mongo_client – Tools for connecting to MongoDB
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`mongo_client` – Tools for connecting to MongoDB

Tools for connecting to MongoDB.

See also

High Availability and PyMongo for examples of connecting to replica sets or sets of mongos servers.

To get a Database instance from a MongoClient use either dictionary-style or attribute-style access:

>>> from pymongo import MongoClient
>>> c = MongoClient()
>>> c.test_database
Database(MongoClient(host=['localhost:27017'], document_class=dict, tz_aware=False, connect=True), u'test_database')
>>> c['test-database']
Database(MongoClient(host=['localhost:27017'], document_class=dict, tz_aware=False, connect=True), u'test-database')

class pymongo.mongo_client.``MongoClient(host=’localhost’, port=27017, document_class=dict, tz_aware=False, connect=True, \*kwargs*)

Client for a MongoDB instance, a replica set, or a set of mongoses.

The client object is thread-safe and has connection-pooling built in. If an operation fails because of a network error, ConnectionFailure is raised and the client reconnects in the background. Application code should handle this exception (recognizing that the operation failed) and then continue to execute.

The host parameter can be a full mongodb URI, in addition to a simple hostname. It can also be a list of hostnames or URIs. Any port specified in the host string(s) will override the port parameter. If multiple mongodb URIs containing database or auth information are passed, the last database, username, and password present will be used. For username and passwords reserved characters like ‘:’, ‘/’, ‘+’ and ‘@’ must be percent encoded following RFC 2396:

try:
    # Python 3.x
    from urllib.parse import quote_plus
except ImportError:
    # Python 2.x
    from urllib import quote_plus
uri = "mongodb://%s:%s@%s" % (
    quote_plus(user), quote_plus(password), host)
client = MongoClient(uri)

Unix domain sockets are also supported. The socket path must be percent encoded in the URI:

uri = "mongodb://%s:%s@%s" % (
    quote_plus(user), quote_plus(password), quote_plus(socket_path))
client = MongoClient(uri)

But not when passed as a simple hostname:

client = MongoClient('/tmp/mongodb-27017.sock')

Starting with version 3.6, PyMongo supports mongodb+srv:// URIs. The URI must include one, and only one, hostname. The hostname will be resolved to one or more DNS SRV records which will be used as the seed list for connecting to the MongoDB deployment. When using SRV URIs, the authSource and replicaSet configuration options can be specified using TXT records. See the Initial DNS Seedlist Discovery spec for more details. Note that the use of SRV URIs implicitly enables TLS support. Pass tls=false in the URI to override.

Note

MongoClient creation will block waiting for answers from DNS when mongodb+srv:// URIs are used.

Note

Starting with version 3.0 the MongoClient constructor no longer blocks while connecting to the server or servers, and it no longer raises ConnectionFailure if they are unavailable, nor ConfigurationError if the user’s credentials are wrong. Instead, the constructor returns immediately and launches the connection process on background threads. You can check if the server is available like this:

from pymongo.errors import ConnectionFailure
client = MongoClient()
try:
    # The ismaster command is cheap and does not require auth.
    client.admin.command('ismaster')
except ConnectionFailure:
    print("Server not available")

Warning

When using PyMongo in a multiprocessing context, please read Using PyMongo with Multiprocessing first.

Note

Many of the following options can be passed using a MongoDB URI or keyword parameters. If the same option is passed in a URI and as a keyword parameter the keyword parameter takes precedence.

Parameters:

