Module: Emissary

Defined in:
lib/emissary/agent.rb,
lib/emissary.rb,
lib/emissary/daemon.rb,
lib/emissary/errors.rb,
lib/emissary/logger.rb,
lib/emissary/server.rb,
lib/emissary/message.rb,
lib/emissary/identity.rb,
lib/emissary/operator.rb,
lib/emissary/agent/gem.rb,
lib/emissary/agent/file.rb,
lib/emissary/agent/ping.rb,
lib/emissary/agent/test.rb,
lib/emissary/gem_helper.rb,
lib/emissary/agent/error.rb,
lib/emissary/agent/mysql.rb,
lib/emissary/agent/proxy.rb,
lib/emissary/agent/stats.rb,
lib/emissary/identity/ec2.rb,
lib/emissary/identity/unix.rb,
lib/emissary/operator/amqp.rb,
lib/emissary/agent/emissary.rb,
lib/emissary/agent/rabbitmq.rb

Overview

Copyright 2010 The New York Times

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

Defined Under Namespace

Modules: OperatorStatistics, ServerController Classes: Agent, Daemon, Error, GemHelper, Identity, Logger, Message, NetworkEncapsulatedError, Operator, Server, TrackingError

Constant Summary collapse

LIBPATH =

:stopdoc:

File.expand_path(File.dirname(File.expand_path(__FILE__))) + File::SEPARATOR
PATH = 
File.dirname(LIBPATH) + File::SEPARATOR
VERSION = 
::YAML.load(File.read(File.join(PATH, 'VERSION.yml'))).values.join '.'
EXTERNALS_BASE = 
File.join(File::SEPARATOR, 'opt')
EXTERNAL_IDENTITIES = 
File.join(EXTERNALS_BASE, 'emissary', 'identities')
EXTERNAL_AGENTS = 
File.join(EXTERNALS_BASE, 'emissary', 'agents')
EXTERNAL_OPERATORS = 
File.join(EXTERNALS_BASE, 'emissary', 'operators')
DEFAULT_EXCHANGE = 
:direct
DAEMON_RECHECK_INTERVAL = 
10
IP_CHECK_DOMAIN = 
'checkip.dyndns.org'
IP_CHECK_URL = 
"http://#{IP_CHECK_DOMAIN}"
@@pid = 
nil

Class Method Summary collapse

Class Method Details

.call(handler, config, *args) ⇒ Object

Sets up a line of communication



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# File 'lib/emissary.rb', line 153

def call handler, config, *args
  unless handler.is_a? Class or handler.is_a? Module
    klass_name = 'Emissary::Operator::' + handler.to_s.upcase
    begin
      require_klass klass_name
    rescue LoadError => e
      begin
        require_klass Emissary::EXTERNAL_OPERATORS + '::' + handler.to_s.upcase
      #rescue LoadError
        # raise the original exception if we still haven't found the file
      #  raise e
      end
    end
    handler = klass_const klass_name
  end
  
  klass = klass_from_handler(Operator, handler, config)
  
  operator = klass.new(config, *args)
  operator.validate_config!
  block_given? and yield operator
  operator
end

.dispatch(message, config, *args) ⇒ Object

Dispatches a message to the agent specified by the message



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# File 'lib/emissary.rb', line 179

def dispatch message, config, *args
  unless message.is_a? Emissary::Message
    raise ArgumentError, "message is not an Emissary::Message" 
  end
  
  begin
    agent_type = 'Emissary::Agent::' + message.agent.to_s.capitalize
    begin
      require_klass agent_type 
    rescue LoadError => e
      begin
        require_klass Emissary::EXTERNAL_AGENTS + '::' + message.agent.to_s.capitalize
      rescue LoadError
        # raise the original exception if we still haven't found the file
        raise e
      end
    end
  rescue Exception => e
    Emissary.logger.error "Dispatcher Error: #{e.class.name}: #{e.message}\n\t#{e.backtrace.join("\n\t")}"
    message = message.error(e)
    agent_type = 'Emissary::Agent::Error'
  end
  
  handler = klass_const agent_type, true
  
  klass = klass_from_handler(Agent, handler, message, config, *args)
  
