cptn-log.gemspec

Gem::Specification.new do |s|
  s.name        = 'cptn-log'
  s.version     = '0.0.2'
  s.platform    = Gem::Platform::RUBY
  s.author      = 'Kevin Melchert'
  s.email       = 'kevin.melchert@gmail.com'
  s.summary     = 'MongoDB Logger.'
  s.description = 'MongoDB Logger.'
 
  s.files         = ['cptn-log.rb']
  s.require_path  = '.'
end

cptn-log.rb

module Captain
  class Logbook
    def initialize(database, name: 'cptn.log', size: 5242880, max: nil)
      @db, @name, @size, @max = database, name, size, max
    end
    
    %i(debug info warn error fatal).each do |level|
      define_method(level) { |msg, extra={}| log(level, msg, extra) }
    end

    def head(n=20)
      find(n, Mongo::Index::ASCENDING)
    end
        
    def tail(n=20)
      find(n, Mongo::Index::DESCENDING)
    end

    def clear
      collection.drop
    end

    private
    
    def log(level, message, extra = {})
      collection.insert_one({ l: level.to_s, m: message.to_s, x: extra })
    end
        
    def find(n, order)
      collection.find.sort({"$natural" => order}).limit(n)
    end
    
    def collection
      @db.collection collection_name, capped: true, size: @size, max: @max
    end
    
    def collection_name
      @name.respond_to?(:call) ? @name.call : @name
    end
  end
end

usage.rb

client = Mongo::Client.new(['127.0.0.1:27017'])
logger = Captain::Logbook.new(client['test'], name: -> { "cptn.log.#{Time.now.utc.strftime('%Y.%m.%d.%H')}" })