Parameters:	host (optional): hostname or IP address or Unix domain socket path of a single mongod or mongos instance to connect to, or a mongodb URI, or a list of hostnames / mongodb URIs. If host is an IPv6 literal it must be enclosed in ‘[‘ and ‘]’ characters following the RFC2732 URL syntax (e.g. ‘[::1]’ for localhost). Multihomed and round robin DNS addresses are not supported. port (optional): port number on which to connect document_class (optional): default class to use for documents returned from queries on this client type_registry (optional): instance of `TypeRegistry` to enable encoding and decoding of custom types. tz_aware (optional): if `True`, `datetime` instances returned as values in a document by this `MongoClient` will be timezone aware (otherwise they will be naive) connect (optional): if `True` (the default), immediately begin connecting to MongoDB in the background. Otherwise connect on the first operation. directConnection (optional): if `True`, forces this client to connect directly to the specified MongoDB host as a standalone. If `false`, the client connects to the entire replica set of which the given MongoDB host(s) is a part. If this is `True` and a mongodb+srv:// URI or a URI containing multiple seeds is provided, an exception will be raised. Other optional parameters can be passed as keyword arguments: maxPoolSize (optional): The maximum allowable number of concurrent connections to each connected server. Requests to a server will block if there are maxPoolSize outstanding connections to the requested server. Defaults to 100. Cannot be 0. minPoolSize (optional): The minimum required number of concurrent connections that the pool will maintain to each connected server. Default is 0. maxIdleTimeMS (optional): The maximum number of milliseconds that a connection can remain idle in the pool before being removed and replaced. Defaults to None (no limit). socketTimeoutMS: (integer or None) Controls how long (in milliseconds) the driver will wait for a response after sending an ordinary (non-monitoring) database operation before concluding that a network error has occurred. `0` or `None` means no timeout. Defaults to `None` (no timeout). connectTimeoutMS: (integer or None) Controls how long (in milliseconds) the driver will wait during server monitoring when connecting a new socket to a server before concluding the server is unavailable. `0` or `None` means no timeout. Defaults to `20000` (20 seconds). server_selector: (callable or None) Optional, user-provided function that augments server selection rules. The function should accept as an argument a list of `ServerDescription` objects and return a list of server descriptions that should be considered suitable for the desired operation. serverSelectionTimeoutMS: (integer) Controls how long (in milliseconds) the driver will wait to find an available, appropriate server to carry out a database operation; while it is waiting, multiple server monitoring operations may be carried out, each controlled by connectTimeoutMS. Defaults to `30000` (30 seconds). waitQueueTimeoutMS: (integer or None) How long (in milliseconds) a thread will wait for a socket from the pool if the pool has no free sockets. Defaults to `None` (no timeout). waitQueueMultiple: (integer or None) Multiplied by maxPoolSize to give the number of threads allowed to wait for a socket at one time. Defaults to `None` (no limit). heartbeatFrequencyMS: (optional) The number of milliseconds between periodic server checks, or None to accept the default frequency of 10 seconds. appname: (string or None) The name of the application that created this MongoClient instance. MongoDB 3.4 and newer will print this value in the server log upon establishing each connection. It is also recorded in the slow query log and profile collections. driver: (pair or None) A driver implemented on top of PyMongo can pass a `DriverInfo` to add its name, version, and platform to the message printed in the server log when establishing a connection. event_listeners: a list or tuple of event listeners. See `monitoring` for details. retryWrites: (boolean) Whether supported write operations executed within this MongoClient will be retried once after a network error on MongoDB 3.6+. Defaults to `True`. The supported write operations are: `bulk_write()`, as long as `UpdateMany` or `DeleteMany` are not included. `delete_one()` `insert_one()` `insert_many()` `replace_one()` `update_one()` `find_one_and_delete()` `find_one_and_replace()` `find_one_and_update()` Unsupported write operations include, but are not limited to, `aggregate()` using the `$out` pipeline operator and any operation with an unacknowledged write concern (e.g. {w: 0})). See https://github.com/mongodb/specifications/blob/master/source/retryable-writes/retryable-writes.rst retryReads: (boolean) Whether supported read operations executed within this MongoClient will be retried once after a network error on MongoDB 3.6+. Defaults to `True`. The supported read operations are: `find()`, `find_one()`, `aggregate()` without `$out`, `distinct()`, `count()`, `estimated_document_count()`, `count_documents()`, `pymongo.collection.Collection.watch()`, `list_indexes()`, `pymongo.database.Database.watch()`, `list_collections()`, `pymongo.mongo_client.MongoClient.watch()`, and `list_databases()`. Unsupported read operations include, but are not limited to: `map_reduce()`, `inline_map_reduce()`, `command()`, and any getMore operation on a cursor. Enabling retryable reads makes applications more resilient to transient errors such as network failures, database upgrades, and replica set failovers. For an exact definition of which errors trigger a retry, see the retryable reads specification. socketKeepAlive: (boolean) DEPRECATED Whether to send periodic keep-alive packets on connected sockets. Defaults to `True`. Disabling it is not recommended, see https://docs.mongodb.com/manual/faq/diagnostics/#does-tcp-keepalive-time-affect-mongodb-deployments”, compressors: Comma separated list of compressors for wire protocol compression. The list is used to negotiate a compressor with the server. Currently supported options are “snappy”, “zlib” and “zstd”. Support for snappy requires the python-snappy package. zlib support requires the Python standard library zlib module. zstd requires the zstandard package. By default no compression is used. Compression support must also be enabled on the server. MongoDB 3.4+ supports snappy compression. MongoDB 3.6 adds support for zlib. MongoDB 4.2 adds support for zstd. zlibCompressionLevel: (int) The zlib compression level to use when zlib is used as the wire protocol compressor. Supported values are -1 through 9. -1 tells the zlib library to use its default compression level (usually 6). 0 means no compression. 1 is best speed. 