使用Git下载Hadoop的到本地Eclipse开发环境

使用Git下载Hadoop的到本地Eclipse开发环境

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• Hadoop
• *n*x
• MacBook Air

hadoopgitmaveneclipsejava 

问题场景 
按照官网http://wiki.apache.org/hadoop/EclipseEnvironment指导，要把Hadoop下载到本地，并构建Eclipse开发环境，只需要三条指令：

1. $ git clone git://git.apache.org/hadoop-common.git
2. $ mvn install -DskipTests
3. $ mvn eclipse:eclipse -DdownloadSources=true -DdownloadJavadocs=true

即可，但当我在本地执行完第二条后，报出如下错误日志信息：

1. [INFO]
2. [INFO] --- maven-antrun-plugin:1.6:run (compile-proto) @ hadoop-common ---
3. [INFO] Executing tasks
4. main:
5. [exec] target/compile-proto.sh: line 17: protoc: command not found
6. [exec] target/compile-proto.sh: line 17: protoc: command not found
7. [INFO] ------------------------------------------------------------------------
8. [INFO] Reactor Summary:
9. [INFO]
10. [INFO] Apache Hadoop Main ................................ SUCCESS [2.389s]
11. [INFO] Apache Hadoop Project POM ......................... SUCCESS [0.698s]
12. [INFO] Apache Hadoop Annotations ......................... SUCCESS [1.761s]
13. [INFO] Apache Hadoop Project Dist POM .................... SUCCESS [0.729s]
14. [INFO] Apache Hadoop Assemblies .......................... SUCCESS [0.353s]
15. [INFO] Apache Hadoop Auth ................................ SUCCESS [1.998s]
16. [INFO] Apache Hadoop Auth Examples ....................... SUCCESS [1.227s]
17. [INFO] Apache Hadoop Common .............................. FAILURE [1.132s]
18. [INFO] Apache Hadoop Common Project ...................... SKIPPED
19. [INFO] Apache Hadoop HDFS ................................ SKIPPED
20. [INFO] Apache Hadoop HttpFS .............................. SKIPPED
21. [INFO] Apache Hadoop HDFS BookKeeper Journal ............. SKIPPED
22. [INFO] Apache Hadoop HDFS Project ........................ SKIPPED
23. [INFO] hadoop-yarn ....................................... SKIPPED
24. [INFO] hadoop-yarn-api ................................... SKIPPED
25. [INFO] hadoop-yarn-common ................................ SKIPPED
26. [INFO] hadoop-yarn-server ................................ SKIPPED
27. [INFO] hadoop-yarn-server-common ......................... SKIPPED
28. [INFO] hadoop-yarn-server-nodemanager .................... SKIPPED
29. [INFO] hadoop-yarn-server-web-proxy ...................... SKIPPED
30. [INFO] hadoop-yarn-server-resourcemanager ................ SKIPPED
31. [INFO] hadoop-yarn-server-tests .......................... SKIPPED
32. [INFO] hadoop-mapreduce-client ........................... SKIPPED
33. [INFO] hadoop-mapreduce-client-core ...................... SKIPPED
34. [INFO] hadoop-yarn-applications .......................... SKIPPED
35. [INFO] hadoop-yarn-applications-distributedshell ......... SKIPPED
36. [INFO] hadoop-yarn-site .................................. SKIPPED
37. [INFO] hadoop-mapreduce-client-common .................... SKIPPED
38. [INFO] hadoop-mapreduce-client-shuffle ................... SKIPPED
39. [INFO] hadoop-mapreduce-client-app ....................... SKIPPED
40. [INFO] hadoop-mapreduce-client-hs ........................ SKIPPED
41. [INFO] hadoop-mapreduce-client-jobclient ................. SKIPPED
42. [INFO] Apache Hadoop MapReduce Examples .................. SKIPPED
43. [INFO] hadoop-mapreduce .................................. SKIPPED
44. [INFO] Apache Hadoop MapReduce Streaming ................. SKIPPED
45. [INFO] Apache Hadoop Distributed Copy .................... SKIPPED
46. [INFO] Apache Hadoop Archives ............................ SKIPPED
47. [INFO] Apache Hadoop Rumen ............................... SKIPPED
48. [INFO] Apache Hadoop Extras .............................. SKIPPED
49. [INFO] Apache Hadoop Tools Dist .......................... SKIPPED
50. [INFO] Apache Hadoop Tools ............................... SKIPPED
51. [INFO] Apache Hadoop Distribution ........................ SKIPPED
52. [INFO] ------------------------------------------------------------------------
53. [INFO] BUILD FAILURE
54. [INFO] ------------------------------------------------------------------------
55. [INFO] Total time: 12.483s
56. [INFO] Finished at: Mon Jan 30 22:57:23 GMT+08:00 2012
57. [INFO] Final Memory: 24M/81M
58. [INFO] ------------------------------------------------------------------------
59. [ERROR] Failed to execute goal org.apache.maven.plugins:maven-antrun-plugin:1.6:run (compile-proto) on project hadoop-common: An Ant BuildException has occured: exec returned: 127 -> [Help 1]
60. [ERROR]
61. [ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
62. [ERROR] Re-run Maven using the -X switch to enable full debug logging.
63. [ERROR]
64. [ERROR] For more information about the errors and possible solutions, please read the following articles:
65. [ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
66. [ERROR]
67. [ERROR] After correcting the problems, you can resume the build with the command
68. [ERROR]   mvn <goals> -rf :hadoop-common

