Scribe For Ruby Made Easy

To use Scribe, you usually have to use Apache Thrift to generate Ruby code from generic *.thrift files.

This gem tries to alleviate that slight annoyance and package everything you need to communicate with Scribe.

It also contains a some "extras" that alleviate a few gotchas I found while creating a Scribe consumer/server.

Installation

Bundler

Add to Gemfile and run bundle install:

gem 'scribe-rb'

Without Bundler

Install the gem:

gem install scribe-rb

Require it explicitly in your scripts:

require "rubygems"
require "scribe-rb"

Producer (Client)

# Setup
socket = Thrift::Socket.new('localhost', 1463)

transport = Thrift::FramedTransport.new(socket)
transport.open

protocol = Thrift::BinaryProtocol.new(transport, false)
client   = Scribe::Client.new(protocol)

# Logging
log_entry = LogEntry.new(:category => 'default', :message => 'This is a test message')
client.Log([log_entry])

# Teardown
transport.close

Consumer (Server)

# Define a handler that inherits from FacebookService::BaseHandler
class MyScribeHandler < FacebookService::BaseHandler
  def Log(messages)
    # Process the array of LogEntry instances passed
    messages.each do |message|
      puts "#{message.category}: #{message.message}"
    end

    # If messages were processed correctly, return `ResultCode::OK`
    #
    # To tell the Scribe producer/broker to resend messages later (e.g.,
    # because this process is under too much load), return
    # `ResultCode::TRY_LATER`

    # Must return `ResultCode::OK` or `ResultCode::TRY_LATER`
    ResultCode::OK
  end
end

# Setup
handler   = MyScribeHandler.new("My Scribe Handler")
processor = Scribe::Processor.new(handler)

transport = Thrift::ServerSocket.new(5678) # 5678 is port number

transportFactory = Thrift::FramedTransportFactory.new
protocolFactory  = Thrift::NonStrictBinaryProtocolFactory.new

# There are multiple options for server type
# * [Thrift::SimpleServer](http://rubydoc.info/gems/thrift/0.7.0/Thrift/SimpleServer): single threaded server (simplest)
# * [Thrift::ThreadedServer](http://rubydoc.info/gems/thrift/0.7.0/Thrift/ThreadedServer): server that spawns a thread to handle messages
# * [Thrift::ThreadPoolServer](http://rubydoc.info/gems/thrift/0.7.0/Thrift/ThreadPoolServer): server that uses a constant number of threads as workers
# * [Thrift::NonblockingServer](http://rubydoc.info/gems/thrift/0.7.0/Thrift/NonblockingServer): server that uses non-blocking I/O
server = Thrift::SimpleServer.new(processor, transport, transportFactory, protocolFactory)
server.serve

QueuedLogMessageHandler

It is not advisable to do any expensive operation within the Log method. If a response code is not received by Scribe within a few seconds (by default), Scribe will assume the connection is dead. If it is configured with a buffer store, the same messages will be sent over and over again, potentially failing each time.

To alleviate this, scribe-rb includes the FacebookService::QueuedLogMessageHandler class which implements a Log method that adds messages to a thread-safe in-memory queue. This happens quickly and allows expensive operations to occur in a different thread that does not block Scribe.

An example usage:

handler = FacebookService::QueuedLogMessageHandler.new("My Scribe Handler")
handler.message_limit = 100000 # accept up to 100000 messages at a time; if set to nil (default), there is no limit

Thread.new do
  while message = handler.queue.pop # will block until a message is available
    # Do some expensive operation with `message`
  end
end

# ...
server = Thrift::SimpleServer.new(processor, transport, transportFactory, protocolFactory)
server.serve

Custom Queue Implementation

A custom queue object (e.g., circular_queue) can be specified by passing a :queue option to the constructor.

handler = FacebookService::QueuedLogMessageHandler.new("My Scribe Handler",
                                                       :queue => CircularQueue.new(50000))

The custom queue object must respond to the push and size messages.

Hat Tips

• Installing and Using Scribe with Ruby on Mac OS
• Ruby Web-Services with Facebook’s Thrift

License

Copyright (c) 2011 Highgroove Studios

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.