Re: [sqlalchemy] Temporarily disable/intercept ORM events on mutation

2023-09-15 Thread Mike Bayer 


On Fri, Sep 15, 2023, at 8:59 PM, Mike Bayer wrote:
> 
> unfortunately no, that's a backref event handler, that's within the class 
> instrumentation and has no mechanism to be disabled on a per-class basis, not 
> to mention the backref handler is not the only aspect of things that expects 
> a certain kind of value to be present.  Marshmallow should have alternate 
> APIs that allow the attributes in question to be named by their string name 
> somewhere, rather than being assigned some out-of-band object; that's not 
> very good design in today's pep-484 typed Python.

sorry, I meant "no mechanism to be disabled on a per-instance basis". 

> 
> 
> 
> 
> 
>> 
>> 
>> --
>> 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/34ee3121-e284-4fcb-9c1d-6191557e89bcn%40googlegroups.com
>>  
>> .
> 

-- 
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/0183d49d-e442-4512-bf62-8adae2c0e903%40app.fastmail.com.

Re: [sqlalchemy] Temporarily disable/intercept ORM events on mutation

2023-09-15 Thread Mike Bayer 


On Fri, Sep 15, 2023, at 4:28 PM, 'Luna Lucadou' via sqlalchemy wrote:
> When customers call our JSON:API API, they can use an "include" parameter to 
> specify related objects to be appended to the response.
> 
> However, requests to include are not always satisfiable (e.g. if 
> job.supervisor=null, include=supervisor is ignored).
> In order to prevent Marshmallow from trying to load nonexistent related 
> objects to append to our API responses, we need to tell it when to ignore a 
> relationship attribute, such as via setting 
> job.supervisor=marshmallow.missing (if it sees job.supervisor=None, it will 
> attempt (and fail) to load the null supervisor object, so we cannot just 
> leave it as-is).
> 
> Unfortunately, this causes problems as SQLAlchemy attempts to handle the new 
> value:
> 
> Error Traceback (most recent call last): File 
> "/Users/lucadou/IdeaProjects/person-api/api/unit_tests/test_person_service.py",
>  line 601, in test_get_people_include_job response = 
> self.person_service.get_people(QueryParameters({"include": "jobs"})) 
>  File 
> "/Users/lucadou/IdeaProjects/person-api/api/src/person_service.py", line 61, 
> in get_people response = person_schema.dump(people, many=True) 
> ^ File 
> "/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow/schema.py",
>  line 557, in dump result = self._serialize(processed_obj, many=many) 
> ^ File 
> "/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow/schema.py",
>  line 519, in _serialize return [ ^ File 
> "/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow/schema.py",
>  line 520, in  self._serialize(d, many=False) File 
> "/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow/schema.py",
>  line 525, in _serialize value = field_obj.serialize(attr_name, obj, 
> accessor=self.get_attribute) 
>  File 
> "/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow_jsonapi/fields.py",
>  line 248, in serialize return super().serialize(attr, obj, accessor) 
> ^^ File 
> "/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow/fields.py",
>  line 344, in serialize return self._serialize(value, attr, obj, **kwargs) 
> ^^^ File 
> "/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow_jsonapi/fields.py",
>  line 274, in _serialize self._serialize_included(item) File 
> "/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow_jsonapi/fields.py",
>  line 280, in _serialize_included result = self.schema.dump(value) 
> ^^^ File 
> "/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow/schema.py",
>  line 551, in dump processed_obj = self._invoke_dump_processors( 
> ^ File 
> "/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow/schema.py",
>  line 1068, in _invoke_dump_processors data = self._invoke_processors( 
>  File 
> "/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow/schema.py",
>  line 1225, in _invoke_processors data = processor(data, many=many, **kwargs) 
>  File 
> "/Users/lucadou/IdeaProjects/person-api/api/src/model/schema/job_schema.py", 
> line 62, in set_null_supervisor job.supervisor = missing ^^ File 
> "/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/sqlalchemy/orm/attributes.py",
>  line 536, in __set__ self.impl.set( File 
> "/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/sqlalchemy/orm/attributes.py",
>  line 1466, in set value = self.fire_replace_event(state, dict_, value, old, 
> initiator)  File 
> "/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/sqlalchemy/orm/attributes.py",
>  line 1505, in fire_replace_event value = fn( ^^^ File 
> "/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/sqlalchemy/orm/attributes.py",
>  line 2167, in emit_backref_from_scalar_set_event instance_state(child), 
> ^ AttributeError: '_Missing' object has no attribute 
> '_sa_instance_state'
> 
> Is there any way to temporarily disable ORM event listeners when we mutate 
> objects and have no intention of saving the changes/do not intend for the ORM 
> to act on them?