9 is best compression. Defaults to -1. uuidRepresentation: The BSON representation to use when encoding from and decoding to instances of `UUID`. Valid values are pythonLegacy (the default), javaLegacy, csharpLegacy, standard and unspecified. New applications should consider setting this to standard for cross language compatibility. See Handling UUID Data for details. Write Concern options: (Only set if passed. No default values.) w: (integer or string) If this is a replica set, write operations will block until they have been replicated to the specified number or tagged set of servers. w=<int> always includes the replica set primary (e.g. w=3 means write to the primary and wait until replicated to two secondaries). Passing w=0 disables write acknowledgement and all other write concern options. wTimeoutMS: (integer) Used in conjunction with w. Specify a value in milliseconds to control how long to wait for write propagation to complete. If replication does not complete in the given timeframe, a timeout exception is raised. Passing wTimeoutMS=0 will cause write operations to wait indefinitely. journal: If `True` block until write operations have been committed to the journal. Cannot be used in combination with fsync. Prior to MongoDB 2.6 this option was ignored if the server was running without journaling. Starting with MongoDB 2.6 write operations will fail with an exception if this option is used when the server is running without journaling. fsync: If `True` and the server is running without journaling, blocks until the server has synced all data files to disk. If the server is running with journaling, this acts the same as the j option, blocking until write operations have been committed to the journal. Cannot be used in combination with j. Replica set keyword arguments for connecting with a replica set - either directly or via a mongos: replicaSet: (string or None) The name of the replica set to connect to. The driver will verify that all servers it connects to match this name. Implies that the hosts specified are a seed list and the driver should attempt to find all members of the set. Defaults to `None`. Read Preference: readPreference: The replica set read preference for this client. One of `primary`, `primaryPreferred`, `secondary`, `secondaryPreferred`, or `nearest`. Defaults to `primary`. readPreferenceTags: Specifies a tag set as a comma-separated list of colon-separated key-value pairs. For example `dc:ny,rack:1`. Defaults to `None`. maxStalenessSeconds: (integer) The maximum estimated length of time a replica set secondary can fall behind the primary in replication before it will no longer be selected for operations. Defaults to `-1`, meaning no maximum. If maxStalenessSeconds is set, it must be a positive integer greater than or equal to 90 seconds. See also Server Selector Example Authentication: username: A string. password: A string. Although username and password must be percent-escaped in a MongoDB URI, they must not be percent-escaped when passed as parameters. In this example, both the space and slash special characters are passed as-is: `MongoClient(username=”user name”, password=”pass/word”)` authSource: The database to authenticate on. Defaults to the database specified in the URI, if provided, or to “admin”. authMechanism: See `MECHANISMS` for options. If no mechanism is specified, PyMongo automatically uses MONGODB-CR when connected to a pre-3.0 version of MongoDB, SCRAM-SHA-1 when connected to MongoDB 3.0 through 3.6, and negotiates the mechanism to use (SCRAM-SHA-1 or SCRAM-SHA-256) when connected to MongoDB 4.0+. authMechanismProperties: Used to specify authentication mechanism specific options. To specify the service name for GSSAPI authentication pass authMechanismProperties=’SERVICE_NAME:<service name>’. To specify the session token for MONGODB-AWS authentication pass `authMechanismProperties=’AWS_SESSION_TOKEN:<session token>’`. See also Authentication Examples TLS/SSL configuration: tls: (boolean) If `True`, create the connection to the server using transport layer security. Defaults to `False`. tlsInsecure: (boolean) Specify whether TLS constraints should be relaxed as much as possible. Setting `tlsInsecure=True` implies `tlsAllowInvalidCertificates=True` and `tlsAllowInvalidHostnames=True`. Defaults to `False`. Think very carefully before setting this to `True` as it dramatically reduces the security of TLS. tlsAllowInvalidCertificates: (boolean) If `True`, continues the TLS handshake regardless of the outcome of the certificate verification process. If this is `False`, and a value is not provided for `tlsCAFile`, PyMongo will attempt to load system provided CA certificates. If the python version in use does not support loading system CA certificates then the `tlsCAFile` parameter must point to a file of CA certificates. `tlsAllowInvalidCertificates=False` implies `tls=True`. Defaults to `False`. Think very carefully before setting this to `True` as that could make your application vulnerable to man-in-the-middle attacks. tlsAllowInvalidHostnames: (boolean) If `True`, disables TLS hostname verification. `tlsAllowInvalidHostnames=False` implies `tls=True`. Defaults to `False`. Think very carefully before setting this to `True` as that could make your application vulnerable to man-in-the-middle attacks. tlsCAFile: A file containing a single or a bundle of “certification authority” certificates, which are used to validate certificates passed from the other end of the connection. Implies `tls=True`. Defaults to `None`. tlsCertificateKeyFile: A file containing the client certificate and private key. If you want to pass the certificate and private key as separate files, use the `ssl_certfile` and `ssl_keyfile` options instead. Implies `tls=True`. Defaults to `None`. tlsCRLFile: A file containing a PEM or DER formatted certificate revocation list. Only supported by python 2.7.9+ (pypy 2.5.1+). Implies `tls=True`. Defaults to `None`. tlsCertificateKeyFilePassword: The password or passphrase for decrypting the private key in `tlsCertificateKeyFile` or `ssl_keyfile`. Only necessary if the private key is encrypted. Only supported by python 2.7.9+ (pypy 2.5.1+) and 3.3+. Defaults to `None`. tlsDisableOCSPEndpointCheck: (boolean) If `True`, disables certificate revocation status checking via the OCSP responder specified on the server certificate. Defaults to `False`. ssl: (boolean) Alias for `tls`. ssl_certfile: The certificate file used to identify the local connection against mongod. Implies `tls=True`. Defaults to `None`. ssl_keyfile: The private keyfile used to identify the local connection against mongod. Can be omitted if the keyfile is included with the `tlsCertificateKeyFile`. Implies `tls=True`. Defaults to `None`. Read Concern options: (If not set explicitly, this will use the server default) readConcernLevel: (string) The read concern level specifies the level of isolation for read operations. For example, a read operation using a read concern level of `majority` will only return data that has been written to a majority of nodes. If the level is left unspecified, the server default will be used. Client side encryption options: (If not set explicitly, client side encryption will not be enabled.) auto_encryption_opts: A `AutoEncryptionOpts` which configures this client to automatically encrypt collection commands and automatically decrypt results. See Automatic Client-Side Field Level Encryption for an example.

