your stack trace shows a different event hook that's causing the problem.
codebase/database/__init__.py, so you want to move that event to
before_mapper_configured:
> File "/codebase_mountpoint/codebase/database/__init__.py", line 177, in
> set_serialize_map
> for c in visible_table_columns:
> File "/codebase_mountpoint/codebase/database/__init__.py", line 175, in
> <lambda>
> lambda x: cls.get_property_name_from_column(x) not in negatives,
> File "/codebase_mountpoint/codebase/database/__init__.py", line 106, in
> get_property_name_from_column
> return sqlalchemy.inspect(cls).get_property_by_column(column_obj).key
On Sat, Oct 9, 2021, at 11:53 PM, niuji...@gmail.com wrote:
> Thank you Mike! My event-hooking code is like this:
>
> @sqlalchemy.event.listens_for(_MyBase, "class_instrument")
> def set_serialize_map(cls):
> module_logger.info(
> f"<set_serialize_map> for {cls.__name__} is just invoked!")
> ...
>
>
>
> Here is the stack trace:
>
> 2021-10-10 03:47:34 AM database MainThread 140107141936960 INFO
> <set_serialize_map> for GeoAreaVariantName is just invoked!
> Traceback (most recent call last):
> File "main.py", line 101, in <module>
> cherrypy.quickstart(root=HomePage_Server(),
> File "main.py", line 50, in __init__
> self._collect_subunit_servers()
> File "main.py", line 73, in _collect_subunit_servers
> unit_server = importlib.import_module(
> File "/usr/lib/python3.8/importlib/__init__.py", line 127, in import_module
> return _bootstrap._gcd_import(name[level:], package, level)
> File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
> File "<frozen importlib._bootstrap>", line 991, in _find_and_load
> File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
> File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
> File "<frozen importlib._bootstrap_external>", line 848, in exec_module
> File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
> File "/codebase_mountpoint/codebase/geography_server.py", line 14, in
> <module>
> from database.geography_schema import *
> File "/codebase_mountpoint/codebase/database/geography_schema.py", line 19,
> in <module>
> class GeoArea(my_mixins.HasVariantName_Mixin, dal.Base):
> File "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/decl_api.py",
> line 72, in __init__
> _as_declarative(reg, cls, dict_)
> File "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/decl_base.py",
> line 126, in _as_declarative
> return _MapperConfig.setup_mapping(registry, cls, dict_, None, {})
> File "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/decl_base.py",
> line 177, in setup_mapping
> return cfg_cls(registry, cls_, dict_, table, mapper_kw)
> File "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/decl_base.py",
> line 299, in __init__
> self._scan_attributes()
> File "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/decl_base.py",
> line 557, in _scan_attributes
> ret = getattr(cls, name)
> File "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/decl_api.py",
> line 237, in __get__
> reg[desc] = obj = desc.fget(cls)
> File "/codebase_mountpoint/codebase/database/my_mixins.py", line 39, in
> variant_names
> cls.VariantName = type(
> File "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/decl_api.py",
> line 72, in __init__
> _as_declarative(reg, cls, dict_)
> File "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/decl_base.py",
> line 126, in _as_declarative
> return _MapperConfig.setup_mapping(registry, cls, dict_, None, {})
> File "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/decl_base.py",
> line 177, in setup_mapping
> return cfg_cls(registry, cls_, dict_, table, mapper_kw)
> File "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/decl_base.py",
> line 314, in __init__
> self._early_mapping(mapper_kw)
> File "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/decl_base.py",
> line 200, in _early_mapping
> self.map(mapper_kw)
> File "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/decl_base.py",
> line 992, in map
> mapper_cls(self.cls, self.local_table, **self.mapper_args),
> File "<string>", line 2, in __init__
> File
> "/usr/local/lib/python3.8/dist-packages/sqlalchemy/util/deprecations.py",
> line 298, in warned
> return fn(*args, **kwargs)
> File "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/mapper.py",
> line 682, in __init__
> self._configure_class_instrumentation()
