Apache Spark Streaming的失敗集成測試

Question

我一直試圖通過一些我為Apache Spark項目編寫的單元/集成測試來追蹤問題。

使用Spark 1.1.1時，我的測試通過了。 當我嘗試升級到1.4.0（也嘗試過1.4.1）時，測試開始失敗。

我已經設法將重現問題所需的代碼減少到下面的小集成測試。

有趣的是，如果我在測試中注釋掉@RunWith注釋，那么測試就會正確通過。 顯然我不需要@RunWith注釋來進行這種減少測試，但真正的測試相當廣泛地使用了模擬，所以我寧願不必使用PowerMock。

package com.example;

import org.apache.spark.SparkConf;
import org.apache.spark.streaming.Duration;
import org.apache.spark.streaming.api.java.JavaStreamingContext;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.modules.junit4.PowerMockRunner;

@RunWith(PowerMockRunner.class)
public class SampleTest {

    @Before
    public void setup() throws Exception {
        SparkConf conf = new     SparkConf(false).setMaster("local[2]").setAppName("My app");
        JavaStreamingContext jsc = new JavaStreamingContext(conf, new Duration(1000));
    }

    @Test
    public void exampleTest() {
    }
}

以下是我看到的例外情況

java.io.IOException: failure to login
    at org.apache.hadoop.security.UserGroupInformation.loginUserFromSubject(UserGroupInformation.java:796)
    at org.apache.hadoop.security.UserGroupInformation.getLoginUser(UserGroupInformation.java:748)
    at org.apache.hadoop.security.UserGroupInformation.getCurrentUser(UserGroupInformation.java:621)
    at org.apache.spark.util.Utils$$anonfun$getCurrentUserName$1.apply(Utils.scala:2162)
    at org.apache.spark.util.Utils$$anonfun$getCurrentUserName$1.apply(Utils.scala:2162)
    at scala.Option.getOrElse(Option.scala:120)
    at org.apache.spark.util.Utils$.getCurrentUserName(Utils.scala:2162)
    at org.apache.spark.SparkContext.<init>(SparkContext.scala:301)
    at org.apache.spark.streaming.StreamingContext$.createNewSparkContext(StreamingContext.scala:842)
    at org.apache.spark.streaming.StreamingContext.<init>(StreamingContext.scala:80)
    at org.apache.spark.streaming.api.java.JavaStreamingContext.<init>(JavaStreamingContext.scala:133)
    at com.example.SampleTest.setup(SampleTest.java:19)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.junit.internal.runners.MethodRoadie.runBefores(MethodRoadie.java:133)
    at org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters(MethodRoadie.java:96)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.executeTest(PowerMockJUnit44RunnerDelegateImpl.java:294)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTestInSuper(PowerMockJUnit47RunnerDelegateImpl.java:127)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTest(PowerMockJUnit47RunnerDelegateImpl.java:82)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runBeforesThenTestThenAfters(PowerMockJUnit44RunnerDelegateImpl.java:282)
    at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:87)
    at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:50)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.invokeTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:207)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.runMethods(PowerMockJUnit44RunnerDelegateImpl.java:146)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$1.run(PowerMockJUnit44RunnerDelegateImpl.java:120)
    at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:34)
    at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:44)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.run(PowerMockJUnit44RunnerDelegateImpl.java:122)
    at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.run(JUnit4TestSuiteChunkerImpl.java:106)
    at org.powermock.modules.junit4.common.internal.impl.AbstractCommonPowerMockRunner.run(AbstractCommonPowerMockRunner.java:53)
    at org.powermock.modules.junit4.PowerMockRunner.run(PowerMockRunner.java:59)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: javax.security.auth.login.LoginException: Can't find user name
    at org.apache.hadoop.security.UserGroupInformation$HadoopLoginModule.commit(UserGroupInformation.java:197)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at javax.security.auth.login.LoginContext.invoke(LoginContext.java:784)
    at javax.security.auth.login.LoginContext.access$000(LoginContext.java:203)
    at javax.security.auth.login.LoginContext$5.run(LoginContext.java:721)
    at javax.security.auth.login.LoginContext$5.run(LoginContext.java:719)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.login.LoginContext.invokeCreatorPriv(LoginContext.java:718)
    at javax.security.auth.login.LoginContext.login(LoginContext.java:591)
    at org.apache.hadoop.security.UserGroupInformation.loginUserFromSubject(UserGroupInformation.java:771)
    ... 38 more

各種依賴項的版本如下所示

• hadoop-client 2.6
• apache spark 1.4.0 / 1.4.1
• junit 4.12
• 輕松模擬3.31
• power mock 1.6.2

我已經嘗試過各種版本的Spark。 上面的測試通過了以下版本的Spark

• 1.1.1
• 1.2.2

它從Spark 1.3.0開始失敗。

有什么想法我需要改變才能讓它發揮作用？

Answer 1

查看SparkContext的源代碼，該行在嘗試獲取當前用戶名時導致異常。 在版本1.2中有一個回退默認SparkContext.SPARK_UNKNOWN_USER並且它不需要當前登錄用戶：

 // Set SPARK_USER for user who is running SparkContext.
 val sparkUser = Option {
     Option(System.getenv("SPARK_USER")).getOrElse(System.getProperty("user.name"))
  }.getOrElse {
      SparkContext.SPARK_UNKNOWN_USER
  }

版本1.3中引入的此代碼不再具有默認用戶，因此您不會在早期版本中出現此錯誤：

// Set SPARK_USER for user who is running SparkContext.
val sparkUser = Utils.getCurrentUserName()

這將在Utils調用以下代碼 ：

/**
   * Returns the current user name. This is the currently logged in user, unless that's been
   * overridden by the `SPARK_USER` environment variable.
   */
  def getCurrentUserName(): String = {
    Option(System.getenv("SPARK_USER"))
      .getOrElse(UserGroupInformation.getCurrentUser().getShortUserName())
  }

如果設置環境變量SPARK_USER ，則應該能夠阻止分支到UserGroupInformation，從而導致異常。

UserGroupInformation是一個Hadoop Security類，看起來使用PowerMock阻止它正常工作。