host (optional): hostname or IP address or Unix domain socket path of a single mongod or mongos instance to connect to, or a mongodb URI, or a list of hostnames / mongodb URIs. If host is an IPv6 literal it must be enclosed in ‘[‘ and ‘]’ characters following the RFC2732 URL syntax (e.g. ‘[::1]’ for localhost). Multihomed and round robin DNS addresses are not supported.
port (optional): port number on which to connect
document_class (optional): default class to use for documents returned from queries on this client
type_registry (optional): instance of TypeRegistry to enable encoding and decoding of custom types.
tz_aware (optional): if True, datetime instances returned as values in a document by this MongoClient will be timezone aware (otherwise they will be naive)
connect (optional): if True (the default), immediately begin connecting to MongoDB in the background. Otherwise connect on the first operation.
directConnection (optional): if True, forces this client to
connect directly to the specified MongoDB host as a standalone. If false, the client connects to the entire replica set of which the given MongoDB host(s) is a part. If this is True and a mongodb+srv:// URI or a URI containing multiple seeds is provided, an exception will be raised.

Other optional parameters can be passed as keyword arguments:

maxPoolSize (optional): The maximum allowable number of concurrent connections to each connected server. Requests to a server will block if there are maxPoolSize outstanding connections to the requested server. Defaults to 100. Cannot be 0.
minPoolSize (optional): The minimum required number of concurrent connections that the pool will maintain to each connected server. Default is 0.
maxIdleTimeMS (optional): The maximum number of milliseconds that a connection can remain idle in the pool before being removed and replaced. Defaults to None (no limit).
socketTimeoutMS: (integer or None) Controls how long (in milliseconds) the driver will wait for a response after sending an ordinary (non-monitoring) database operation before concluding that a network error has occurred. 0 or None means no timeout. Defaults to None (no timeout).
connectTimeoutMS: (integer or None) Controls how long (in milliseconds) the driver will wait during server monitoring when connecting a new socket to a server before concluding the server is unavailable. 0 or None means no timeout. Defaults to 20000 (20 seconds).
server_selector: (callable or None) Optional, user-provided function that augments server selection rules. The function should accept as an argument a list of ServerDescription objects and return a list of server descriptions that should be considered suitable for the desired operation.
serverSelectionTimeoutMS: (integer) Controls how long (in milliseconds) the driver will wait to find an available, appropriate server to carry out a database operation; while it is waiting, multiple server monitoring operations may be carried out, each controlled by connectTimeoutMS. Defaults to 30000 (30 seconds).
waitQueueTimeoutMS: (integer or None) How long (in milliseconds) a thread will wait for a socket from the pool if the pool has no free sockets. Defaults to None (no timeout).
waitQueueMultiple: (integer or None) Multiplied by maxPoolSize to give the number of threads allowed to wait for a socket at one time. Defaults to None (no limit).
heartbeatFrequencyMS: (optional) The number of milliseconds between periodic server checks, or None to accept the default frequency of 10 seconds.
appname: (string or None) The name of the application that created this MongoClient instance. MongoDB 3.4 and newer will print this value in the server log upon establishing each connection. It is also recorded in the slow query log and profile collections.
driver: (pair or None) A driver implemented on top of PyMongo can pass a DriverInfo to add its name, version, and platform to the message printed in the server log when establishing a connection.
event_listeners: a list or tuple of event listeners. See monitoring for details.
retryWrites: (boolean) Whether supported write operations executed within this MongoClient will be retried once after a network error on MongoDB 3.6+. Defaults to True. The supported write operations are:
- bulk_write(), as long as UpdateMany or DeleteMany are not included.
- delete_one()
- insert_one()
- insert_many()
- replace_one()
- update_one()
- find_one_and_delete()
- find_one_and_replace()
- find_one_and_update()
Unsupported write operations include, but are not limited to, aggregate() using the $out pipeline operator and any operation with an unacknowledged write concern (e.g. {w: 0})). See https://github.com/mongodb/specifications/blob/master/source/retryable-writes/retryable-writes.rst
retryReads: (boolean) Whether supported read operations executed within this MongoClient will be retried once after a network error on MongoDB 3.6+. Defaults to True. The supported read operations are: find(), find_one(), aggregate() without $out, distinct(), count(), estimated_document_count(), count_documents(), pymongo.collection.Collection.watch(), list_indexes(), pymongo.database.Database.watch(), list_collections(), pymongo.mongo_client.MongoClient.watch(), and list_databases().
Unsupported read operations include, but are not limited to: map_reduce(), inline_map_reduce(), command(), and any getMore operation on a cursor.
Enabling retryable reads makes applications more resilient to transient errors such as network failures, database upgrades, and replica set failovers. For an exact definition of which errors trigger a retry, see the retryable reads specification.
socketKeepAlive: (boolean) DEPRECATED Whether to send periodic keep-alive packets on connected sockets. Defaults to True. Disabling it is not recommended, see https://docs.mongodb.com/manual/faq/diagnostics/#does-tcp-keepalive-time-affect-mongodb-deployments”,
compressors: Comma separated list of compressors for wire protocol compression. The list is used to negotiate a compressor with the server. Currently supported options are “snappy”, “zlib” and “zstd”. Support for snappy requires the python-snappy package. zlib support requires the Python standard library zlib module. zstd requires the zstandard package. By default no compression is used. Compression support must also be enabled on the server. MongoDB 3.4+ supports snappy compression. MongoDB 3.6 adds support for zlib. MongoDB 4.2 adds support for zstd.
zlibCompressionLevel: (int) The zlib compression level to use when zlib is used as the wire protocol compressor. Supported values are -1 through 9. -1 tells the zlib library to use its default compression level (usually 6). 0 means no compression. 1 is best speed. 9 is best compression. Defaults to -1.
uuidRepresentation: The BSON representation to use when encoding from and decoding to instances of UUID. Valid values are pythonLegacy (the default), javaLegacy, csharpLegacy, standard and unspecified. New applications should consider setting this to standard for cross language compatibility. See Handling UUID Data for details.

