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- Connection String URI Format
Connection String URI Format¶
This document describes the URI format for defining connections between applications and MongoDB instances in the official MongoDB drivers.
Standard Connection String Format¶
This section describes the standard format of the MongoDB connection URI used to connect to a MongoDB database server. The format is the same for all official MongoDB drivers. For a list of drivers and links to driver documentation, see MongoDB Drivers and Client Libraries.
The following is the standard URI connection scheme:
The components of this string are:
mongodb://
A required prefix to identify that this is a string in the standard connection format.
username:password@
Optional. If specified, the client will attempt to log in to the specific database using these credentials after connecting to the
mongod
instance.host1
This the only required part of the URI. It identifies a server address to connect to. It identifies either a hostname, IP address, or UNIX domain socket.
:port1
Optional. The default value is
:27017
if not specified.hostX
Optional. You can specify as many hosts as necessary. You would specify multiple hosts, for example, for connections to replica sets.
:portX
Optional. The default value is
:27017
if not specified./database
Optional. The name of the database to authenticate if the connection string includes authentication credentials in the form of
username:password@
. If/database
is not specified and the connection string includes credentials, the driver will authenticate to theadmin
database.?options
Connection specific options. See Connection String Options for a full description of these options.
If the connection string does not specify a database/ you must specify a slash (i.e.
/
) between the lasthostN
and the question mark that begins the string of options.
Example
To describe a connection to a replica set named test
,
with the following mongod
hosts:
db1.example.net
on port27017
anddb2.example.net
on port2500
.
You would use a connection string that resembles the following:
Connection String Options¶
This section lists all connection options used in the Standard Connection String Format.
Connection options are pairs in the following form: name=value
. The
value
is always case sensitive. Separate options with the ampersand
(i.e. &
) character. In the following example, a connection uses the
replicaSet
and connectTimeoutMS
options:
Semi-colon separator for connection string arguments
To provide backwards compatibility, drivers currently accept
semi-colons (i.e. ;
) as option separators.
Replica Set Option¶
-
uri.
replicaSet
¶ Specifies the name of the replica set, if the
mongod
is a member of a replica set.When connecting to a replica set it is important to give a seed list of at least two
mongod
instances. If you only provide the connection point of a singlemongod
instance, and omit thereplicaSet
, the client will create a standalone connection.
Connection Options¶
-
uri.
ssl
¶ true
: Initiate the connection with TLS/SSL.false
: Initiate the connection without TLS/SSL.The default value is
false
.Note
The
ssl
option is not supported by all drivers. See your driver documentation and the Configure mongod and mongos for TLS/SSL document.
Connection Pool Options¶
Most drivers implement some kind of connection pooling handle this for you behind the scenes. Some drivers do not support connection pools. See your driver documentation for more information on the connection pooling implementation. These options allow applications to configure the connection pool when connecting to the MongoDB deployment.
-
uri.
maxPoolSize
¶ The maximum number of connections in the connection pool. The default value is
100
.
-
uri.
minPoolSize
¶ The minimum number of connections in the connection pool. The default value is
0
.Note
The
minPoolSize
option is not supported by all drivers. For information on your driver, see the drivers documentation.
-
uri.
maxIdleTimeMS
¶ The maximum number of milliseconds that a connection can remain idle in the pool before being removed and closed.
This option is not supported by all drivers.
-
uri.
waitQueueMultiple
¶ A number that the driver multiples the
maxPoolSize
value to, to provide the maximum number of threads allowed to wait for a connection to become available from the pool. For default values, see the MongoDB Drivers and Client Libraries documentation.
-
uri.
waitQueueTimeoutMS
¶ The maximum time in milliseconds that a thread can wait for a connection to become available. For default values, see the MongoDB Drivers and Client Libraries documentation.
Write Concern Options¶
Write concern describes the kind of assurances
that the mongod
and the driver provide to the application
regarding the success and durability of the write operation. For a
full explanation of write concern and write operations in general, see
Write Concern:
-
uri.
w
¶ Defines the level and kind of write concern. This option can take either a number or a string as a value.
Option Type Description 0
number The driver will not acknowledge write operations but will pass or handle any network and socket errors that it receives to the client.
You can specify the write concern both in the connection string and as a parameter to method calls like
insert
orupdate
. If the write concern is specified in both places, the method parameter overrides the connection-string setting.1
number Provides basic acknowledgment of write operations. By specifying 1
, you require that a standalonemongod
instance, or the primary for replica sets, acknowledge all write operations. For drivers released after the default write concern change, this is the default write concern setting.majority
string For replica sets, if you specify the special majority
value tow
option, write operations will only return successfully after a majority of the configured replica set members have acknowledged the write operation.n
number For replica sets, if you specify a number n
greater than 1, operations with this write concern return only aftern
members of the set have acknowledged the write. If you setn
to a number that is greater than the number of available set members or members that hold data, MongoDB will wait, potentially indefinitely, for these members to become available.tags
string For replica sets, you can specify a tag set to require that all members of the set that have these tags configured return confirmation of the write operation. See Replica Set Tag Set Configuration for more information.
