MotorClient
– Connection to MongoDB¶
- class motor.motor_tornado.MotorClient(*args, **kwargs)¶
Create a new connection to a single MongoDB instance at host:port.
Takes the same constructor arguments as
MongoClient
, as well as:- Parameters
io_loop (optional): Special event loop instance to use instead of default.
- client[db_name] || client.db_name
Get the db_name
MotorDatabase
onMotorClient
client.Raises
InvalidName
if an invalid database name is used.
- coroutine drop_database(name_or_database: Union[str, pymongo.database.Database], session: Optional[pymongo.client_session.ClientSession] = None, comment: Optional[Any] = None) None ¶
Drop a database.
Raises
TypeError
if name_or_database is not an instance ofbasestring
(str
in python 3) orDatabase
.- Parameters
name_or_database: the name of a database to drop, or a
Database
instance representing the database to dropsession (optional): a
ClientSession
.comment (optional): A user-provided comment to attach to this command.
Note
The
write_concern
of this client is automatically applied to this operation.
- get_database(name: Optional[str] = None, codec_options: Optional[bson.codec_options.CodecOptions] = None, read_preference: Optional[pymongo.read_preferences._ServerMode] = None, write_concern: Optional[pymongo.write_concern.WriteConcern] = None, read_concern: Optional[ReadConcern] = None) pymongo.database.Database[pymongo.typings._DocumentType] ¶
Get a
MotorDatabase
with the given name and options.Useful for creating a
MotorDatabase
with different codec options, read preference, and/or write concern from thisMotorClient
.>>> from pymongo import ReadPreference >>> client.read_preference == ReadPreference.PRIMARY True >>> db1 = client.test >>> db1.read_preference == ReadPreference.PRIMARY True >>> db2 = client.get_database( ... 'test', read_preference=ReadPreference.SECONDARY) >>> db2.read_preference == ReadPreference.SECONDARY True
- Parameters
name: The name of the database - a string.
codec_options (optional): An instance of
CodecOptions
. IfNone
(the default) thecodec_options
of thisMotorClient
is used.read_preference (optional): The read preference to use. If
None
(the default) theread_preference
of thisMotorClient
is used. Seeread_preferences
for options.write_concern (optional): An instance of
WriteConcern
. IfNone
(the default) thewrite_concern
of thisMotorClient
is used.
- get_default_database(default: Optional[str] = None, codec_options: Optional[bson.codec_options.CodecOptions] = None, read_preference: Optional[pymongo.read_preferences._ServerMode] = None, write_concern: Optional[pymongo.write_concern.WriteConcern] = None, read_concern: Optional[ReadConcern] = None) pymongo.database.Database[pymongo.typings._DocumentType] ¶
Get the database named in the MongoDB connection URI.
>>> uri = 'mongodb://host/my_database' >>> client = MotorClient(uri) >>> db = client.get_default_database() >>> assert db.name == 'my_database' >>> db = client.get_default_database('fallback_db_name') >>> assert db.name == 'my_database' >>> uri_without_database = 'mongodb://host/' >>> client = MotorClient(uri_without_database) >>> db = client.get_default_database('fallback_db_name') >>> assert db.name == 'fallback_db_name'
Useful in scripts where you want to choose which database to use based only on the URI in a configuration file.
- Parameters
default (optional): the database name to use if no database name was provided in the URI.
codec_options (optional): An instance of
CodecOptions
. IfNone
(the default) thecodec_options
of thisMotorClient
is used.read_preference (optional): The read preference to use. If
None
(the default) theread_preference
of thisMotorClient
is used. Seeread_preferences
for options.write_concern (optional): An instance of
WriteConcern
. IfNone
(the default) thewrite_concern
of thisMotorClient
is used.read_concern (optional): An instance of
ReadConcern
. IfNone
(the default) theread_concern
of thisMotorClient
is used.comment (optional): A user-provided comment to attach to this command.
Changed in version 3.0: Added
comment
parameter.New in version 2.1: Revived this method. Added the
default
,codec_options
,read_preference
,write_concern
andread_concern
parameters.Changed in version 2.0: Removed this method.
- coroutine list_database_names(session: Optional[pymongo.client_session.ClientSession] = None, comment: Optional[Any] = None) List[str] ¶
Get a list of the names of all databases on the connected server.
- Parameters
session (optional): a
ClientSession
.comment (optional): A user-provided comment to attach to this command.