Write Concern options:

(Only set if passed. No default values.)

w: (integer or string) If this is a replica set, write operations will block until they have been replicated to the specified number or tagged set of servers. w=<int> always includes the replica set primary (e.g. w=3 means write to the primary and wait until replicated to two secondaries). Passing w=0 disables write acknowledgement and all other write concern options.
wTimeoutMS: (integer) Used in conjunction with w. Specify a value in milliseconds to control how long to wait for write propagation to complete. If replication does not complete in the given timeframe, a timeout exception is raised. Passing wTimeoutMS=0 will cause write operations to wait indefinitely.
journal: If True block until write operations have been committed to the journal. Cannot be used in combination with fsync. Prior to MongoDB 2.6 this option was ignored if the server was running without journaling. Starting with MongoDB 2.6 write operations will fail with an exception if this option is used when the server is running without journaling.
fsync: If True and the server is running without journaling, blocks until the server has synced all data files to disk. If the server is running with journaling, this acts the same as the j option, blocking until write operations have been committed to the journal. Cannot be used in combination with j.

Replica set keyword arguments for connecting with a replica set - either directly or via a mongos:

replicaSet: (string or None) The name of the replica set to connect to. The driver will verify that all servers it connects to match this name. Implies that the hosts specified are a seed list and the driver should attempt to find all members of the set. Defaults to None.

Read Preference:

readPreference: The replica set read preference for this client. One of primary, primaryPreferred, secondary, secondaryPreferred, or nearest. Defaults to primary.
readPreferenceTags: Specifies a tag set as a comma-separated list of colon-separated key-value pairs. For example dc:ny,rack:1. Defaults to None.
maxStalenessSeconds: (integer) The maximum estimated length of time a replica set secondary can fall behind the primary in replication before it will no longer be selected for operations. Defaults to -1, meaning no maximum. If maxStalenessSeconds is set, it must be a positive integer greater than or equal to 90 seconds.

See also

Server Selector Example

Authentication:

username: A string.
password: A string.
Although username and password must be percent-escaped in a MongoDB URI, they must not be percent-escaped when passed as parameters. In this example, both the space and slash special characters are passed as-is:
```
MongoClient(username=”user name”, password=”pass/word”)
```
authSource: The database to authenticate on. Defaults to the database specified in the URI, if provided, or to “admin”.
authMechanism: See MECHANISMS for options. If no mechanism is specified, PyMongo automatically uses MONGODB-CR when connected to a pre-3.0 version of MongoDB, SCRAM-SHA-1 when connected to MongoDB 3.0 through 3.6, and negotiates the mechanism to use (SCRAM-SHA-1 or SCRAM-SHA-256) when connected to MongoDB 4.0+.
authMechanismProperties: Used to specify authentication mechanism specific options. To specify the service name for GSSAPI authentication pass authMechanismProperties=’SERVICE_NAME:<service name>’. To specify the session token for MONGODB-AWS authentication pass authMechanismProperties=’AWS_SESSION_TOKEN:<session token>’.

See also

Authentication Examples

TLS/SSL configuration:

tls: (boolean) If True, create the connection to the server using transport layer security. Defaults to False.
tlsInsecure: (boolean) Specify whether TLS constraints should be relaxed as much as possible. Setting tlsInsecure=True implies tlsAllowInvalidCertificates=True and tlsAllowInvalidHostnames=True. Defaults to False. Think very carefully before setting this to True as it dramatically reduces the security of TLS.
tlsAllowInvalidCertificates: (boolean) If True, continues the TLS handshake regardless of the outcome of the certificate verification process. If this is False, and a value is not provided for tlsCAFile, PyMongo will attempt to load system provided CA certificates. If the python version in use does not support loading system CA certificates then the tlsCAFile parameter must point to a file of CA certificates. tlsAllowInvalidCertificates=False implies tls=True. Defaults to False. Think very carefully before setting this to True as that could make your application vulnerable to man-in-the-middle attacks.
tlsAllowInvalidHostnames: (boolean) If True, disables TLS hostname verification. tlsAllowInvalidHostnames=False implies tls=True. Defaults to False. Think very carefully before setting this to True as that could make your application vulnerable to man-in-the-middle attacks.
tlsCAFile: A file containing a single or a bundle of “certification authority” certificates, which are used to validate certificates passed from the other end of the connection. Implies tls=True. Defaults to None.
tlsCertificateKeyFile: A file containing the client certificate and private key. If you want to pass the certificate and private key as separate files, use the ssl_certfile and ssl_keyfile options instead. Implies tls=True. Defaults to None.
tlsCRLFile: A file containing a PEM or DER formatted certificate revocation list. Only supported by python 2.7.9+ (pypy 2.5.1+). Implies tls=True. Defaults to None.
tlsCertificateKeyFilePassword: The password or passphrase for decrypting the private key in tlsCertificateKeyFile or ssl_keyfile. Only necessary if the private key is encrypted. Only supported by python 2.7.9+ (pypy 2.5.1+) and 3.3+. Defaults to None.
tlsDisableOCSPEndpointCheck: (boolean) If True, disables certificate revocation status checking via the OCSP responder specified on the server certificate. Defaults to False.
ssl: (boolean) Alias for tls.
ssl_certfile: The certificate file used to identify the local connection against mongod. Implies tls=True. Defaults to None.
ssl_keyfile: The private keyfile used to identify the local connection against mongod. Can be omitted if the keyfile is included with the tlsCertificateKeyFile. Implies tls=True. Defaults to None.

Read Concern options:

(If not set explicitly, this will use the server default)

readConcernLevel: (string) The read concern level specifies the level of isolation for read operations. For example, a read operation using a read concern level of majority will only return data that has been written to a majority of nodes. If the level is left unspecified, the server default will be used.

