Class: MongoProxy

Inherits:
Object
  • Object
show all
Defined in:
lib/mongo-proxy/proxy.rb

Overview

This class uses em-proxy to help listen to MongoDB traffic, with some parsing and filtering capabilities that allow you to enforce a read-only mode, or use your own arbitrary logic.

Constant Summary collapse

VERSION = 
'1.0.1'

Instance Method Summary collapse

Constructor Details

#initialize(config = nil) ⇒ MongoProxy

Returns a new instance of MongoProxy.



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# File 'lib/mongo-proxy/proxy.rb', line 15

def initialize(config = nil)
  # default config values
  @config = {
    :client_host => '127.0.0.1', # Set the host to bind the proxy socket on.
    :client_port => 29017,       # Set the port to bind the proxy socket on.
    :server_host => '127.0.0.1', # Set the backend host which we proxy.
    :server_port => 27017,       # Set the backend port which we proxy.
    :motd => nil,                # Set a message-of-the-day to display to clients when they connect. nil for none.
    :read_only => false,         # Prevent any traffic that writes to the database.
    :verbose => false,           # Print out MongoDB wire traffic.
    :logger => nil,              # Use this object as the logger instead of creating one.
    :debug => false              # Print log lines in a more human-readible format.
  }
  @front_callbacks = []
  @back_callbacks = []

  # apply argument config to the default values
  (config || []).each do |k, v|
    if @config.include?(k)
      @config[k] = v
    else
      raise "Unrecognized configuration value: #{k}"
    end
  end

  # debug implies verbose
  @config[:verbose] = true if @config[:debug]

  # Set up the logger for mongo proxy. Users can also pass their own
  # logger in with the :logger config value.
  unless @config[:logger]
    @config[:logger] = Logger.new(STDOUT)
    @config[:logger].level = (@config[:verbose] ? Logger::DEBUG : Logger::WARN)

    if @config[:debug]
      @config[:logger].formatter = proc do |_, _, _, msg|
        if msg.is_a?(Hash)
          "#{JSON::pretty_generate(msg)}\n\n"
        else
          "#{msg}\n\n"
        end
      end
    end
  end

  unless port_open?(@config[:server_host], @config[:server_port])
    raise "Could not connect to MongoDB server at #{@config[:server_host]}.#{@config[:server_port]}"
  end

  @log = @config[:logger]
  @auth = AuthMongo.new(@config)
end

Instance Method Details

#add_callback_to_back(&block) ⇒ Object 



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# File 'lib/mongo-proxy/proxy.rb', line 88

def add_callback_to_back(&block)
  @back_callbacks << block
end

#add_callback_to_front(&block) ⇒ Object 



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# File 'lib/mongo-proxy/proxy.rb', line 84

def add_callback_to_front(&block)
  @front_callbacks.insert(0, block)
end

#start ⇒ Object 



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# File 'lib/mongo-proxy/proxy.rb', line 68

def start
  # em proxy launches a thread, this is the error handler for it
  EM.error_handler do |e|
    @log.error [e.inspect, e.backtrace.first]
    raise e
  end

  # kick off em-proxy
  Proxy.start({
      :host => @config[:client_host],
      :port => @config[:client_port],
      :debug => false
    },
    &method(:callbacks))
end