- coroutine async list_databases(session: Optional[pymongo.client_session.ClientSession] = None, comment: Optional[Any] = None, **kwargs: Any) pymongo.command_cursor.CommandCursor[Dict[str, Any]] ¶
Get a cursor over the databases of the connected server.
- Parameters
session (optional): a
ClientSession
.comment (optional): A user-provided comment to attach to this command.
**kwargs (optional): Optional parameters of the listDatabases command can be passed as keyword arguments to this method. The supported options differ by server version.
- Returns
An instance of
CommandCursor
.
- coroutine server_info(session: Optional[pymongo.client_session.ClientSession] = None) Dict[str, Any] ¶
Get information about the MongoDB server we’re connected to.
- Parameters
session (optional): a
ClientSession
.
- coroutine async start_session(causal_consistency: Optional[bool] = None, default_transaction_options: Optional[pymongo.client_session.TransactionOptions] = None, snapshot: Optional[bool] = False) pymongo.client_session.ClientSession ¶
Start a logical session.
This method takes the same parameters as PyMongo’s
SessionOptions
. See theclient_session
module for details.This session is created uninitialized, use it in an
await
expression to initialize it, or anasync with
statement.async def coro(): collection = client.db.collection # End the session after using it. s = await client.start_session() await s.end_session() # Or, use an "async with" statement to end the session # automatically. async with await client.start_session() as s: doc = {'_id': ObjectId(), 'x': 1} await collection.insert_one(doc, session=s) secondary = collection.with_options( read_preference=ReadPreference.SECONDARY) # Sessions are causally consistent by default, so we can read # the doc we just inserted, even reading from a secondary. async for doc in secondary.find(session=s): print(doc) # Run a multi-document transaction: async with await client.start_session() as s: # Note, start_transaction doesn't require "await". async with s.start_transaction(): await collection.delete_one({'x': 1}, session=s) await collection.insert_one({'x': 2}, session=s) # Exiting the "with s.start_transaction()" block while throwing an # exception automatically aborts the transaction, exiting the block # normally automatically commits it. # You can run additional transactions in the same session, so long as # you run them one at a time. async with s.start_transaction(): await collection.insert_one({'x': 3}, session=s) await collection.insert_many({'x': {'$gte': 2}}, {'$inc': {'x': 1}}, session=s)
Requires MongoDB 3.6. Do not use the same session for multiple operations concurrently. A
MotorClientSession
may only be used with the MotorClient that started it.- Returns
An instance of
MotorClientSession
.
Changed in version 2.0: Returns a
MotorClientSession
. Before, this method returned a PyMongoClientSession
.New in version 1.2.
- watch(pipeline=None, full_document=None, resume_after=None, max_await_time_ms=None, batch_size=None, collation=None, start_at_operation_time=None, session=None, start_after=None, comment=None, full_document_before_change=None)¶
Watch changes on this cluster.
Returns a
MotorChangeStream
cursor which iterates over changes on all databases in this cluster. Introduced in MongoDB 4.0.See the documentation for
MotorCollection.watch()
for more details and examples.- Parameters
pipeline (optional): A list of aggregation pipeline stages to append to an initial
$changeStream
stage. Not all pipeline stages are valid after a$changeStream
stage, see the MongoDB documentation on change streams for the supported stages.full_document (optional): The fullDocument option to pass to the
$changeStream
stage. Allowed values: ‘updateLookup’. When set to ‘updateLookup’, the change notification for partial updates will include both a delta describing the changes to the document, as well as a copy of the entire document that was changed from some time after the change occurred.resume_after (optional): A resume token. If provided, the change stream will start returning changes that occur directly after the operation specified in the resume token. A resume token is the _id value of a change document.
max_await_time_ms (optional): The maximum time in milliseconds for the server to wait for changes before responding to a getMore operation.
batch_size (optional): The maximum number of documents to return per batch.
collation (optional): The
Collation
to use for the aggregation.start_at_operation_time (optional): If provided, the resulting change stream will only return changes that occurred at or after the specified
Timestamp
. Requires MongoDB >= 4.0.session (optional): a
ClientSession
.start_after (optional): The same as resume_after except that start_after can resume notifications after an invalidate event. This option and resume_after are mutually exclusive.
comment (optional): A user-provided comment to attach to this command.
- full_document_before_change: Allowed values: whenAvailable and required. Change events
may now result in a fullDocumentBeforeChange response field.