Client side encryption options:

(If not set explicitly, client side encryption will not be enabled.)

auto_encryption_opts: A AutoEncryptionOpts which configures this client to automatically encrypt collection commands and automatically decrypt results. See Automatic Client-Side Field Level Encryption for an example.

See also

The MongoDB documentation on

connections

Changed in version 3.11: Added the following keyword arguments and URI options:

tlsDisableOCSPEndpointCheck
directConnection

Changed in version 3.9: Added the retryReads keyword argument and URI option. Added the tlsInsecure keyword argument and URI option. The following keyword arguments and URI options were deprecated:

wTimeout was deprecated in favor of wTimeoutMS.
j was deprecated in favor of journal.
ssl_cert_reqs was deprecated in favor of tlsAllowInvalidCertificates.
ssl_match_hostname was deprecated in favor of tlsAllowInvalidHostnames.
ssl_ca_certs was deprecated in favor of tlsCAFile.
ssl_certfile was deprecated in favor of tlsCertificateKeyFile.
ssl_crlfile was deprecated in favor of tlsCRLFile.
ssl_pem_passphrase was deprecated in favor of tlsCertificateKeyFilePassword.

Changed in version 3.9: retryWrites now defaults to True.

Changed in version 3.8: Added the server_selector keyword argument. Added the type_registry keyword argument.

Changed in version 3.7: Added the driver keyword argument.

Changed in version 3.6: Added support for mongodb+srv:// URIs. Added the retryWrites keyword argument and URI option.

Changed in version 3.5: Add username and password options. Document the authSource, authMechanism, and authMechanismProperties options. Deprecated the socketKeepAlive keyword argument and URI option. socketKeepAlive now defaults to True.

Changed in version 3.0: MongoClient is now the one and only client class for a standalone server, mongos, or replica set. It includes the functionality that had been split into MongoReplicaSetClient: it can connect to a replica set, discover all its members, and monitor the set for stepdowns, elections, and reconfigs.

The MongoClient constructor no longer blocks while connecting to the server or servers, and it no longer raises ConnectionFailure if they are unavailable, nor ConfigurationError if the user’s credentials are wrong. Instead, the constructor returns immediately and launches the connection process on background threads.

Therefore the alive method is removed since it no longer provides meaningful information; even if the client is disconnected, it may discover a server in time to fulfill the next operation.

In PyMongo 2.x, MongoClient accepted a list of standalone MongoDB servers and used the first it could connect to:

MongoClient(['host1.com:27017', 'host2.com:27017'])

A list of multiple standalones is no longer supported; if multiple servers are listed they must be members of the same replica set, or mongoses in the same sharded cluster.

The behavior for a list of mongoses is changed from “high availability” to “load balancing”. Before, the client connected to the lowest-latency mongos in the list, and used it until a network error prompted it to re-evaluate all mongoses’ latencies and reconnect to one of them. In PyMongo 3, the client monitors its network latency to all the mongoses continuously, and distributes operations evenly among those with the lowest latency. See mongos Load Balancing for more information.

The connect option is added.

The start_request, in_request, and end_request methods are removed, as well as the auto_start_request option.

The copy_database method is removed, see the copy_database examples for alternatives.

The MongoClient.disconnect() method is removed; it was a synonym for close().

MongoClient no longer returns an instance of Database for attribute names with leading underscores. You must use dict-style lookups instead:

client['__my_database__']

Not:

client.__my_database__

close()

Cleanup client resources and disconnect from MongoDB.

On MongoDB >= 3.6, 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. If this instance is used again it will be automatically re-opened and the threads restarted unless auto encryption is enabled. A client enabled with auto encryption cannot be used again after being closed; any attempt will raise InvalidOperation.

Changed in version 3.6: End all server sessions created by this client.
c[db_name] || c.db_name

Get the db_name Database on MongoClient c.

Raises InvalidName if an invalid database name is used.
event_listeners

The event listeners registered for this client.

See monitoring for details.
address

(host, port) of the current standalone, primary, or mongos, or None.

Accessing address raises InvalidOperation if the client is load-balancing among mongoses, since there is no single address. Use nodes 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.
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 when MongoReplicaSetClient’s functionality was merged in.
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 when MongoReplicaSetClient’s functionality was merged in.
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.
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.
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..
max_pool_size

The maximum allowable number of concurrent connections to each connected server. Requests to a server will block if there are maxPoolSize outstanding connections to the requested server. Defaults to 100. Cannot be 0.

When a server’s pool has reached max_pool_size, operations for that server block waiting for a socket to be returned to the pool. If waitQueueTimeoutMS is set, a blocked operation will raise ConnectionFailure after a timeout. By default waitQueueTimeoutMS is not set.
min_pool_size

The minimum required number of concurrent connections that the pool will maintain to each connected server. Default is 0.
max_idle_time_ms

The maximum number of milliseconds that a connection can remain idle in the pool before being removed and replaced. Defaults to None (no limit).
nodes

Set of all currently connected servers.

Warning

When connected to a replica set the value of nodes can change over time as MongoClient’s view of the replica set changes. nodes can also be an empty set when MongoClient is first instantiated and hasn’t yet connected to any servers, or a network partition causes it to lose connection to all servers.
max_bson_size

The largest BSON object the connected server accepts in bytes.

If the client is not connected, this will block until a connection is established or raise ServerSelectionTimeoutError if no server is available.
max_message_size

The largest message the connected server accepts in bytes.

