How can I disable MongoDB log messages in console?

I have this little test script:

require 'mongo'

mongo_client = Mongo::Client.new(['127.0.0.1:27017'], :database => 'test')
mongo_client[:collection].insert_one({a: 1})

An this is the console output:

$ ruby test.rb
D, [2015-05-17T21:12:05.504986 #25257] DEBUG -- : MONGODB | Adding 127.0.0.1:27017 to the cluster. | runtime: 0.0212ms
D, [2015-05-17T21:12:05.531238 #25257] DEBUG -- : MONGODB | COMMAND | namespace=admin.$cmd selector={:ismaster=>1} flags=[] limit=-1 skip=0 project=nil | runtime: 24.5481ms
D, [2015-05-17T21:12:05.554532 #25257] DEBUG -- : MONGODB | COMMAND | namespace=test.$cmd selector={:insert=>"collection", :documents=>[{:a=>1, :_id=><BSON::ObjectId:0x21935660 data=5558e80553657262a9000000>}], :writeConcern=>{:w=>1}, :ordered=>true} flags=[] limit=-1 skip=0 project=nil | runtime: 21.1718ms

I want to disable those log messages, I don't want a dirty STDOUT. I didn't found any option for this in the ruby driver, and also I've tried to edit /etc/mongod.conf with these directives (but it didn't fix it):

verbose = false
diaglog = 0

Any idea? I don't know what else I can try!

Solution

This logging is coming from the Ruby Mongo driver. The default logging level seems to be Logger::DEBUG. Change it to something higher to disable the debug output:

Mongo::Logger.logger.level = Logger::FATAL

To make the driver log to a logfile instead:

Mongo::Logger.logger       = Logger.new('mongo.log')
Mongo::Logger.logger.level = Logger::INFO

Note that if you're using the Mongoid ODM, then you may want to adjust logging there too:

Mongoid.logger       = Logger.new('mongoid.log')
Mongoid.logger.level = Logger::INFO

For Rails + Mongoid in application.rb:

config.mongoid.logger = Logger.new(Rails.root + '/log/mongoid.log', :warn)

# ...or change the logging level without a new file destination
config.mongoid.logger.level = Logger::INFO