RightSupport is a library of reusable, unit- and functional-tested Ruby code that RightScale has found broadly useful.

What Does It Do?

Logging

SystemLogger is a rewrite of the seattle.rb SyslogLogger class that features the following improvements:

  • Contains several bugfixes vs. SyslogLogger 1.4.0

  • Inherits from standard Ruby Logger class for guaranteed compatibility

  • Can be configured with options about how to handle newlines, ANSI escape codes, etc

It is very similar to SystemLogger, with a few differences (e.g. it is a child class of Logger instead of merely being duck-type compatible). You use it as follows.

@logger = SystemLogger.new('my_cool_app', :split=>true, :color=>false)
@logger.info "Hello world\nThis will appear on separate lines\nand without \e[33;0mbeautiful colors"

CustomLogger is a Rack middleware that allows a Rack app to use any log sink it wishes. The stock Rack logger middleware is inflexible and gives the end user no control over which logger is used or where the log entries go.

require 'right_support/rack/custom_logger'

my_logger = MyAwesomeLogger.new
use RightSupport::Rack::CustomLogger, Logger::INFO, my_logger

String Manipulation

StringExtensions contains String#camelize, which is only defined if the ActiveSupport gem cannot be loaded. It also has some RightScale-specific methods:

  • String#snake_case

  • String#to_const

  • String#to_const_path

Net::StringEncoder applies and removes URL-escape, base64 and other encodings.

Input Validation

Validation contains several format-checkers that can be used to validate your web app's models before saving, check for preconditions in your controllers, and so forth.

You can use it as a mixin by including the appropriate child module of RightSupport::Validation.

class AwesomenessGenerator < ActiveRecord::Base
  include RightSupport::Validation::OpenSSL

  before_save do |record|
    errors[:foo] = 'Hey, that's not a key!' unless pem_public_key?(record.foo)
  end
end

But you really don't want to do that, do you? Instead, you want to call the module methods of RightSupport::Validation, which contains all of the same mixin methods, but does not pollute the dispatch table of your application classes.

the_key = STDIN.read
raise ArgumentError unless RightSupport::Validation.ssh_public_key?(the_key)

Client-Side Load Balancer

RequestBalancer randomly chooses endpoints for a network request, which lets you perform easy client-side load balancing:

include RightSupport::Net

urls = ['http://localhost', 'http://otherhost']
RequestBalancer.request(urls, :fatal=>RestClient::ResourceNotFound) do |url|
  REST.get(url)
end

The balancer will keep trying requests until one of them succeeds without throwing any exceptions. (NB: a nil return value counts as success!!)

HTTP Client

We provide a very thin wrapper around the rest-client gem that enables simple but robust rest requests with a timeout, headers, etc.

HTTPClient is interface-compatible with the RestClient module, but allows an optional timeout to be specified as an extra parameter.

# Create a wrapper object
@client = RightSupport::Net::HTTPClient.new

# Default timeout is 5 seconds
@client.get('http://localhost')

# Make sure the HTTPClient request fails after 1 second so we can report an error
# and move on!
@client.get('http://localhost', {:headers => {'X-Hello'=>'hi!'}, :timeout => 1)}

Statistics Gathering

Profile your compute-heavy and network activities using a Stats::Activity counter.

stats = RightSupport::Stats::Activity.new

puts 'enter 5 lines:'
5.times do
  stats.update(:read_input)
  line = STDIN.readline
  stats.finish
end

puts "Only %.1f lines/sec? You are a slow typist!" % [stats.avg_rate]