-
uri.
wtimeoutMS
¶ The time in milliseconds to wait for replication to succeed, as specified in the
w
option, before timing out. WhenwtimeoutMS
is0
, write operations will never time out.
-
uri.
journal
¶ Controls whether write operations will wait until the
mongod
acknowledges the write operations and commits the data to the on disk journal.Option Type Description true
Boolean Enables journal commit acknowledgment write concern. Equivalent to specifying a write concern with the j
option enabled.false
Boolean Does not require that mongod
commit write operations to the journal before acknowledging the write operation. This is the default option for thejournal
parameter.If you set
journal
totrue
, and specify aw
value less than 1,journal
prevails.Changed in version 2.6: If you set
journal
to true, and themongod
does not have journaling enabled, as withstorage.journal.enabled
, then MongoDB will error. In previous versions, MongoDB would provide basic receipt acknowledgment (i.e.w:1
), ignorejournal
, and include ajnote
field in its return document.
Read Preference Options¶
Read preferences describe the behavior of read operations with regards to replica sets. These parameters allow you to specify read preferences on a per-connection basis in the connection string:
-
uri.
readPreference
¶ Specifies the replica set read preference for this connection. The read preference values are the following:
For descriptions of each value, see Read Preference Modes.
The default value is
primary
, which sends all read operations to the replica set’s primary.
-
uri.
readPreferenceTags
¶ Specifies a tag set as a comma-separated list of colon-separated key-value pairs. For example:
To specify a list of tag sets, use multiple
readPreferenceTags
. The following specifies two tag sets and an empty tag set:Order matters when using multiple
readPreferenceTags
.
Authentication Options¶
-
uri.
authSource
¶ New in version 2.4.
Specify the database name associated with the user’s credentials, if the users collection do not exist in the database where the client is connecting.
authSource
defaults to the database specified in the connection string.For authentication mechanisms that delegate credential storage to other services, the
authSource
value should be$external
as with thePLAIN
(LDAP) andGSSAPI
(Kerberos) authentication mechanisms.MongoDB will ignore
authSource
values if the connection string specifies no user name.
-
uri.
authMechanism
¶ New in version 2.4.
Changed in version 2.6: Support for the
PLAIN
andMONGODB-X509
authentication mechanisms.Specify the authentication mechanism that MongoDB will use to authenticate the connection. Possible values include:
- MONGODB-CR
- MONGODB-X509
- GSSAPI
- PLAIN
Only MongoDB Enterprise
mongod
andmongos
instances provideGSSAPI
(Kerberos) andPLAIN
(LDAP) mechanisms. To useMONGODB-X509
, you must have TLS/SSL Enabled.See Authentication for more information about the authentication system in MongoDB. Also consider Use x.509 Certificates to Authenticate Clients for more information on x509 authentication.
-
uri.
gssapiServiceName
¶ Set the Kerberos service name when connecting to Kerberized MongoDB instances. This value must match the service name set on MongoDB instances.
gssapiServiceName
defaults tomongodb
for all clients and for MongoDB instance. If you changesaslServiceName
setting on a MongoDB instance, you will need to setgssapiServiceName
to the same value.
Miscellaneous Configuration¶
-
uri.
uuidRepresentation
¶ Option Description standard
The standard binary representation. csharpLegacy
The default representation for the C# driver. javaLegacy
The default representation for the Java driver. pythonLegacy
The default representation for the Python driver. For the default, see the drivers documentation for your driver.
Note
Not all drivers support the
uuidRepresentation
option. For information on your driver, see the drivers documentation.
Examples¶
The following provide example URI strings for common connection targets.
Database Server Running Locally¶
The following connects to a database server running locally on the default port:
admin
Database¶
The following connects and logs in to the admin
database as user
sysop
with the password moon
:
records
Database¶
The following connects and logs in to the records
database as user
sysop
with the password moon
:
UNIX Domain Socket¶
The following connects to a UNIX domain socket:
Note
Not all drivers support UNIX domain sockets. For information on your driver, see the drivers documentation.
Replica Set with Members on Different Machines¶
The following connects to a replica set with two members, one on
db1.example.net
and the other on db2.example.net
:
Replica Set with Members on localhost
¶
The following connects to a replica set with three members running on localhost
on
ports 27017
, 27018
, and 27019
:
Replica Set with Read Distribution¶
The following connects to a replica set with three members and distributes reads to the secondaries:
Replica Set with a High Level of Write Concern¶
The following connects to a replica set with write concern configured to wait for replication to succeed on at least two members, with a two-second timeout.