python – ndb.get_multi返回AssertionError
作者：互联网
在过去48小时左右,我的小python GAE应用程序已经开始从ndb.get_multi调用获取AssertionErrors.
将附加完整的回溯,并且在/base/data/…/ndb/model.py的第734行的_BaseValue的__init__中生成服务器上生成错误,并且失败的断言是b_val不是None,并带有消息“Can not not包装无“
该错误似乎与特定实体或实体无关,但到目前为止我只看到过一种实体类型(尚未测试其他实体).
get_multi调用仅适用于十几个键,并且错误是间歇性的,因此重复它有时会成功.或不…
我没有通过远程shell看到这个错误,但我注意到我的本地安装是1.9.23,而日志条目说生产服务器是1.9.25(GoogleAppEngineLauncher说我的本地安装是最新的)
我正在添加一个解决方法来捕获异常并遍历密钥以单独获取它们但我仍然在context.py的第744行看到有关“暂停的生成器获取”的上游警告.
对于至少2个不同的键列表(以及AssertionError之前),警告会在列表中首次获取此实体类型时出现.
我不想以这种方式包装所有get_multi调用.
这是怎么回事？
追溯：
Cannot wrap None
Traceback (most recent call last):
File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/webapp2-2.5.2/webapp2.py", line 570, in dispatch
return method(*args, **kwargs)
File "/base/data/home/apps/s~thegapnetball/115.386356111937586421/handlers/assess.py", line 50, in get
rs = ndb.get_multi(t.players)
File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/ext/ndb/model.py", line 3905, in get_multi
for future in get_multi_async(keys, **ctx_options)]
File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/ext/ndb/tasklets.py", line 326, in get_result
self.check_success()
File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/ext/ndb/tasklets.py", line 372, in _help_tasklet_along
value = gen.send(val)
File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/ext/ndb/context.py", line 751, in get
pbs = entity._to_pb(set_key=False).SerializePartialToString()
File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/ext/ndb/model.py", line 3147, in _to_pb
prop._serialize(self, pb, projection=self._projection)
File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/ext/ndb/model.py", line 2379, in _serialize
projection=projection)
File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/ext/ndb/model.py", line 1405, in _serialize
values = self._get_base_value_unwrapped_as_list(entity)
File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/ext/ndb/model.py", line 1175, in _get_base_value_unwrapped_as_list
wrapped = self._get_base_value(entity)
File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/ext/ndb/model.py", line 1163, in _get_base_value
return self._apply_to_values(entity, self._opt_call_to_base_type)
File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/ext/ndb/model.py", line 1335, in _apply_to_values
value[:] = map(function, value)
File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/ext/ndb/model.py", line 1217, in _opt_call_to_base_type
value = _BaseValue(self._call_to_base_type(value))
File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/ext/ndb/model.py", line 734, in \__init__
assert b_val is not None, "Cannot wrap None"
AssertionError: Cannot wrap None
解决方法:
Tim Hoffman和Patrick Costello让我走上正确的道路来解决这个问题.
我增加版本以保护一些更改,但花费的时间比我预期的要长.
一个更改将重复的StructuredProperty添加到从ndb.Model派生的模型中,并且我将多个实体与额外属性(总共1100个中的约30个)放在一起.
没有额外属性的先前版本仍然是默认值并且被轻易使用,因此实体变得刚刚不足以产生间歇性AssertionError.
主要教训是注意Google架构更新文章中的建议,特别是将基础父级更改为Expando和/或禁用数据存储区编辑,直到完成任何迁移.
https://cloud.google.com/appengine/articles/update_schema
修复是将属性添加到以前的版本,获取所有实体,然后将它们放入.
谢谢蒂姆和帕特里克的指针！
标签：app-engine-ndb,python,python-2-7,google-app-engine,google-cloud-datastore 来源： https://codeday.me/bug/20190824/1708653.html