Pig 通过带有导入模块的 python 脚本进行流式传输

Question

使用 Pigtmp$ pig --version Apache Pig 版本 0.8.1-cdh3u1（重新导出） 编译于 2011 年 7 月 18 日，08:29:40

我有一个 python 脚本 (c-python)，它导入另一个脚本，在我的示例中都非常简单：

DATA example$ hadoop fs -cat /user/pavel/trivial.log

1   one
2   two
3   three

不包含示例 - 工作正常

example$ pig -f trivial_stream.pig

(1,1,one)
()
(1,2,two)
()
(1,3,three)
()

其中 1) trivial_stream.pig:

DEFINE test_stream `test_stream.py` SHIP ('test_stream.py');
A = LOAD 'trivial.log' USING PigStorage('\t') AS (mynum: int, mynumstr: chararray);
C = STREAM A THROUGH test_stream;
DUMP C;

2) test_stream.py

#! /usr/bin/env python

import sys
import string

for line in sys.stdin:
    if len(line) == 0: continue
    new_line = line
    print "%d\t%s" % (1, new_line) 

所以本质上我只是用一个键聚合行，没什么特别的。

示例包括 - 炸弹！ 现在我想从 python 导入模块附加一个字符串，该模块与 test_stream.py 位于同一目录中。我尝试以多种不同的方式发送导入模块，但得到相同的错误（见下文）

1）trivial_stream.pig：

DEFINE test_stream `test_stream.py` SHIP ('test_stream.py', 'test_import.py');
A = LOAD 'trivial.log' USING PigStorage('\t') AS (mynum: int, mynumstr: chararray);
C = STREAM A THROUGH test_stream;
DUMP C;

2）test_stream.py

#! /usr/bin/env python

import sys
import string

import test_import

for line in sys.stdin:
    if len(line) == 0: continue
    new_line = ("%s-%s") % (line.strip(), test_import.getTestLine())
    print "%d\t%s" % (1, new_line) 

3）test_import.py

def getTestLine():
    return "test line";

现在

example$ pig -f trivial_stream.pig

后端错误消息

org.apache.pig.backend.executionengine.ExecException: ERROR 2055: Received Error while processing the map plan: 'test_stream.py ' failed with exit status: 1
    at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapBase.runPipeline(PigMapBase.java:265)
    at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapBase.cleanup(PigMapBase.java:103)
    at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:146)
    at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:647)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:323)
    at org.apache.hadoop.mapred.Child$4.run(Child.java:270)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:396)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1127)
    at org.apache.hadoop.mapred.Child.main(Child.java:264)

Pig Stack Trace

ERROR 2997: Unable to recreate exception from backed error: org.apache.pig.backend.executionengine.ExecException: ERROR 2055: Received Error while processing the map plan: 'test_stream.py ' failed with exit status: 1

org.apache.pig.impl.logicalLayer.FrontendException: ERROR 1066: Unable to open iterator for alias C. Backend error : Unable to recreate exception from backed error: org.apache.pig.backend.executionengine.ExecException: ERROR 2055: Received Error while processing the map plan: 'test_stream.py ' failed with exit status: 1
    at org.apache.pig.PigServer.openIterator(PigServer.java:753)
    at org.apache.pig.tools.grunt.GruntParser.processDump(GruntParser.java:615)
    at org.apache.pig.tools.pigscript.parser.PigScriptParser.parse(PigScriptParser.java:303)
    at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:168)
    at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:144)
    at org.apache.pig.tools.grunt.Grunt.exec(Grunt.java:90)
    at org.apache.pig.Main.run(Main.java:396)
    at org.apache.pig.Main.main(Main.java:107)
Caused by: org.apache.pig.backend.executionengine.ExecException: ERROR 2997: Unable to recreate exception from backed error: org.apache.pig.backend.executionengine.ExecException: ERROR 2055: Received Error while processing the map plan: 'test_stream.py ' failed with exit status: 1
    at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.Launcher.getErrorMessages(Launcher.java:221)
    at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.Launcher.getStats(Launcher.java:151)
    at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher.launchPig(MapReduceLauncher.java:337)
    at org.apache.pig.backend.hadoop.executionengine.HExecutionEngine.execute(HExecutionEngine.java:382)
    at org.apache.pig.PigServer.executeCompiledLogicalPlan(PigServer.java:1209)
    at org.apache.pig.PigServer.storeEx(PigServer.java:885)
    at org.apache.pig.PigServer.store(PigServer.java:827)
    at org.apache.pig.PigServer.openIterator(PigServer.java:739)
    ... 7 more

非常感谢您的帮助！ -帕维尔

Answer 1

上面评论的正确答案：

依赖项没有被发布，如果你希望你的Python应用程序与pig一起工作，你需要tar它（不要忘记init.py！），然后将.tar文件包含在pig的SHIP语句中。您要做的第一件事就是解压该应用程序。路径可能存在问题，因此我建议在 tar 提取之前进行以下操作：sys.path.insert(0, os.getcwd())。

Answer 2

您需要将当前目录附加到 test_stream.py 中的 sys.path 中：

#! /usr/bin/env python

import sys
sys.path.append(".")

因此，您在那里使用的 SHIP 命令确实会传送 python 脚本，但您只需要告诉Python 去哪里找。