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Hadoop 执行 Python 代码的权限问题

tag-icon • tag-icon 14.04 permissions python hadoop
Hadoop 执行 Python 代码的权限问题

我已经安装了 hadoop-1.0.3，并在 14.04 中成功执行了一个示例程序 wordcount，如下所示此链接。

我尝试按照以下方法用 Python 编写程序这里。

我复制了以下代码，

#!/usr/bin/env python

import sys

# input comes from STDIN (standard input)
for line in sys.stdin:
    # remove leading and trailing whitespace
    line = line.strip()
    # split the line into words
    words = line.split()
    # increase counters
    for word in words:
        # write the results to STDOUT (standard output);
        # what we output here will be the input for the
        # Reduce step, i.e. the input for reducer.py
        #
        # tab-delimited; the trivial word count is 1
        print '%s\t%s' % (word, 1)

粘贴到文本编辑器并将文件另存为，

/home/hadoop用户/mapper.py

注：我的hadoop用户名是hadoopuser

并获得许可，

hadoopuser@arul-PC:~$ sudo chmod +X /home/hadoopuser/mapper.py

并将以下代码保存到/home/hadoopuser/reducer.py

#!/usr/bin/env python

from operator import itemgetter
import sys

current_word = None
current_count = 0
word = None

# input comes from STDIN
for line in sys.stdin:
# remove leading and trailing whitespace
line = line.strip()

# parse the input we got from mapper.py
word, count = line.split('\t', 1)

# convert count (currently a string) to int
try:
    count = int(count)
except ValueError:
    # count was not a number, so silently
    # ignore/discard this line
    continue

# this IF-switch only works because Hadoop sorts map output
# by key (here: word) before it is passed to the reducer
if current_word == word:
    current_count += count
else:
    if current_word:
        # write result to STDOUT
        print '%s\t%s' % (current_word, current_count)
    current_count = count
    current_word = word

# do not forget to output the last word if needed!
if current_word == word:
print '%s\t%s' % (current_word, current_count)

因此，获得执行许可，

hadoopuser@arul-PC:~$ sudo chmod +X /home/hadoopuser/reducer.py

当我尝试的时候，

hadoopuser@arul-PC:~$ echo "AAA ACC ABC AAA AAA  ADD arul " | /home/hadoopuser/mapper.py

我得到的答复是，

-su: /home/hadoopuser/mapper.py: Permission denied

我也尝试过，但sudo得到的答复相同。请给我一个解决方案。

答案1

首先必须通过在终端中输入以下命令来设置主路径，

export PATH=$PATH:/home/hadoopuser/

然后获得使用许可，

chmod 755 /home/hadoopuser/mapper.py
chmod 755 /home/hadoopuser/reducer.py

并得到如下结果：

echo "arul sijo sijo tijo tijo tijo sijo arul tijo" | /home/hadoopuser/mapper.py | sort -k1,1 | /home/hadoopuser/reducer.py
arul    2
sijo    3
tijo    4

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