此问题我暂时还未分析具体原因和解决方案，暂时记录下。 
展开分析 
通过再此使用命令打出错误信息：

1. $ mvn install -DskipTests -e

得到详细错误信息为：

1. [INFO] ------------------------------------------------------------------------
2. [INFO] BUILD FAILURE
3. [INFO] ------------------------------------------------------------------------
4. [INFO] Total time: 9.387s
5. [INFO] Finished at: Mon Jan 30 23:11:07 GMT+08:00 2012
6. [INFO] Final Memory: 19M/81M
7. [INFO] ------------------------------------------------------------------------
8. [ERROR] Failed to execute goal org.apache.maven.plugins:maven-antrun-plugin:1.6:run (compile-proto) on project hadoop-common: An Ant BuildException has occured: exec returned: 127 -> [Help 1]
9. org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-antrun-plugin:1.6:run (compile-proto) on project hadoop-common: An Ant BuildException has occured: exec returned: 127
10. at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:217)
11. at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
12. at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
13. at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)
14. at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
15. at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
16. at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
17. at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:319)
18. at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
19. at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
20. at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
21. at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
22. at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
23. at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
24. at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
25. at java.lang.reflect.Method.invoke(Method.java:597)
26. at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
27. at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
28. at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
29. at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)
30. Caused by: org.apache.maven.plugin.MojoExecutionException: An Ant BuildException has occured: exec returned: 127
31. at org.apache.maven.plugin.antrun.AntRunMojo.execute(AntRunMojo.java:283)
32. at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101)
33. at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
34. ... 19 more
35. Caused by: /Users/apple/Documents/Hadoop-common-dev/hadoop-common/hadoop-common-project/hadoop-common/target/antrun/build-main.xml:23: exec returned: 127
36. at org.apache.tools.ant.taskdefs.ExecTask.runExecute(ExecTask.java:650)
37. at org.apache.tools.ant.taskdefs.ExecTask.runExec(ExecTask.java:676)
38. at org.apache.tools.ant.taskdefs.ExecTask.execute(ExecTask.java:502)
39. at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:291)
40. at sun.reflect.GeneratedMethodAccessor16.invoke(Unknown Source)
41. at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
42. at java.lang.reflect.Method.invoke(Method.java:597)
43. at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
44. at org.apache.tools.ant.Task.perform(Task.java:348)
45. at org.apache.tools.ant.Target.execute(Target.java:390)
46. at org.apache.tools.ant.Target.performTasks(Target.java:411)
47. at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1397)
48. at org.apache.tools.ant.Project.executeTarget(Project.java:1366)
49. at org.apache.maven.plugin.antrun.AntRunMojo.execute(AntRunMojo.java:270)
50. ... 21 more
51. [ERROR]
52. [ERROR] Re-run Maven using the -X switch to enable full debug logging.
53. [ERROR]
54. [ERROR] For more information about the errors and possible solutions, please read the following articles:
55. [ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
56. [ERROR]

通过上面错误信息，真方便找到解决方案。

根据上面的提示，访问https://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException 
得到如下提示信息： 
        Unlike many other errors, this exception is not generated by the Maven core itself but by a plugin. As a rule of thumb, plugins use this error to signal a problem in their configuration or the information they retrieved from the POM. 
        这里说的意思是： 
        这个错误不是Maven本身的错误，根据经验，可能是Maven使用的插件通过这个异常来标识它们没有从POM中获得相关的配置信息。

接下来进一步分析，通过Maven构建Hadoop过程中是否使用了插件。 
        从错误日志分析，编译过程使用了插件：maven-antrun-plugin。由于编译Hadoop-common过程中出错，所以进一步定位到hadoop-common工程下的POM.xml，可到看到下面信息：

