使用Maven打包和运行Scala Spark项目

Question

我在Scala中编写了一个使用Spark的应用程序.我正在使用Maven打包应用程序,并在构建"超级"或"胖"jar时遇到问题.

我面临的问题是运行应用程序在IDE内运行正常,或者如果我提供非超级jar版本的依赖项作为java类路径,但如果我将uber jar作为uber jar,它就不起作用类路径,即

java -Xmx2G -cp target/spark-example-0.1-SNAPSHOT-jar-with-dependencies.jar debug.spark_example.Example data.txt 

不起作用.我收到以下错误消息:

ERROR SparkContext: Error initializing SparkContext.
com.typesafe.config.ConfigException$Missing: No configuration setting found for key 'akka.version'
    at com.typesafe.config.impl.SimpleConfig.findKey(SimpleConfig.java:124)
    at com.typesafe.config.impl.SimpleConfig.find(SimpleConfig.java:145)
    at com.typesafe.config.impl.SimpleConfig.find(SimpleConfig.java:151)
    at com.typesafe.config.impl.SimpleConfig.find(SimpleConfig.java:159)
    at com.typesafe.config.impl.SimpleConfig.find(SimpleConfig.java:164)
    at com.typesafe.config.impl.SimpleConfig.getString(SimpleConfig.java:206)
    at akka.actor.ActorSystem$Settings.<init>(ActorSystem.scala:168)
    at akka.actor.ActorSystemImpl.<init>(ActorSystem.scala:504)
    at akka.actor.ActorSystem$.apply(ActorSystem.scala:141)
    at akka.actor.ActorSystem$.apply(ActorSystem.scala:118)
    at org.apache.spark.util.AkkaUtils$.org$apache$spark$util$AkkaUtils$$doCreateActorSystem(AkkaUtils.scala:122)
    at org.apache.spark.util.AkkaUtils$$anonfun$1.apply(AkkaUtils.scala:54)
    at org.apache.spark.util.AkkaUtils$$anonfun$1.apply(AkkaUtils.scala:53)
    at org.apache.spark.util.Utils$$anonfun$startServiceOnPort$1.apply$mcVI$sp(Utils.scala:1991)
    at scala.collection.immutable.Range.foreach$mVc$sp(Range.scala:160)
    at org.apache.spark.util.Utils$.startServiceOnPort(Utils.scala:1982)
    at org.apache.spark.util.AkkaUtils$.createActorSystem(AkkaUtils.scala:56)
    at org.apache.spark.rpc.akka.AkkaRpcEnvFactory.create(AkkaRpcEnv.scala:245)
    at org.apache.spark.rpc.RpcEnv$.create(RpcEnv.scala:52)
    at org.apache.spark.SparkEnv$.create(SparkEnv.scala:247)
    at org.apache.spark.SparkEnv$.createDriverEnv(SparkEnv.scala:188)
    at org.apache.spark.SparkContext.createSparkEnv(SparkContext.scala:267)
    at org.apache.spark.SparkContext.<init>(SparkContext.scala:424)
    at debug.spark_example.Example$.main(Example.scala:9)
    at debug.spark_example.Example.main(Example.scala)

我非常感谢帮助理解我需要添加到pom.xml文件中的内容以及为什么我需要添加它以使其工作.

我在线搜索并找到了以下资源,我尝试过(参见pom),但无法开始工作:

1)Spark用户邮件列表:http://apache-spark-user-list.1001560.n3.nabble.com/Packaging-a-spark-job-using-maven-td5615.html

2)如何打包spark scala应用程序

我有一个简单的例子来演示这个问题,一个简单的1类项目(src/main/scala/debug/spark_example/Example.scala):

package debug.spark_example

import org.apache.spark.{SparkConf, SparkContext}

object Example {
  def main(args: Array[String]): Unit = {
    val sc = new SparkContext(new SparkConf().setAppName("Test").setMaster("local[2]"))
    val lines = sc.textFile(args(0))
    val lineLengths = lines.map(s => s.length)
    val totalLength = lineLengths.reduce((a, b) => a + b)
    lineLengths.foreach(println)
     println(totalLength)
   }
 }

这是pom.xml文件:

<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 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>debug.spark-example</groupId>
  <artifactId>spark-example</artifactId>
  <version>0.1-SNAPSHOT</version>
  <inceptionYear>2015</inceptionYear>
  <properties>
    <scala.majorVersion>2.11</scala.majorVersion>
    <scala.minorVersion>.2</scala.minorVersion>
    <spark.version>1.4.1</spark.version>
  </properties>


  <repositories>
    <repository>
      <id>scala-tools.org</id>
      <name>Scala-Tools Maven2 Repository</name>
      <url>http://scala-tools.org/repo-releases</url>
    </repository>
  </repositories>