- Returns
Changed in version 3.1: Added
full_document_before_change
parameter.Changed in version 3.0: Added
comment
parameter.Changed in version 2.1: Added the
start_after
parameter.New in version 2.0.
- property HOST¶
str(object=’’) -> str str(bytes_or_buffer[, encoding[, errors]]) -> str
Create a new string object from the given object. If encoding or errors is specified, then the object must expose a data buffer that will be decoded using the given encoding and error handler. Otherwise, returns the result of object.__str__() (if defined) or repr(object). encoding defaults to sys.getdefaultencoding(). errors defaults to ‘strict’.
- property PORT¶
int([x]) -> integer int(x, base=10) -> integer
Convert a number or string to an integer, or return 0 if no arguments are given. If x is a number, return x.__int__(). For floating point numbers, this truncates towards zero.
If x is not a number or if base is given, then x must be a string, bytes, or bytearray instance representing an integer literal in the given base. The literal can be preceded by ‘+’ or ‘-‘ and be surrounded by whitespace. The base defaults to 10. Valid bases are 0 and 2-36. Base 0 means to interpret the base from the string as an integer literal. >>> int(‘0b100’, base=0) 4
- property address¶
(host, port) of the current standalone, primary, or mongos, or None.
Accessing
address
raisesInvalidOperation
if the client is load-balancing among mongoses, since there is no single address. Usenodes
instead.If the client is not connected, this will block until a connection is established or raise ServerSelectionTimeoutError if no server is available.
New in version 3.0.
- property arbiters¶
Arbiters in the replica set.
A sequence of (host, port) pairs. Empty if this client is not connected to a replica set, there are no arbiters, or this client was created without the replicaSet option.
- property close¶
Cleanup client resources and disconnect from MongoDB.
End all server sessions created by this client by sending one or more endSessions commands.
Close all sockets in the connection pools and stop the monitor threads.
Changed in version 4.0: Once closed, the client cannot be used again and any attempt will raise
InvalidOperation
.Changed in version 3.6: End all server sessions created by this client.
- property codec_options¶
Read only access to the
CodecOptions
of this instance.
- property is_mongos¶
If this client is connected to mongos. If the client is not connected, this will block until a connection is established or raise ServerSelectionTimeoutError if no server is available.
- property is_primary¶
If this client is connected to a server that can accept writes.
True if the current server is a standalone, mongos, or the primary of a replica set. If the client is not connected, this will block until a connection is established or raise ServerSelectionTimeoutError if no server is available.
- property nodes¶
Set of all currently connected servers.
Warning
When connected to a replica set the value of
nodes
can change over time asMongoClient
’s view of the replica set changes.nodes
can also be an empty set whenMongoClient
is first instantiated and hasn’t yet connected to any servers, or a network partition causes it to lose connection to all servers.
- property options¶
The configuration options for this client.
- Returns
An instance of
ClientOptions
.
New in version 4.0.
- property primary¶
The (host, port) of the current primary of the replica set.
Returns
None
if this client is not connected to a replica set, there is no primary, or this client was created without the replicaSet option.New in version 3.0: MongoClient gained this property in version 3.0.
- property read_concern¶
Read only access to the
ReadConcern
of this instance.New in version 3.2.
- property read_preference¶
Read only access to the read preference of this instance.
Changed in version 3.0: The
read_preference
attribute is now read only.
- property secondaries¶
The secondary members known to this client.
A sequence of (host, port) pairs. Empty if this client is not connected to a replica set, there are no visible secondaries, or this client was created without the replicaSet option.
New in version 3.0: MongoClient gained this property in version 3.0.
- property topology_description¶
The description of the connected MongoDB deployment.
>>> client.topology_description <TopologyDescription id: 605a7b04e76489833a7c6113, topology_type: ReplicaSetWithPrimary, servers: [<ServerDescription ('localhost', 27017) server_type: RSPrimary, rtt: 0.0007973677999995488>, <ServerDescription ('localhost', 27018) server_type: RSSecondary, rtt: 0.0005540556000003249>, <ServerDescription ('localhost', 27019) server_type: RSSecondary, rtt: 0.0010367483999999649>]> >>> client.topology_description.topology_type_name 'ReplicaSetWithPrimary'
Note that the description is periodically updated in the background but the returned object itself is immutable. Access this property again to get a more recent
TopologyDescription
.- Returns
An instance of
TopologyDescription
.
New in version 4.0.
- property write_concern¶
Read only access to the
WriteConcern
of this instance.Changed in version 3.0: The
write_concern
attribute is now read only.