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Flink 快速入门(随意翻译---不一定准确)

Flink 快速入门(随意翻译---不一定准确)

作者: 写Bug的张小天 | 来源:发表于2017-05-23 17:28 被阅读415次

    原文链接:https://ci.apache.org/projects/flink/flink-docs-release-1.3/quickstart/setup_quickstart.html

    Setup: Download and Start Flink

    Flink可以运行在Linux、Mac OS X以及Windows中,Flink运行的唯一条件就是安装Java

    7.X以上的版本的jdk。Windows用户请查看一下Flink on Windows文档,这个文档描述了如何在window运行单机的Flink。Flink on Windows:https://ci.apache.org/projects/flink/flink-docs-release-1.3/setup/flink_on_windows.html

    你可以通过下面的命令行来查看安装的Java版本是否正确:

    java -version

    如果你安装的是Java 8的话,会返回下面的信息:

    java version"1.8.0_111"

    Java(TM)SE Runtime Environment(build 1.8.0_111-b14)

    Java HotSpot(TM)64-Bit Server VM(build 25.111-b14, mixed mode)

    Downloadand Compile

    从Flink的代码库中clone代码,如下:

    $git clone https://github.com/apache/flink.git

    $cdflink

    $mvn clean package -DskipTests# this will take up to 10 minutes

    $cdbuild-target# this is where Flink is installed to

    Starta Local Flink Cluster

    $./bin/start-local.sh# Start Flink

    通过http://localhost:8081来检查JobManager的Web前台,确保每一个进程都起来了。在这个Web前台中应该只有一个TaskManager实例。

    还可以通过检查日志目录中的日志文件来判断系统是否正常运行

    $tail log/flink-*-jobmanager-*.log

    INFO ... - Starting JobManager

    INFO ... - Starting JobManager web frontend

    INFO ... - Web frontend listening at 127.0.0.1:8081

    INFO ... - Registered TaskManager at 127.0.0.1(akka://flink/user/taskmanager)

    Readthe Code

    你可以在GitHub中查看到这个SocketWindowWordCount实例完整的Java代码和Scala代码。

    Scala:

    object SocketWindowWordCount {  

      def main(args: Array[String]) : Unit = {        // the port to connect to 

           val port: Int = try {            

                ParameterTool.fromArgs(args).getInt("port")        

           } catch {           

                 case e: Exception => { 

                   System.err.println("No port specified. Please run 'SocketWindowWordCount --port'")

                   return

            }

    }

    // get the execution environment

    val env: StreamExecutionEnvironment = StreamExecutionEnvironment.getExecutionEnvironment

    // get input data by connecting to the socket

    val text = env.socketTextStream("localhost", port, '\n')

    // parse the data, group it, window it, and aggregate the counts

    val windowCounts = text.flatMap { w => w.split("\\s") }

                                    .map { w => WordWithCount(w, 1) }

                                   .keyBy("word")

                                   .timeWindow(Time.seconds(5), Time.seconds(1))

                                  .sum("count")

    // print the results with a single thread, rather than in parallel

    windowCounts.print().setParallelism(1)

    env.execute("Socket Window WordCount")

    }

    // Data type for words with count

    case class WordWithCount(word: String, count: Long)

    }

    Runthe Example

    现在我们将去执行这个Flink程序,这个程序将去读取socket中产生的文本,并且每隔5秒打印一下前5秒内产生的不同的单次产生的次数。

    首先,我们通过netcat来打开一个本地的服务:

    $nc -l 9000

    提交Flink程序

    $./bin/flink run examples/streaming/SocketWindowWordCount.jar --port 9000

    Cluster configuration: Standalone cluster with JobManager at /127.0.0.1:6123

    Using address 127.0.0.1:6123 to connect to JobManager.

    JobManager web interface address http://127.0.0.1:8081

    Starting execution of program

    Submitting job with JobID: 574a10c8debda3dccd0c78a3bde55e1b. Waitingforjob completion.

    Connected to JobManager at Actor[akka.tcp://flink@127.0.0.1:6123/user/jobmanager#297388688]

    11/04/2016 14:04:50Job execution switched to status RUNNING.

    11/04/2016 14:04:50Source: Socket Stream -> Flat Map(1/1)switched to SCHEDULED

    11/04/2016 14:04:50Source: Socket Stream -> Flat Map(1/1)switched to DEPLOYING

    11/04/2016 14:04:50Fast TumblingProcessingTimeWindows(5000)of WindowedStream.main(SocketWindowWordCount.java:79)-> Sink: Unnamed(1/1)switched to SCHEDULED

    11/04/2016 14:04:51Fast TumblingProcessingTimeWindows(5000)of WindowedStream.main(SocketWindowWordCount.java:79)-> Sink: Unnamed(1/1)switched to DEPLOYING

    11/04/2016 14:04:51Fast TumblingProcessingTimeWindows(5000)of WindowedStream.main(SocketWindowWordCount.java:79)-> Sink: Unnamed(1/1)switched to RUNNING

    11/04/2016 14:04:51Source: Socket Stream -> Flat Map(1/1)switched to RUNNING

    程序将与socket连接并等待输入,你可以通过web前台来查看作业是否如预期执行。

    单词在一个间隔5秒的window(窗口)中执行并且打印到stdout中。监控JobManager的输出文件并写些文档到nc中。

    $nc -l 9000

    lorem ipsum

    ipsum ipsum ipsum

    bye

    只要单词源源不断的流入的话,.out文件将在时间窗口的最后截止时间打印出单词的计数:例如:

    $tail -f log/flink-*-jobmanager-*.out

    lorem : 1

    bye : 1

    ipsum : 4

    运行结束后可以停掉Flink:

    $./bin/stop-local.sh

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