  <pluginRepositories>
    <pluginRepository>
      <id>scala-tools.org</id>
      <name>Scala-Tools Maven2 Repository</name>
      <url>http://scala-tools.org/repo-releases</url>
    </pluginRepository>
  </pluginRepositories>

  <dependencies>
    <dependency>
      <groupId>org.scala-lang</groupId>
      <artifactId>scala-library</artifactId>
      <version>${scala.majorVersion}${scala.minorVersion}</version>
    </dependency>
    <dependency>
      <groupId>org.apache.spark</groupId>
      <artifactId>spark-core_${scala.majorVersion}</artifactId>
      <version>${spark.version}</version>
    </dependency>
  </dependencies>


  <build>
      <sourceDirectory>src/main/scala</sourceDirectory>
      <plugins>
        <plugin>
          <groupId>org.scala-tools</groupId>
          <artifactId>maven-scala-plugin</artifactId>
          <executions>
            <execution>
              <goals>
                <goal>compile</goal>
                <goal>testCompile</goal>
              </goals>
            </execution>
          </executions>
        </plugin>
        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-eclipse-plugin</artifactId>
      <configuration>
        <downloadSources>true</downloadSources>
        <buildcommands>
          <buildcommand>ch.epfl.lamp.sdt.core.scalabuilder</buildcommand>
        </buildcommands>
        <additionalProjectnatures>
          <projectnature>ch.epfl.lamp.sdt.core.scalanature</projectnature>
        </additionalProjectnatures>
        <classpathContainers>
          <classpathContainer>org.eclipse.jdt.launching.JRE_CONTAINER</classpathContainer>
          <classpathContainer>ch.epfl.lamp.sdt.launching.SCALA_CONTAINER</classpathContainer>
        </classpathContainers>
      </configuration>
    </plugin>
    <plugin>
      <artifactId>maven-assembly-plugin</artifactId>
      <version>2.4</version>
      <executions>
        <execution>
          <id>make-assembly</id>
          <phase>package</phase>
          <goals>
            <goal>attached</goal>
          </goals>
        </execution>
      </executions>
      <configuration>
        <tarLongFileMode>gnu</tarLongFileMode>
        <descriptorRefs>
          <descriptorRef>jar-with-dependencies</descriptorRef>
        </descriptorRefs>
      </configuration>
    </plugin>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-shade-plugin</artifactId>
      <version>2.2</version>
      <executions>
        <execution>
          <phase>package</phase>
          <goals>
            <goal>shade</goal>
          </goals>
          <configuration>
            <minimizeJar>false</minimizeJar>
            <createDependencyReducedPom>false</createDependencyReducedPom>
            <artifactSet>
              <includes>
                <!-- Include here the dependencies you want to be packed in your fat jar -->
                <include>*:*</include>
              </includes>
            </artifactSet>
            <filters>
              <filter>
                <artifact>*:*</artifact>
                <excludes>
                  <exclude>META-INF/*.SF</exclude>
                  <exclude>META-INF/*.DSA</exclude>
                  <exclude>META-INF/*.RSA</exclude>
                </excludes>
              </filter>
            </filters>
            <transformers>
              <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                <resource>reference.conf</resource>
              </transformer>
            </transformers>
          </configuration>
        </execution>
      </executions>
    </plugin>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-surefire-plugin</artifactId>
      <version>2.7</version>
      <configuration>
        <skipTests>true</skipTests>
      </configuration>
    </plugin>
  </plugins>
</build>
<reporting>
  <plugins>
    <plugin>
      <groupId>org.scala-tools</groupId>
      <artifactId>maven-scala-plugin</artifactId>
    </plugin>
  </plugins>
</reporting>
</project>

非常感谢您的帮助.

Answer 1

这可能和你的maven插件的顺序有关。您在项目中同时使用“maven-assemble-plugin”和“maven-shade-plugin”插件，它们都绑定到 maven 生命周期中的同一阶段。发生这种情况时，maven 按照插件在插件部分中出现的顺序执行插件，因此在您的情况下，它会执行程序集插件，然后是阴影插件。

根据您尝试运行的输出 jar 和您拥有的阴影转换，您可能需要相反的顺序。但是，您甚至可能不需要适合您的用例的程序集插件。您也许可以使用该target/spark-example-0.1-SNAPSHOT-shaded.jar文件。

<plugins>
  <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-shade-plugin</artifactId>
    <!-- SNIP -->
  </plugin>
  <plugin>
    <artifactId>maven-assembly-plugin</artifactId>
    <!-- SNIP -->
  </plugin>
</plugins>