Kafka学习(一)--- Quickstart

分类 : 数据库

参考官网:http://kafka.apache.org/quickstart

一、下载Kafka

官网下载地址 http://kafka.apache.org/downloads

截至2019年7月8日 最新版本为 2.3.0 2.12为编译的scala版本 2.3.0为kafka版本

  • Scala 2.12  - kafka_2.12-2.3.0.tgz (asc, sha512)
    解压
    > tar -xzf kafka_2.12-2.3.0.tgz
    > cd kafka_2.12-2.3.0

二、启动服务

要先启动zookeeper kafka内置了一个 也可以不用

> bin/zookeeper-server-start.sh config/zookeeper.properties[2013-04-2215:01:37,495] INFO Reading configuration from: config/zookeeper.properties (org.apache.zookeeper.server.quorum.QuorumPeerConfig)...> bin/kafka-server-start.sh config/server.properties[2013-04-2215:01:47,028] INFO Verifying properties (kafka.utils.VerifiableProperties)[2013-04-2215:01:47,051] INFO Property socket.send.buffer.bytes is overridden to1048576 (kafka.utils.VerifiableProperties)...

三、创建topic

replication-factor为1   partitions为1> bin/kafka-topics.sh --create --bootstrap-server localhost:9092 --replication-factor 1 --partitions 1 --topic test查看topic> bin/kafka-topics.sh --list --bootstrap-server localhost:9092test

也可以不创建topic 设置自动创建 当publish的时候

四、发送消息

用command line client 进行测试 一行就是一条消息

> bin/kafka-console-producer.sh --broker-list localhost:9092 --topic testThis is a messageThis is another message

五、消费者

command line consumer 可以接收消息

> bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic test --from-beginningThis is a messageThis is another message

六、设置多broker集群

单broker没有意思 我们可以设置三个broker

首先为每个broker 复制配置文件

> cp config/server.properties config/server-1.properties> cp config/server.properties config/server-2.properties

然后编辑

config/server-1.properties:    broker.id=1    listeners=PLAINTEXT://:9093    log.dirs=/tmp/kafka-logs-1 config/server-2.properties:    broker.id=2    listeners=PLAINTEXT://:9094    log.dirs=/tmp/kafka-logs-2

broker.id是唯一的 cluster中每一个node的名字 我们在same machine上 所有要设置listeners和log.dirs 以防冲突

建一个topic 一个partitions 三个replication-factor

> bin/kafka-topics.sh --create --bootstrap-server localhost:9092 --replication-factor 3 --partitions 1 --topic my-replicated-topic用describe看看都是什么情况> bin/kafka-topics.sh --describe --bootstrap-server localhost:9092 --topic my-replicated-topicTopic:my-replicated-topic   PartitionCount:1ReplicationFactor:3Configs:    Topic: my-replicated-topic  Partition:0Leader:1Replicas:1,2,0Isr:1,2,0
  • 有几个概念 :

  • "leader" is the node responsible for all reads and writes for the given partition. Each node will be the leader for a randomly selected portion of the partitions.

  • "replicas" is the list of nodes that replicate the log for this partition regardless of whether they are the leader or even if they are currently alive.

  • "isr" is the set of "in-sync" replicas. This is the subset of the replicas list that is currently alive and caught-up to the leader.

    刚才那个topic

    bin/kafka-topics.sh --describe --bootstrap-server localhost:9092 --topic test
    Topic:test PartitionCount:1 ReplicationFactor:1 Configs:
    Topic: test Partition: 0 Leader: 0 Replicas: 0 Isr: 0

发送 接收

> bin/kafka-console-producer.sh --broker-list localhost:9092 --topic my-replicated-topic...my test message 1my test message 2^C> bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --from-beginning --topic my-replicated-topic...my test message 1my test message 2^C

试一下容错 fault-tolerance

> ps aux | grep server-1.properties7564 ttys002    0:15.91/System/Library/Frameworks/JavaVM.framework/Versions/1.8/Home/bin/java...> kill -97564看一下变化:Leader换了一个  因为1被干掉了> bin/kafka-topics.sh --describe --bootstrap-server localhost:9092 --topic my-replicated-topicTopic:my-replicated-topic   PartitionCount:1ReplicationFactor:3Configs:    Topic: my-replicated-topic  Partition:0Leader:2Replicas:1,2,0Isr:2,0还是收到了消息> bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --from-beginning --topic my-replicated-topic...my test message 1my test message 2^C

七、使用kafka import/export data

刚才都是console 的数据,其他的sources other systems呢 用Kafka Connect

弄一个数据> echo -e "foo\nbar" > test.txt启动  指定配置文件> bin/connect-standalone.sh config/connect-standalone.properties config/connect-file-source.properties config/connect-file-sink.properties验证一下> more test.sink.txtfoobar消费者端> bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic connect-test --from-beginning{"schema":{"type":"string","optional":false},"payload":"foo"}{"schema":{"type":"string","optional":false},"payload":"bar"}...可以继续写入> echo Another line>> test.txt

八、使用Kafka Streams

http://kafka.apache.org/22/documentation/streams/quickstart

WordCountDemo

https://github.com/apache/kafka/blob/2.2/streams/examples/src/main/java/org/apache/kafka/streams/examples/wordcount/WordCountDemo.java

代码片段

// Serializers/deserializers (serde) for String and Long typesfinal Serde<String> stringSerde = Serdes.String();final Serde<Long> longSerde = Serdes.Long(); // Construct a `KStream` from the input topic "streams-plaintext-input", where message values// represent lines of text (for the sake of this example, we ignore whatever may be stored// in the message keys).KStream<String, String> textLines = builder.stream("streams-plaintext-input",    Consumed.with(stringSerde, stringSerde); KTable<String, Long> wordCounts = textLines    // Split each text line, by whitespace, into words.    .flatMapValues(value -> Arrays.asList(value.toLowerCase().split("\\W+")))     // Group the text words as message keys    .groupBy((key, value) -> value)     // Count the occurrences of each word (message key).    .count() // Store the running counts as a changelog stream to the output topic.wordCounts.toStream().to("streams-wordcount-output", Produced.with(Serdes.String(), Serdes.Long()));

建一个 Kafka producer 指定input topic output topic

> bin/kafka-topics.sh --create \--bootstrap-server localhost:9092 \--replication-factor 1 \--partitions 1 \--topic streams-wordcount-output \--config cleanup.policy=compactCreated topic "streams-wordcount-output".

启动WordCount demo application

bin/kafka-run-class.shorg.apache.kafka.streams.examples.wordcount.WordCountDemo

启动一个生产者写数据

> bin/kafka-console-producer.sh --broker-list localhost:9092 --topic streams-plaintext-inputall streams lead to kafkahello kafka streams

启动一个消费者接数据

> bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 \    --topic streams-wordcount-output \    --from-beginning \    --formatter kafka.tools.DefaultMessageFormatter \    --property print.key=true \    --property print.value=true \    --propertykey.deserializer=org.apache.kafka.common.serialization.StringDeserializer \    --property value.deserializer=org.apache.kafka.common.serialization.LongDeserializer    all     1streams 1lead    1to1kafka   1hello   1kafka   2streams 2kafka   1
在这个世界上,最重要的不是你所处的位置,而是你前进的方向!


分类: 数据库  发布: 2019-07-09-星期二   访问() .NET技术    Web前端    JAVA开发    语言编程    数据库    电脑知识    代码案例

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