  Emissary.logger.debug " [--] Dispatching message to: #{agent_type}"
  agent = klass.new(message, config, *args)
  block_given? and yield agent
  agent
end

.generate_uuid ⇒ Object 



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# File 'lib/emissary.rb', line 143

def generate_uuid
  UUID.generate
end

.identity ⇒ Object 



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# File 'lib/emissary.rb', line 147

def identity
  @@identity ||= Emissary::Identity.instance
end

.klass_const(class_name, autoload = false) ⇒ Object 



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# File 'lib/emissary.rb', line 112

def klass_const(class_name, autoload = false)
  return class_name if class_name.is_a? Class or class_name.is_a? Module
  
  klass = Object
  
  class_name.split('::').each do |c|
    begin
      klass = klass.const_get(c.to_sym)
    rescue NameError => e 
      if autoload
        require_klass( (klass == Object ? c : "#{klass.to_s}::#{c}") )
        redo
      end
    end
  end
  
  klass.to_s == class_name ? klass : nil
end

.klass_from_handler(klass = nil, handler = nil, *args) ⇒ Object 



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# File 'lib/emissary.rb', line 76

def klass_from_handler(klass = nil, handler = nil, *args)
  klass = if handler and handler.is_a? Class and not handler.nil?
    raise ArgumentError, "must provide module or subclass of #{klass.name}" unless klass >= handler
    handler
  elsif handler.is_a? Module
    resource_name = "RESOURCE_#{handler.to_s.upcase.split('::').pop}"
    begin
      klass.const_get(resource_name)
    rescue NameError
      klass.const_set(resource_name, Class.new(klass) { include handler } )
    end
  elsif klass.nil?
    raise ArgumentError, "klass must be a valid class constant for #{name}#klass_from_handler"
  elsif handler.nil?
    raise ArgumentError, "handler must be a valid class or module"
  else
    klass
  end
  
  arity = klass.instance_method(:initialize).arity
  expected = arity >= 0 ? arity : -(arity + 1)
  if (arity >= 0 and args.size != expected) or (arity < 0 and args.size < expected)
    raise ArgumentError, "wrong number of arguments for #{klass}#initialize (#{args.size} for #{expected})"
  end
  
  klass
end

.klass_loaded?(class_name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/emissary.rb', line 104

def klass_loaded?(class_name)
  begin
    !!klass_const(class_name)
  rescue NameError
    false
  end
end

.libpath(*args) ⇒ Object

Returns the library path for the module. If any arguments are given, they will be joined to the end of the libray path using File.join.



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# File 'lib/emissary.rb', line 60

def libpath( *args )
  args.empty? ? LIBPATH : File.join(LIBPATH, args.flatten)
end

.load_klass(class_name) ⇒ Object 



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# File 'lib/emissary.rb', line 131

def load_klass(class_name)
  load libpath(*class_name.downcase.split(/::/)) + '.rb'
end

.logger ⇒ Object 



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# File 'lib/emissary.rb', line 139

def logger
  Emissary::Logger.instance
end

.path(*args) ⇒ Object

Returns the path for the module. If any arguments are given, they will be joined to the end of the path using File.join.



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# File 'lib/emissary.rb', line 68

def path( *args )
  args.empty? ? PATH : File.join(PATH, args.flatten)
end

.PID ⇒ Object 



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# File 'lib/emissary.rb', line 46

def PID
  @@pid
end

.require_klass(class_name) ⇒ Object 



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# File 'lib/emissary.rb', line 135

def require_klass(class_name)
  require libpath(*class_name.downcase.split(/::/))
end

.sublib_path(*args) ⇒ Object 



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# File 'lib/emissary.rb', line 72

def sublib_path( *args )
  args.empty? ? PATH : File.join(LIBPATH, 'emissary', args.flatten)
end

.version ⇒ Object

Returns the version string for the library.



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# File 'lib/emissary.rb', line 52

def version
  VERSION
end