> File "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/mapper.py",
> line 1228, in _configure_class_instrumentation
> manager = instrumentation.register_class(
> File
> "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/instrumentation.py",
> line 574, in register_class
> manager._update_state(
> File
> "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/instrumentation.py",
> line 154, in _update_state
> self._finalize()
> File
> "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/instrumentation.py",
> line 163, in _finalize
> _instrumentation_factory.dispatch.class_instrument(self.class_)
> File "/usr/local/lib/python3.8/dist-packages/sqlalchemy/event/attr.py",
> line 343, in __call__
> fn(*args, **kw)
> File "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/events.py",
> line 79, in listen
> return fn(target_cls, *arg)
> File "/codebase_mountpoint/codebase/database/__init__.py", line 177, in
> set_serialize_map
> for c in visible_table_columns:
> File "/codebase_mountpoint/codebase/database/__init__.py", line 175, in
> <lambda>
> lambda x: cls.get_property_name_from_column(x) not in negatives,
> File "/codebase_mountpoint/codebase/database/__init__.py", line 106, in
> get_property_name_from_column
> return sqlalchemy.inspect(cls).get_property_by_column(column_obj).key
> File "/usr/local/lib/python3.8/dist-packages/sqlalchemy/orm/mapper.py",
> line 1998, in get_property_by_column
> return self._columntoproperty[column]
> AttributeError: 'Mapper' object has no attribute '_columntoproperty'
>
> On Friday, October 8, 2021 at 2:12:14 PM UTC-7 Mike Bayer wrote:
>>
>>
>> On Fri, Oct 8, 2021, at 4:13 PM, niuji...@gmail.com wrote:
>>> Thanks for this very important information!
>>>
>>> If I do want to utilize the mapper functions at this stage, what can I do?
>>> currently I have this error showing up:
>>>
>>> AttributeError: 'Mapper' object has no attribute '_columntoproperty'
>>
>> you would need to show me a stack trace on that. however, depending on
>> which event you are using to get at the mapper, it may not be initialized
>> yet (can confirm that class_instrument() event is too early if access to the
>> internals of the mapper is required). as stated previously, the best
>> event to use when a class is first mapped but before the full span of
>> mappings have been considered is the before_mapper_configured() event (can
>> confirm _columntoproperty is available at that stage).
>>
>>
>>
>>>
>>> On Friday, October 8, 2021 at 6:58:02 AM UTC-7 Mike Bayer wrote:
>>>>
>>>>
>>>> On Fri, Oct 8, 2021, at 7:09 AM, niuji...@gmail.com wrote:
>>>>> In order to make sure that the mapped class is fully ready, I chose the
>>>>> latest point, namely `class_instrument`.
>>>>> However, it seems that at that moment the `__mapper__` attribute is not
>>>>> available.
>>>>> When I tried
>>>>> return cls.__mapper__.get_property_by_column(column_obj).key
>>>>>
>>>>> I got:
>>>>> AttributeError: type object 'GeoAreaVariantName' has no attribute
>>>>> '__mapper__'
>>>>>
>>>>> Is this a bug or a feature?
>>>>
>>>> it's a normal behavior, that event is called before mapping has been
>>>> established.
>>>>
>>>> but also, the "__mapper__" attribute is a convenience feature that should
>>>> not be relied upon at this stage. the correct way to get the mapper for a
>>>> class is to use the sqlalchemy.inspect() function, i.e. mapper =
>>>> inspect(class).
>>>>
>>>>
>>>>
>>>>
>>>>>
>>>>> On Wednesday, October 6, 2021 at 5:36:22 AM UTC-7 Mike Bayer wrote:
>>>>>> __
>>>>>> events that occur around this time include
>>>>>>
>>>>>> this one claims it's before:
>>>>>>
>>>>>> https://docs.sqlalchemy.org/en/14/orm/events.html#sqlalchemy.orm.MapperEvents.instrument_class
>>>>>>
>>>>>> this one says after:
>>>>>>
>>>>>> https://docs.sqlalchemy.org/en/14/orm/events.html#sqlalchemy.orm.InstrumentationEvents.class_instrument
>>>>>>
>>>>>> this one is definitely after and is usually fine for anything that needs
>>>>>> to happen for mapped classes before they are reconciled against other
>>>>>> classes:
>>>>>>
>>>>>> https://docs.sqlalchemy.org/en/14/orm/events.html#sqlalchemy.orm.MapperEvents.before_mapper_configured
>>>>>>
>>>>>>
>>>>>> On Wed, Oct 6, 2021, at 4:48 AM, niuji...@gmail.com wrote:
>>>>>>> I want to do some after processing on each class that is just put into
>>>>>>> the class_registry. Is there a event hook for this?
