MongoDB

You can create datasources to expose data in MongoDB databases as services using the WSO2 Data Services Server. You can select MongoDB as the datasource type at the time a datasource is created. That is, the MongoDB specific options will be available as shown below.

The fields available for MongoDB data source type are as follows:

• Servers: A comma separated list of server hosts and ports where the database is running. E.g.: "localhost" - "125.10.5.3, 125.10.5.4" - "192.168.3.1:27017, 192.168.3.2:27017"
• Database Name:  The name of the database to which you want to connect.

• Write Concern: The write concern value to control the write behaviour as well as exception raising on error conditions. The following options are available.

  Option	Description
  FSYNC_SAFE	Exceptions are raised for network issues, and server errors. The write operation waits for the server to flush the data to disk.
  NONE	No exceptions are raised, even for network issues.
  NORMAL	Exceptions are raised for network issues, but not server errors.
  REPLICAS_SAFE	Exceptions are raised for network issues, and server errors; waits for at least 2 servers for the write operation.
  SAFE	Exceptions are raised for network issues, and server errors; waits on a server for the write operation.

• Read Preference: The read preference value which describes how MongoDB clients route read operations to members of a replica set. It has the following options.

  Option	Description
  PRIMARY	Default mode. All operations read from the current replica set primary.
  SECONDARY	All operations read from the secondary members of the replica set.

• Auto Connect Retry: Controls whether or not to connect. That is, the system retries to connect automatically.
  
• Connection Timeout: Connection timeout in milliseconds. 0 is default and infinite.
  
• Max. Wait: Max wait time of a blocking thread for a connection.
• Socket Timeout: Socket timeout value. 0 is default and infinite.
  
• Connections per Host: If the number of connections allowed per host is exceeded, further connections will be blocked.
  
• Threads Allowed to Block For Connection Multiplier: The value in this field, multiplied by the connections per host, gives the maximum number of threads that may be waiting for a connection to become available from the pool. All further threads will get an exception. For example, if connections per host is 10 and the 'threads allowed to block for connection multiplier' is 5, up to 50 threads can wait for a connection.

To write a query to this datasource, see Writing Data Service Queries.

Also, see a demonstration of service enabling a Web resource in MongoDB Sample.