Change streaming code to use new mapreduce api.
-----------------------------------------------
Key: MAPREDUCE-3619
URL: https://issues.apache.org/jira/browse/MAPREDUCE-3619
Project: Hadoop Map/Reduce
Issue Type: Improvement
Components: contrib/streaming
Affects Versions: 0.23.1
Reporter: Liyin Liang
If we run a streaming job with following python script as mapper or reducer,
the job will throws NullPointerException.
{code:}
#!/usr/bin/python
import sys,os
class MyTask:
def __init__(self, file=sys.stdin):
self.file = file
print >>sys.stderr, "reporter:counter:spam,disp_flag_record,0"
print >>sys.stderr, "reporter:counter:spam,spam_record,0"
def process(self):
while True:
line = self.file.readline()
if not line:
break;
print line
if __name__ == "__main__":
task = MyTask()
task.process()
{code}
Here is the NPE related log:
2011-12-22 14:14:06,310 WARN org.apache.hadoop.streaming.PipeMapRed:
java.lang.NullPointerException
at
org.apache.hadoop.streaming.PipeMapRed$MRErrorThread.incrCounter(PipeMapRed.java:502)
at
org.apache.hadoop.streaming.PipeMapRed$MRErrorThread.run(PipeMapRed.java:444)
This is because the above script's "print >>sys.stderr" will invoke
reporter.incrCounter() during PipeMapper|PipeReducer.configure(). While we can
not get reporter in configure() function.
To fix this problem, we should change streaming code to use new-api. Then we
can call context.getCounter() in Mapper|Reducer.setup() function.
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