PYTHON-3247 Mitigate user issues caused by change in directConnection defaults in 4.x #935
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pymongo/mongo_client.py
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| """Client for a MongoDB instance, a replica set, or a set of mongoses. | ||
| .. warning:: Starting in PyMongo 4.0, ``directConnection`` now has a default value of | ||
| False instead of None (which is the same as specifying ``directionConnection=True``). |
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"(which is the same as specifying directionConnection=True)" is not quite correct. Let's remove that part.
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Bernie mentioned that fact explicitly in the ticket, so I thought it would be good to include so that user understands that None does not equal False (as I would assume). What about making it more clear by saying that is "functionally" the same? Or is that still not the case.
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directConnection=None is not supported in PyMongo 4:
>>> c = MongoClient(directConnection=None)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/Users/shane/git/mongo-python-driver/pymongo/mongo_client.py", line 747, in __init__
dict(common.validate(keyword_opts.cased_key(k), v) for k, v in keyword_opts.items())
File "/Users/shane/git/mongo-python-driver/pymongo/mongo_client.py", line 747, in <genexpr>
dict(common.validate(keyword_opts.cased_key(k), v) for k, v in keyword_opts.items())
File "/Users/shane/git/mongo-python-driver/pymongo/common.py", line 754, in validate
value = validator(option, value)
File "/Users/shane/git/mongo-python-driver/pymongo/common.py", line 185, in validate_boolean_or_string
return validate_boolean(option, value)
File "/Users/shane/git/mongo-python-driver/pymongo/common.py", line 176, in validate_boolean
raise TypeError("%s must be True or False" % (option,))
TypeError: directConnection must be True or False
In PyMongo 3 directConnection=None means: use the legacy pymongo 3 discovery behavior (ie 1 host -> direct, >1 host -> auto discover).
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Oh, ok that makes sense. Will leave it removed then.
doc/changelog.rst
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| discovery of replica sets. This means that if you | ||
| want a direct connection to a single server you must pass | ||
| ``directConnection=True`` as a URI option or keyword argument. | ||
| See the :doc:`migrate-to-pymongo4` for more details. |
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Can we link to the directConnection section in the migration guide?
doc/migrate-to-pymongo4.rst
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| doc = client.admin.command('hello') | ||
| result = doc['isWritablePrimary'] | ||
| print(result) | ||
| >> True |
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The >> True seems a little odd. How about?:
>>> client.admin.command('hello')['isWritablePrimary']
True
doc/migrate-to-pymongo4.rst
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| want a direct connection to a single server you must pass | ||
| ``directConnection=True`` as a URI option or keyword argument. | ||
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| Here are some example errors that you might see |
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What do you think about adding something like "If you see any ServerSelectionTimeoutError after upgrading from 3 to 4, you likely need to add directConnection=True when creating the client. Here are some example errors:"
| defaults to ``False`` instead of ``None``, allowing for the automatic | ||
| discovery of replica sets. This means that if you | ||
| want a direct connection to a single server you must pass | ||
| ``directConnection=True`` as a URI option or keyword argument. |
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I think we should keep this in the list here too just for more visibility.
pymongo/mongo_client.py
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| Please see the :ref:`pymongo4-migration-guide` for more details. | ||
| False instead of None. | ||
| For more details, see the relevant section of the PyMongo 4.x migration guide: | ||
| :ref:`pymongo4-migration-direct-connection`. |
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These lines are under-indented now: https://readthedocs.org/projects/pymongo/builds/16807087/
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Oops, my bad. Copy and pasted it wrong. Fixed.
ShaneHarvey
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ShaneHarvey
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LGTM with one small change
doc/migrate-to-pymongo4.rst
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| .. code-block:: | ||
| _select_servers_loop | ||
| raise ServerSelectionTimeoutError( |
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Let's remove these two lines:
_select_servers_loop
raise ServerSelectionTimeoutError(
… defaults in 4.x (mongodb#935)
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