If the client is not connected, this will block until a connection is established or raise ServerSelectionTimeoutError if no server is available.
max_write_batch_size

The maxWriteBatchSize reported by the server.

If the client is not connected, this will block until a connection is established or raise ServerSelectionTimeoutError if no server is available.

Returns a default value when connected to server versions prior to MongoDB 2.6.
local_threshold_ms

The local threshold for this instance.
server_selection_timeout

The server selection timeout for this instance in seconds.
codec_options

Read only access to the CodecOptions of this instance.
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.
write_concern

Read only access to the WriteConcern of this instance.

Changed in version 3.0: The write_concern attribute is now read only.
read_concern

Read only access to the ReadConcern of this instance.

New in version 3.2.
start_session(causal_consistency=True, default_transaction_options=None)

Start a logical session.

This method takes the same parameters as SessionOptions. See the client_session module for details and examples.

Requires MongoDB 3.6. It is an error to call start_session() if this client has been authenticated to multiple databases using the deprecated method authenticate().

A ClientSession may only be used with the MongoClient that started it. ClientSession instances are not thread-safe or fork-safe. They can only be used by one thread or process at a time. A single ClientSession cannot be used to run multiple operations concurrently.

Returns: An instance of ClientSession.

New in version 3.6.

Returns:	An instance of `ClientSession`.

list_databases(session=None, \*kwargs*)

Get a cursor over the databases of the connected server.

Parameters:	session (optional): a `ClientSession`. **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`.

New in version 3.6.

list_database_names(session=None)

Get a list of the names of all databases on the connected server.
Parameters:
session (optional): a ClientSession.
New in version 3.6.
database_names(session=None)

DEPRECATED: Get a list of the names of all databases on the connected server.
Parameters:
session (optional): a ClientSession.
Changed in version 3.7: Deprecated. Use list_database_names() instead.

Changed in version 3.6: Added session parameter.
drop_database(name_or_database, session=None)

Drop a database.

Raises TypeError if name_or_database is not an instance of basestring (str in python 3) or Database.
Parameters:
name_or_database: the name of a database to drop, or a Database instance representing the database to drop
session (optional): a ClientSession.
Changed in version 3.6: Added session parameter.

Note

The write_concern of this client is automatically applied to this operation when using MongoDB >= 3.4.

Changed in version 3.4: Apply this client’s write concern automatically to this operation when connected to MongoDB >= 3.4.

Parameters:	session (optional): a `ClientSession`.

Parameters:	session (optional): a `ClientSession`.

Parameters:	name_or_database: the name of a database to drop, or a `Database` instance representing the database to drop session (optional): a `ClientSession`.

get_default_database(default=None, codec_options=None, read_preference=None, write_concern=None, read_concern=None)

Get the database named in the MongoDB connection URI.

>>> uri = 'mongodb://host/my_database'
>>> client = MongoClient(uri)
>>> db = client.get_default_database()
>>> assert db.name == 'my_database'
>>> db = client.get_database()
>>> assert db.name == 'my_database'

Useful in scripts where you want to choose which database to use based only on the URI in a configuration file.

Parameters:

Parameters:	default (optional): the database name to use if no database name was provided in the URI. codec_options (optional): An instance of `CodecOptions`. If `None` (the default) the `codec_options` of this `MongoClient` is used. read_preference (optional): The read preference to use. If `None` (the default) the `read_preference` of this `MongoClient` is used. See `read_preferences` for options. write_concern (optional): An instance of `WriteConcern`. If `None` (the default) the `write_concern` of this `MongoClient` is used. read_concern (optional): An instance of `ReadConcern`. If `None` (the default) the `read_concern` of this `MongoClient` is used.

default (optional): the database name to use if no database name was provided in the URI.
codec_options (optional): An instance of CodecOptions. If None (the default) the codec_options of this MongoClient is used.
read_preference (optional): The read preference to use. If None (the default) the read_preference of this MongoClient is used. See read_preferences for options.
write_concern (optional): An instance of WriteConcern. If None (the default) the write_concern of this MongoClient is used.
read_concern (optional): An instance of ReadConcern. If None (the default) the read_concern of this MongoClient is used.

Changed in version 3.8: Undeprecated. Added the default, codec_options, read_preference, write_concern and read_concern parameters.

Changed in version 3.5: Deprecated, use get_database() instead.

get_database(name=None, codec_options=None, read_preference=None, write_concern=None, read_concern=None)

Get a Database with the given name and options.

Useful for creating a Database with different codec options, read preference, and/or write concern from this MongoClient.

>>> client.read_preference
Primary()
>>> db1 = client.test
>>> db1.read_preference
Primary()
>>> from pymongo import ReadPreference
>>> db2 = client.get_database(
...     'test', read_preference=ReadPreference.SECONDARY)
>>> db2.read_preference
Secondary(tag_sets=None)

Parameters:

Parameters:	name (optional): The name of the database - a string. If `None` (the default) the database named in the MongoDB connection URI is returned. codec_options (optional): An instance of `CodecOptions`. If `None` (the default) the `codec_options` of this `MongoClient` is used. read_preference (optional): The read preference to use. If `None` (the default) the `read_preference` of this `MongoClient` is used. See `read_preferences` for options. write_concern (optional): An instance of `WriteConcern`. If `None` (the default) the `write_concern` of this `MongoClient` is used. read_concern (optional): An instance of `ReadConcern`. If `None` (the default) the `read_concern` of this `MongoClient` is used.

name (optional): The name of the database - a string. If None (the default) the database named in the MongoDB connection URI is returned.
codec_options (optional): An instance of CodecOptions. If None (the default) the codec_options of this MongoClient is used.
read_preference (optional): The read preference to use. If None (the default) the read_preference of this MongoClient is used. See read_preferences for options.
write_concern (optional): An instance of WriteConcern. If None (the default) the write_concern of this MongoClient is used.
read_concern (optional): An instance of ReadConcern. If None (the default) the read_concern of this MongoClient is used.

