plugin to use MongoDB as backend.

tested in ubuntu 10.04, ubuntu 10.10 and FreeBSD 11.1

configuration:

in your /etc/rsyslog.conf, together with other modules:
$ModLoad ommongodb # provides mongodb support
*.*     action(type="ommongodb" db="..." collection="..." template="...")

Note: if no template is specified, a default schema will be used. That schema
contains proper data types. However, if a template is specified, only strings
are supported. This is a restriction of the rsyslog v6 core engine. This 
changed in v7.

If templates are used, it is suggested to use list-based templates. Constants
can ONLY be inserted with list-based templates, as only these provide the
capability to specify a field name (outname parameter).

A very basic example is:

*.*     action(type="ommongodb" db="logs" collection="syslog")

A more complex example:
*.*     action(type="ommongodb" uristr="mongodb://vulture:9091,vulture2:9091/?replicaset=Vulture&ssl=true" ssl_cert="/var/db/mongodb/mongod.pem" ssl_ca="/var/db/mongodb/ca.pem" db="logs" collection="syslog" allowed_error_codes="11000")

Please see the script clean-mongo-syslog for an example of how to
purge old records from MongoDB using PyMongo.  It can be run
daily or weekly from cron.

You may also wish to index some or all of the columns in MongoDB.
The following statements may help to create the indexes:

To see the existing indexes:

  db.syslog.getIndexes()

To create them:

  db.syslog.ensureIndex( { sys : 1 } )
  db.syslog.ensureIndex( { time : 1 } )
  db.syslog.ensureIndex( { syslog_fac : 1 } )
  db.syslog.ensureIndex( { syslog_sever : 1 } )
  db.syslog.ensureIndex( { syslog_tag : 1 } )
  db.syslog.ensureIndex( { procid : 1 } )
  db.syslog.ensureIndex( { pid : 1 } )