The rocket-fast system for log processing

ommongodb: MongoDB Output Module

Module Name:    ommongodb

Author:Rainer Gerhards <>


This module provides native support for logging to MongoDB.

Action Parameters:

Note: parameter names are case-insensitive.

  • uristr MongoDB connexion string, as defined by the MongoDB String URI Format (See: If uristr is defined, following directives will be ignored: server, serverport, uid, pwd.
  • ssl_cert Absolute path to the X509 certificate you want to use for TLS client authentication. This is optional.
  • ssl_ca Absolute path to the trusted X509 CA certificate that signed the mongoDB server certificate. This is optional.
  • server (deprecated, use “uristr” instead) Name or address of the MongoDB server
  • serverport (deprecated, use “uristr” instead) Permits to select a non-standard port for the MongoDB server. The default is 0, which means the system default port is used. There is no need to specify this parameter unless you know the server is running on a non-standard listen port.
  • db Database to use
  • collection Collection to use
  • uid (deprecated, use “uristr” instead) logon userid used to connect to server. Must have proper permissions.
  • pwd (decrecated, use “uristr” instead) the user’s password
  • template Template to use when submitting messages.

Note rsyslog contains a canned default template to write to the MongoDB. It will be used automatically if no other template is specified to be used. This template is:

template(name="BSON" type="string" string="\\"sys\\" : \\"%hostname%\\",
\\"time\\" : \\"%timereported:::rfc3339%\\", \\"time\_rcvd\\" :
\\"%timegenerated:::rfc3339%\\", \\"msg\\" : \\"%msg%\\",
\\"syslog\_fac\\" : \\"%syslogfacility%\\", \\"syslog\_server\\" :
\\"%syslogseverity%\\", \\"syslog\_tag\\" : \\"%syslogtag%\\",
\\"procid\\" : \\"%programname%\\", \\"pid\\" : \\"%procid%\\",
\\"level\\" : \\"%syslogpriority-text%\\"")

This creates the BSON document needed for MongoDB if no template is specified. The default schema is aligned to CEE and project lumberjack. As such, the field names are standard lumberjack field names, and not rsyslog property names. When specifying templates, be sure to use rsyslog property names as given in the table. If you would like to use lumberjack-based field names inside MongoDB (which probably is useful depending on the use case), you need to select fields names based on the lumberjack schema. If you just want to use a subset of the fields, but with lumberjack names, you can look up the mapping in the default template. For example, the lumberjack field “level” contains the rsyslog property “syslogpriority-text”.


The following sample writes all syslog messages to the database “syslog” and into the collection “log” on The server is being accessed under the account of “user” with password “pwd”. Please note that this syntax is deprecated by the “uristr” directive, as shown below.

       server="" db="syslog" collection="log"
       uid="user" pwd="pwd")

Another sample that uses the new “uristr” directives to connect to a TLS mongoDB server with TLS and client authentication.

      db="logs" collection="syslog")