Changed in version 3.5: The name parameter is now optional, defaulting to the database named in the MongoDB connection URI.

server_info(session=None)

Get information about the MongoDB server we’re connected to.
Parameters:
session (optional): a ClientSession.
Changed in version 3.6: Added session parameter.

Parameters:	session (optional): a `ClientSession`.

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)

Watch changes on this cluster.

Performs an aggregation with an implicit initial $changeStream stage and returns a ClusterChangeStream cursor which iterates over changes on all databases on this cluster.

Introduced in MongoDB 4.0.

with client.watch() as stream:
    for change in stream:
        print(change)

The ClusterChangeStream iterable blocks until the next change document is returned or an error is raised. If the next() method encounters a network error when retrieving a batch from the server, it will automatically attempt to recreate the cursor such that no change events are missed. Any error encountered during the resume attempt indicates there may be an outage and will be raised.

try:
    with client.watch(
            [{'$match': {'operationType': 'insert'}}]) as stream:
        for insert_change in stream:
            print(insert_change)
except pymongo.errors.PyMongoError:
    # The ChangeStream encountered an unrecoverable error or the
    # resume attempt failed to recreate the cursor.
    logging.error('...')

For a precise description of the resume process see the change streams specification.

Parameters:

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 to pass as an option 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.
Returns:	A `ClusterChangeStream` cursor.

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 to pass as an option 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.

Returns:

A ClusterChangeStream cursor.

Changed in version 3.9: Added the start_after parameter.

New in version 3.7.

See also

The MongoDB documentation on

changeStreams

close_cursor(cursor_id, address=None)

DEPRECATED - Send a kill cursors message soon with the given id.

Raises TypeError if cursor_id is not an instance of (int, long). What closing the cursor actually means depends on this client’s cursor manager.

This method may be called from a Cursor destructor during garbage collection, so it isn’t safe to take a lock or do network I/O. Instead, we schedule the cursor to be closed soon on a background thread.

Parameters:	cursor_id: id of cursor to close address (optional): (host, port) pair of the cursor’s server. If it is not provided, the client attempts to close the cursor on the primary or standalone, or a mongos server.

Changed in version 3.7: Deprecated.

Changed in version 3.0: Added address parameter.

kill_cursors(cursor_ids, address=None)

DEPRECATED - Send a kill cursors message soon with the given ids.

Raises TypeError if cursor_ids is not an instance of list.

Parameters:	cursor_ids: list of cursor ids to kill address (optional): (host, port) pair of the cursor’s server. If it is not provided, the client attempts to close the cursor on the primary or standalone, or a mongos server.

Changed in version 3.3: Deprecated.

Changed in version 3.0: Now accepts an address argument. Schedules the cursors to be closed on a background thread instead of sending the message immediately.

set_cursor_manager(manager_class)

DEPRECATED - Set this client’s cursor manager.

Raises TypeError if manager_class is not a subclass of CursorManager. A cursor manager handles closing cursors. Different managers can implement different policies in terms of when to actually kill a cursor that has been closed.
Parameters:
manager_class: cursor manager to use
Changed in version 3.3: Deprecated, for real this time.

Changed in version 3.0: Undeprecated.
is_locked

DEPRECATED: Is this server locked? While locked, all write operations are blocked, although read operations may still be allowed. Use unlock() to unlock.

Deprecated. Users of MongoDB version 3.2 or newer can run the currentOp command directly with command():
```
is_locked = client.admin.command('currentOp').get('fsyncLock')
```
Users of MongoDB version 2.6 and 3.0 can query the “inprog” virtual collection:
```
is_locked = client.admin["$cmd.sys.inprog"].find_one().get('fsyncLock')
```
Changed in version 3.11: Deprecated.
fsync(\*kwargs*)

DEPRECATED: Flush all pending writes to datafiles.
- Optional parameters can be passed as keyword arguments:
  - lock: If True lock the server to disallow writes.
  - async: If True don’t block while synchronizing.
  - session (optional): a ClientSession.
Note

Starting with Python 3.7 async is a reserved keyword. The async option to the fsync command can be passed using a dictionary instead:
```
options = {'async': True}
client.fsync(**options)
```
Deprecated. Run the fsync command directly with command() instead. For example:
```
client.admin.command('fsync', lock=True)
```
Changed in version 3.11: Deprecated.

Changed in version 3.6: Added session parameter.

Warning

async and lock can not be used together.

Warning

MongoDB does not support the async option on Windows and will raise an exception on that platform.
unlock(session=None)

DEPRECATED: Unlock a previously locked server.
Parameters:
session (optional): a ClientSession.
Deprecated. Users of MongoDB version 3.2 or newer can run the fsyncUnlock command directly with command():
```
client.admin.command('fsyncUnlock')
```
Users of MongoDB version 2.6 and 3.0 can query the “unlock” virtual collection:
```
client.admin["$cmd.sys.unlock"].find_one()
```
Changed in version 3.11: Deprecated.

Changed in version 3.6: Added session parameter.

Parameters:	manager_class: cursor manager to use

Parameters:	session (optional): a `ClientSession`.

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