAsStream("kafka.properties"));
           } catch (Exception e){
               System.out.println("getCKafkaProperties error");
           }
           properties = kafkaProperties;
           return kafkaProperties;
       }
   }

Step 3. Send messages

1. Create a message sending program named KafkaSaslProducerDemo.java.
   public class KafkaSaslProducerDemo {
    public static void main(String[] args) {
      //Set the path to the JAAS configuration file
      CKafkaConfigurer.configureSaslPlain();
       //Load `kafka.properties`
      Properties kafkaProperties = CKafkaConfigurer.getCKafkaProperties();
       Properties props = new Properties();
      //Set the access point. Obtain the access point of the topic via the console
      props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG,
              kafkaProperties.getProperty("bootstrap.servers"));
       //
      //  Public network access through SASL_PLAINTEXT
      //
      props.put(CommonClientConfigs.SECURITY_PROTOCOL_CONFIG, "SASL_PLAINTEXT");
      //  Select `PLAIN` for the SASL mechanism.
      props.put(SaslConfigs.SASL_MECHANISM, "PLAIN");
       //Set the method for serializing Kafka messages
      props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG,
              "org.apache.kafka.common.serialization.StringSerializer");
      props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG,
              "org.apache.kafka.common.serialization.StringSerializer");
      //Set the maximum request wait time
      props.put(ProducerConfig.MAX_BLOCK_MS_CONFIG, 30 * 1000);
      //Set the number of retries for the client
      props.put(ProducerConfig.RETRIES_CONFIG, 5);
      //Set the retry interval for the client
      props.put(ProducerConfig.RECONNECT_BACKOFF_MS_CONFIG, 3000);
      // If `ack` is 0, the producer will not wait for acknowledgment from the broker, and the retry configuration will not take effect. If traffic throttling is triggered, the connection will be closed.
      // If `ack` is 1, the broker leader will directly return `ack` without waiting for acknowledgment from all broker followers
      // If `ack` is `all`, the broker leader will return `ack` only after receiving acknowledgment from all broker followers
      props.put(ProducerConfig.ACKS_CONFIG, "all");
      //Create a producer object. Note: a producer object is thread-safe, and generally one producer object is sufficient for a process.
      KafkaProducer<string, string=""> producer = new KafkaProducer<>(props);
       //Create a Kafka message
      String topic = kafkaProperties.getProperty("topic"); //Topic of the message. Enter the topic you created in the console.
      String value = "this is ckafka msg value"; //Content of the message.
       try {
         //Batch obtaining future objects can speed up the process, but the batch size should not be too large
         List<future<recordmetadata>> futures = new ArrayList<>(128);
         for (int i = 0; i < 100; i++) {
            //Send the message and obtain a future object
            ProducerRecord<string, string=""> kafkaMessage = new ProducerRecord<>(topic,
                    value + ": " + i);
            Future<recordmetadata> metadataFuture = producer.send(kafkaMessage);
            futures.add(metadataFuture);
          }
         producer.flush();
         for (Future<recordmetadata> future : futures) {
            //Sync the result that the future object is obtained
            RecordMetadata recordMetadata = future.get();
            System.out.println("Produce ok:" + recordMetadata.toString());
         }
      } catch (Exception e){
         //If the sending still fails after client internal retries, the system needs to report and handle the error
         System.out.println("error occurred");
      }
   }
   }

2. Compile and run KafkaSaslProducerDemo.java to send messages.
3. View the execution result (output).
   Produce ok:ckafka-topic-demo-0@198
   Produce ok:ckafka-topic-demo-0@199

4. On the Topic Management tab page on the instance details page in the CKafka console, select the target topic, and click More > Message Query to view the message just sent.
   

Step 4. Consume messages

1. Create a program named KafkaSaslConsumerDemo.java for a single consumer to subscribe to messages.
   public class KafkaSaslConsumerDemo {
   
      public static void main(String[] args) {
         //Set the path to the JAAS configuration file
         CKafkaConfigurer.configureSaslPlain();
   
         //Load `kafka.properties`
         Properties kafkaProperties = CKafkaConfigurer.getCKafkaProperties();
   
         Properties props = new Properties();
         //Set the access point. Obtain the access point of the topic via the console.
         props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG,
                 kafkaProperties.getProperty("bootstrap.servers"));
   
         //
         //  Public network access through SASL_PLAINTEXT
         //
         props.put(CommonClientConfigs.SECURITY_PROTOCOL_CONFIG, "SASL_PLAINTEXT");
         //  Select `PLAIN` for the SASL mechanism
         props.put(SaslConfigs.SASL_MECHANISM, "PLAIN");
   
         // Set the consumer timeout period
         //If the consumer does not return a heartbeat message within the interval, the broker will determine that the consumer is not alive, and then remove the consumer from the consumer group and trigger rebalancing. The default value is 30s.
         props.put(ConsumerConfig.SESSION_TIMEOUT_MS_CONFIG, 30000);
         // Set the maximum time interval between two polls
         // Before v0.10.1.0, these two concepts were mixed and both represented by `session.timeout.ms`
         props.put(ConsumerConfig.MAX_POLL_INTERVAL_MS_CONFIG, 30000);
         //Set the maximum number of messages that can be polled at a time
         //Do not set this parameter to an excessively large value. If polled messages are not all consumed before the next poll starts, load balancing is triggered and lagging occurs.
         props.put(ConsumerConfig.MAX_POLL_RECORDS_CONFIG, 30);
         //Set the method for deserializing messages
         props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG,
                 "org.apache.kafka.common.serialization.StringDeserializer");
         props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG,
                 "org.apache.kafka.common.serialization.StringDeserializer");
         //Set the consumer group of the current consumer instance after you apply for one in the console
         //The instances in the same consumer group consume messages in load balancing mode
         props.put(ConsumerConfig.GROUP_ID_CONFIG, kafkaProperties.getProperty("group.id"));
         //Create a consumer object, which means generating a consumer instance
         KafkaConsumer<string, string=""> consumer = new KafkaConsumer<string, string="">(props);
         //Set one or more topics to which the consumer group subscribes
         //You are advised to subscribe to the same topics if the values of GROUP_ID_CONFIG are the same
         List<string> subscribedTopics = new ArrayList<string>();
         //If you want to subscribe to multiple topics, add the topics here
         //You must create the topics in the console in advance
         String topicStr = kafkaProperties.getProperty("topic");
         String[] topics = topicStr.split(",");
         for (String topic : topics) {
            subscribedTopics.add(topic.trim());
         }
         consumer.subscribe(subscribedTopics);
   
         //Consume messages in loop
         while (true) {
            try {
               ConsumerRecords<string, string=""> records = consumer.poll(1000);
               //All messages must be consumed before the next poll, and the total duration cannot exceed the timeout interval specified by `SESSION_TIMEOUT_MS_CONFIG`
               for (ConsumerRecord<string, string=""> record : records) {
                  System.out.println(
                          String.format("Consume partition:%d offset:%d", record.partition(),
                                  record.offset()));
               }
            } catch (Exception e){
               System.out.println("consumer error!");
            }
         }
      }
   }

2. Compile and run KafkaSaslConsumerDemo.java to consume messages.
3. View the execution result (output).
   Consume partition:0 offset:298
   Consume partition:0 offset:299

4. On the Consumer Group page in the Ckafka console, select the consumer group name, enter the topic name, and click Query Details to view the consumption details.