尝试启动 mapReduce 作业"ImportError: Could not find 'input_readers' on path 'map reduce'"出错

Question

我得到这个错误…当试图通过http://localhost:8080/mapreduce启动器页面运行我的mapreduce作业时，" importterror:无法在路径'map reduce'上找到'input_readers' "。

看起来我的问题类似于这篇文章，AppEngine mapper API导入错误。不幸的是，没有给出明确的答案。

我已经把它简化成这个小小的testmapreduce.py:

from google.appengine.ext import db
class TestEntity(db.Model):
    value = db.StringProperty()
def mapperhandler(test):
    print test.value
    return

和mapreduce。yaml:

mapreduce:
- name: Simplest MapReduce
  mapper:
    handler: testmapreduce.mapperhandler
    input_reader: mapreduce.input_readers.DatastoreInputReader
    params:
    - name: entity_kind
      default: testmapreduce.TestEntity

一个可能的线索是__init__.py的存在没有影响(无论是在项目根目录、mapreduce目录还是两者中)。我确信我犯了一个初学者的错误，但在过去的几天里，我已经阅读了所有的文档，以及我能找到的所有示例。谢谢。

更新:我得到同样的错误，试图调用它通过…

control.start_map(
   "Give awards",
   "testmapreduce.mapperhandler",
   "mapreduce.input_readers.DatastoreInputReader",
   {"entity_kind": "testmapreduce.TestEntity"},
   shard_count=10)

更新:按照要求，堆栈跟踪——让我知道还有什么有用的…

ERROR    2011-10-16 17:09:27,216 _webapp25.py:464] Could not find 'input_readers' on path 'mapreduce'
Traceback (most recent call last):
 File "/Develop/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/webapp/_webapp25.py", line 701, in __call__
   handler.get(*groups)
 File "/Users/lc/PycharmProjects/mrtest/testmapreduce.py", line 22, in get
   shard_count=10)      # handle web form test interface
 File "/Users/lc/PycharmProjects/mrtest/mapreduce/control.py", line 94, in start_map
   transactional=transactional)
 File "/Users/lc/PycharmProjects/mrtest/mapreduce/handlers.py", line 811, in _start_map
   mapper_input_reader_class = mapper_spec.input_reader_class()
 File "/Users/lc/PycharmProjects/mrtest/mapreduce/model.py", line 393, in input_reader_class
   return util.for_name(self.input_reader_spec)
 File "/Users/lc/PycharmProjects/mrtest/mapreduce/util.py", line 94, in for_name
   module = for_name(module_name, recursive=True)
 File "/Users/lc/PycharmProjects/mrtest/mapreduce/util.py", line 102, in for_name
   short_name, module_name))
ImportError: Could not find 'input_readers' on path 'mapreduce'
INFO     2011-10-16 22:09:27,253 dev_appserver.py:4247] "GET /giveawards HTTP/1.1" 500 -

Answer 1

这个问题原来是我在本地环境中使用了2.7版本的Python解释器。当我切换到2.5时，它工作得很好