unfortunately no, that's a backref event handler, that's within the class 
instrumentation and has no mechanism to be

[sqlalchemy] Temporarily disable/intercept ORM events on mutation

2023-09-15 Thread 'Luna Lucadou' via sqlalchemy 
When customers call our JSON:API API, they can use an "include" parameter 
to specify related objects to be appended to the response.

However, requests to include are not always satisfiable (e.g. if 
job.supervisor=null, include=supervisor is ignored).
In order to prevent Marshmallow from trying to load nonexistent related 
objects to append to our API responses, we need to tell it when to ignore a 
relationship attribute, such as via setting 
job.supervisor=marshmallow.missing (if it sees job.supervisor=None, it will 
attempt (and fail) to load the null supervisor object, so we cannot just 
leave it as-is).

Unfortunately, this causes problems as SQLAlchemy attempts to handle the 
new value:

Error Traceback (most recent call last): File 
"/Users/lucadou/IdeaProjects/person-api/api/unit_tests/test_person_service.py", 
line 601, in test_get_people_include_job response = 
self.person_service.get_people(QueryParameters({"include": "jobs"})) 
 File 
"/Users/lucadou/IdeaProjects/person-api/api/src/person_service.py", line 
61, in get_people response = person_schema.dump(people, many=True) 
^ File 
"/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow/schema.py",
 
line 557, in dump result = self._serialize(processed_obj, many=many) 
^ File 
"/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow/schema.py",
 
line 519, in _serialize return [ ^ File 
"/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow/schema.py",
 
line 520, in  self._serialize(d, many=False) File 
"/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow/schema.py",
 
line 525, in _serialize value = field_obj.serialize(attr_name, obj, 
accessor=self.get_attribute) 
 File 
"/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow_jsonapi/fields.py",
 
line 248, in serialize return super().serialize(attr, obj, accessor) 
^^ File 
"/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow/fields.py",
 
line 344, in serialize return self._serialize(value, attr, obj, **kwargs) 
^^^ File 
"/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow_jsonapi/fields.py",
 
line 274, in _serialize self._serialize_included(item) File 
"/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow_jsonapi/fields.py",
 
line 280, in _serialize_included result = self.schema.dump(value) 
^^^ File 
"/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow/schema.py",
 
line 551, in dump processed_obj = self._invoke_dump_processors( 
^ File 
"/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow/schema.py",
 
line 1068, in _invoke_dump_processors data = self._invoke_processors( 
 File 
"/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/marshmallow/schema.py",
 
line 1225, in _invoke_processors data = processor(data, many=many, **kwargs) 
 File 
"/Users/lucadou/IdeaProjects/person-api/api/src/model/schema/job_schema.py", 
line 62, in set_null_supervisor job.supervisor = missing ^^ File 
"/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/sqlalchemy/orm/attributes.py",
 
line 536, in __set__ self.impl.set( File 
"/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/sqlalchemy/orm/attributes.py",
 
line 1466, in set value = self.fire_replace_event(state, dict_, value, old, 
initiator)  File 
"/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/sqlalchemy/orm/attributes.py",
 
line 1505, in fire_replace_event value = fn( ^^^ File 
"/Users/lucadou/IdeaProjects/person-api/api/venv/lib/python3.11/site-packages/sqlalchemy/orm/attributes.py",
 
line 2167, in emit_backref_from_scalar_set_event instance_state(child), 
^ AttributeError: '_Missing' object has no attribute 
'_sa_instance_state'

Is there any way to temporarily disable ORM event listeners when we mutate 
objects and have no intention of saving the changes/do not intend for the 
ORM to act on them?

-- 
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