1. <plugin>
2. <groupId>org.apache.maven.plugins</groupId>
3. <artifactId>maven-antrun-plugin</artifactId>
4. <executions>
5. <execution>
6. <id>compile-proto</id>
7. <phase>generate-sources</phase>
8. <goals>
9. <goal>run</goal>
10. </goals>
11. <configuration>
12. <target>
13. <echo file="target/compile-proto.sh">
14. PROTO_DIR=src/main/proto
15. JAVA_DIR=target/generated-sources/java
16. which cygpath 2> /dev/null
17. if [ $? = 1 ]; then
18. IS_WIN=false
19. else
20. IS_WIN=true
21. WIN_PROTO_DIR=`cygpath --windows $PROTO_DIR`
22. WIN_JAVA_DIR=`cygpath --windows $JAVA_DIR`
23. fi
24. mkdir -p $JAVA_DIR 2> /dev/null
25. for PROTO_FILE in `ls $PROTO_DIR/*.proto 2> /dev/null`
26. do
27. if [ "$IS_WIN" = "true" ]; then
28. protoc -I$WIN_PROTO_DIR --java_out=$WIN_JAVA_DIR $PROTO_FILE
29. else
30. protoc -I$PROTO_DIR --java_out=$JAVA_DIR $PROTO_FILE
31. fi
32. done
33. </echo>
34. <exec executable="sh" dir="${basedir}" failonerror="true">
35. <arg line="target/compile-proto.sh"/>
36. </exec>
37. </target>
38. </configuration>
39. </execution>
40. <execution>
41. <id>compile-test-proto</id>
42. <phase>generate-test-sources</phase>
43. <goals>
44. <goal>run</goal>
45. </goals>
46. <configuration>
47. <target>
48. <echo file="target/compile-test-proto.sh">
49. PROTO_DIR=src/test/proto
50. JAVA_DIR=target/generated-test-sources/java
51. which cygpath 2> /dev/null
52. if [ $? = 1 ]; then
53. IS_WIN=false
54. else
55. IS_WIN=true
56. WIN_PROTO_DIR=`cygpath --windows $PROTO_DIR`
57. WIN_JAVA_DIR=`cygpath --windows $JAVA_DIR`
58. fi
59. mkdir -p $JAVA_DIR 2> /dev/null
60. for PROTO_FILE in `ls $PROTO_DIR/*.proto 2> /dev/null`
61. do
62. if [ "$IS_WIN" = "true" ]; then
63. protoc -I$WIN_PROTO_DIR --java_out=$WIN_JAVA_DIR $PROTO_FILE
64. else
65. protoc -I$PROTO_DIR --java_out=$JAVA_DIR $PROTO_FILE
66. fi
67. done
68. </echo>
69. <exec executable="sh" dir="${basedir}" failonerror="true">
70. <arg line="target/compile-test-proto.sh"/>
71. </exec>
72. </target>
73. </configuration>
74. </execution>
75. <execution>
76. <id>save-version</id>
77. <phase>generate-sources</phase>
78. <goals>
79. <goal>run</goal>
80. </goals>
81. <configuration>
82. <target>
83. <mkdir dir="${project.build.directory}/generated-sources/java"/>
84. <exec executable="sh">
85. <arg
86. line="${basedir}/dev-support/saveVersion.sh ${project.version} ${project.build.directory}/generated-sources/java"/>
87. </exec>
88. </target>
89. </configuration>
90. </execution>
91. <execution>
92. <id>generate-test-sources</id>
93. <phase>generate-test-sources</phase>
94. <goals>
95. <goal>run</goal>
96. </goals>
97. <configuration>
98. <target>
99. <mkdir dir="${project.build.directory}/generated-test-sources/java"/>
100. <taskdef name="recordcc" classname="org.apache.hadoop.record.compiler.ant.RccTask">
101. <classpath refid="maven.compile.classpath"/>
102. </taskdef>
103. <recordcc destdir="${project.build.directory}/generated-test-sources/java">
104. <fileset dir="${basedir}/src/test/ddl" includes="**/*.jr"/>
105. </recordcc>
106. </target>
107. </configuration>
108. </execution>
109. <execution>
110. <id>create-log-dir</id>
111. <phase>process-test-resources</phase>
112. <goals>
113. <goal>run</goal>
114. </goals>
115. <configuration>
116. <target>
117. <!--
118. TODO: there are tests (TestLocalFileSystem#testCopy) that fail if data
119. TODO: from a previous run is present
120. -->
121. <delete dir="${test.build.data}"/>
122. <mkdir dir="${test.build.data}"/>
123. <mkdir dir="${hadoop.log.dir}"/>
124. <copy toDir="${project.build.directory}/test-classes">
125. <fileset dir="${basedir}/src/main/conf"/>
126. </copy>
127. </target>
128. </configuration>
129. </execution>
130. <execution>
131. <phase>pre-site</phase>
132. <goals>
133. <goal>run</goal>
134. </goals>
135. <configuration>
136. <tasks>
137. <copy file="src/main/resources/core-default.xml" todir="src/site/resources"/>
138. <copy file="src/main/xsl/configuration.xsl" todir="src/site/resources"/>
139. </tasks>
140. </configuration>
141. </execution>
142. </executions>
143. </plugin>

上面是在Pom.xml文件中使用Maven下使用Ant插件，里面有一行：

1. <echo file="target/compile-proto.sh">

看着让人不解，联系到HowToContribueToHadoop的文章http://wiki.apache.org/hadoop/HowToContribute可以推知，有可能由于本地没有安装ProtocolBuffers引起的，因为文章内部特别说明了：

引用

Hadoop 0.23+ must have Google's ProtocolBuffers for compilation to work.

接下来打算在本地重新安装ProtocolBuffers后再编译部署。

如预期，在本地安装好了Protoc Buffer后，后面两条指令顺利执行完整，剩下的就依据官网把目录下的工程导入Eclipse后，就可以在Eclipse下学习调试源码。