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> SQLAlchemy -
>>>>>>> The Python SQL Toolkit and Object Relational Mapper
>>>>>>>
>>>>>>> http://www.sqlalchemy.org/
>>>>>>>
>>>>>>> To post example code, please provide an MCVE: Minimal, Complete, and
>>>>>>> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
>>>>>>> description.
>>>>>>> ---
>>>>>>> You received this message because you are subscribed to the Google
>>>>>>> Groups "sqlalchemy" group.
>>>>>>> To unsubscribe from this group and stop receiving emails from it, send
>>>>>>> an email to sqlalchemy+...@googlegroups.com.
>>>>>>> To view this discussion on the web visit
>>>>>>> https://groups.google.com/d/msgid/sqlalchemy/6ec43831-d59e-4343-99cf-dce3773a1216n%40googlegroups.com
>>>>>>>
>>>>>>> <https://groups.google.com/d/msgid/sqlalchemy/6ec43831-d59e-4343-99cf-dce3773a1216n%40googlegroups.com?utm_medium=email&utm_source=footer>.
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> SQLAlchemy -
>>>>> The Python SQL Toolkit and Object Relational Mapper
>>>>>
>>>>> http://www.sqlalchemy.org/
>>>>>
>>>>> To post example code, please provide an MCVE: Minimal, Complete, and
>>>>> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
>>>>> description.
>>>>> ---
>>>>> You received this message because you are subscribed to the Google Groups
>>>>> "sqlalchemy" group.
>>>>> To unsubscribe from this group and stop receiving emails from it, send an
>>>>> email to sqlalchemy+...@googlegroups.com.
>>>>> To view this discussion on the web visit
>>>>> https://groups.google.com/d/msgid/sqlalchemy/066675cb-164a-4f61-9764-15ac402b6a3bn%40googlegroups.com
>>>>>
>>>>> <https://groups.google.com/d/msgid/sqlalchemy/066675cb-164a-4f61-9764-15ac402b6a3bn%40googlegroups.com?utm_medium=email&utm_source=footer>.
>>>>
>>>
>>>
>>> --
>>> SQLAlchemy -
>>> The Python SQL Toolkit and Object Relational Mapper
>>>
>>> http://www.sqlalchemy.org/
>>>
>>> To post example code, please provide an MCVE: Minimal, Complete, and
>>> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
>>> description.
>>> ---
>>> You received this message because you are subscribed to the Google Groups
>>> "sqlalchemy" group.
>>> To unsubscribe from this group and stop receiving emails from it, send an
>>> email to sqlalchemy+...@googlegroups.com.
>>> To view this discussion on the web visit
>>> https://groups.google.com/d/msgid/sqlalchemy/fb457c38-74a2-4ce6-bb1c-35157347fd9fn%40googlegroups.com
>>>
>>> <https://groups.google.com/d/msgid/sqlalchemy/fb457c38-74a2-4ce6-bb1c-35157347fd9fn%40googlegroups.com?utm_medium=email&utm_source=footer>.
>>
>
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
>
> To post example code, please provide an MCVE: Minimal, Complete, and
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
> description.
> ---
> You received this message because you are subscribed to the Google Groups
> "sqlalchemy" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to sqlalchemy+unsubscr...@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/sqlalchemy/250c0fe7-2389-41e5-b86c-32065b9c9cean%40googlegroups.com
>
> <https://groups.google.com/d/msgid/sqlalchemy/250c0fe7-2389-41e5-b86c-32065b9c9cean%40googlegroups.com?utm_medium=email&utm_source=footer>.
--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
---
You received this message because you are subscribed to the Google Groups
"sqlalchemy" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sqlalchemy+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/sqlalchemy/63a58eec-0334-448c-81c5-c6cd95db6bb3%40www.fastmail.com.
