Class: AutomateEm::HttpService

Inherits:
Object
  • Object
show all
Defined in:
lib/automate-em/service/http_service.rb

Constant Summary collapse

VERBS = 
[:get, :post, :put, :delete, :head]

Instance Method Summary collapse

Constructor Details

#initialize(parent, settings) ⇒ HttpService

Returns a new instance of HttpService.



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# File 'lib/automate-em/service/http_service.rb', line 34

def initialize(parent, settings)
	
	@config = {
		:priority_bonus => 20,
		
		
		:connect_timeout => 5,
		:inactivity_timeout => 10
		# :ssl
		# :bind
		# :proxy
	}
	@uri = URI.parse(settings.uri)
	@config[:ssl] = parent.certificates if parent.respond_to?(:certificates)
	#@connection = EventMachine::HttpRequest.new(@uri, @config)
	
	@default_request_options = {
		:wait => true,			# Wait for response
		:delay => 0,			# Delay next request by x.y seconds
		:delay_on_receive => 0,	# Delay next request after a receive by x.y seconds (only works when we are waiting for responses)
		#:emit
		:retries => 2,
		:priority => 50,
		
		#
		# EM:http related
		#
		# query
		# body
		# custom_client => block
		:path => '/',
		#file => path to file for streaming
		#query
		#
		:keepalive => true,
		:redirects => 0,
		:verb => :get,
		:stream => false,		# send chunked data
		#:stream_closed => block
		#:headers
		
		#:callback => nil,		# Alternative to the received function
		#:errback => nil,
	}
	
	
	#
	# Queues
	#
	@task_queue = EM::Queue.new			# basically we add tasks here that we want to run in a strict order
	@wait_queue = EM::Queue.new
	@send_queue = EM::PriorityQueue.new(:fifo => true) {|x,y| x < y}	# regular priority
	
	#
	# Named commands
	#	Allowing for state control
	#
	@named_commands = {}
	
	
	#
	# Locks
	#
	@received_lock = Mutex.new
	@task_lock = Mutex.new
	@status_lock = Mutex.new
	@send_monitor = Object.new.extend(MonitorMixin)
	
	
	#
	# State
	#
	@last_sent_at = 0.0
	@last_receive_at = 0.0
	
	
	#
	# Configure links between objects
	#
	@parent = parent
	@parent.setbase(self)
	@shutting_down = Atomic.new(false)
	
	
	#
	# Task event loop
	#
	@task_queue_proc = Proc.new do |task|
		if !@shutting_down.value
			EM.defer do
				begin
					@task_lock.synchronize {
						task.call
					}
				rescue => e
					AutomateEm.print_error(logger, e, {
						:message => "module #{@parent.class} in http_service.rb : error in task loop",
						:level => Logger::ERROR
					})
				ensure
					ActiveRecord::Base.clear_active_connections!
					@task_queue.pop &@task_queue_proc	# First task is ready
				end
			end
		end
	end
	@task_queue.pop &@task_queue_proc	# First task is ready
	
	
	#
	# send loop
	#
	@wait_queue_proc = Proc.new do |ignore|
		if ignore != :shutdown
					
			@send_queue.pop {|command|
				if command != :shutdown
					
					begin
						
						process = true
						if command[:name].present?
							name = command[:name]
							@named_commands[name][0].pop					# Extract the command data
							command = @named_commands[name][1]
							
							if @named_commands[name][0].empty?			# See if any more of these commands are queued
								@named_commands.delete(name)				# Delete if there are not
							else
								@named_commands[name][1] = nil			# Reset if there are
							end
							
							if command.nil?											# decide if to continue or not
								process = false
							end
						end
						
						if process
							if command[:delay] > 0.0
								delay = @last_sent_at + command[:delay] - Time.now.to_f
								if delay > 0.0
									EM.add_timer delay do
										process_send(command)
									end
								else
									process_send(command)
								end
							else
								process_send(command)
							end
						else
							process_next_send
						end
					rescue => e
						EM.defer do
							AutomateEm.print_error(logger, e, {
								:message => "module #{@parent.class} in device_connection.rb, base : error in send loop",
								:level => Logger::ERROR
							})
						end
					ensure
						ActiveRecord::Base.clear_active_connections!
						@wait_queue.pop &@wait_queue_proc
					end
					
				end
			}
		end
	end
	
	@wait_queue.push(nil)	# Don't start paused
	@wait_queue.pop &@wait_queue_proc
end

Instance Method Details

#config=(options) ⇒ Object 



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# File 'lib/automate-em/service/http_service.rb', line 545

def config= (options)
	EM.schedule do
		@config.merge!(options)
		@connection = nil
	end
end

#default_request_options=(options) ⇒ Object 



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# File 'lib/automate-em/service/http_service.rb', line 539

def default_request_options= (options)
	@status_lock.synchronize {
		@default_request_options.merge!(options)
	}
end

#do_process_response(response, command) ⇒ Object 



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# File 'lib/automate-em/service/http_service.rb', line 386

def do_process_response(response, command)
	return if @shutting_down.value
	
	result = :abort
	begin
		@parent.mark_emit_start(command[:emit]) if command[:emit].present?
		
		if command[:callback].present?
			result = command[:callback].call(response, command)
		elsif @parent.respond_to?(:received)
			result = @parent.received(response, command)
		else
			result = true
		end
	rescue => e
		#
		# save from bad user code (don't want to deplete thread pool)
		#	This error should be logged in some consistent manner
		#
		AutomateEm.print_error(logger, e, {
			:message => "module #{@parent.class} error whilst calling: received",
			:level => Logger::ERROR
		})
	ensure
		@parent.mark_emit_end if command[:emit].present?
		ActiveRecord::Base.clear_active_connections!
	end
	
	if command[:wait]
		EM.schedule do
			process_result(result, command)
		end
	end
end

#do_send_request(path, options = {}, *args, &block) ⇒ Object

Processes sends in strict order



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# File 'lib/automate-em/service/http_service.rb', line 464

def do_send_request(path, options = {}, *args, &block)
	
	begin
		@status_lock.synchronize {
			options = @default_request_options.merge(options)
		}
		options[:path] = path unless path.nil?
		options[:retries] = 0 if options[:wait] == false
		
		if options[:callback].nil? && (args.length > 0 || block.present?)
			options[:callback] = args[0] unless args.empty? || args[0].class != Proc
			options[:callback] = block unless block.nil?
		end
		
		if options[:name].present?
			options[:name] = options[:name].to_sym
		end
	rescue => e
		AutomateEm.print_error(logger, e, {
			:message => "module #{@parent.class} in device_connection.rb, send : possible bad data or options hash",
			:level => Logger::ERROR
		})
		
		return true
	end
		
		
	#
	# Use a monitor here to allow for re-entrant locking
	#	This allows for a priority queue and we guarentee order of operations
	#
	bonus = false
	begin
		@send_monitor.mon_exit
		@send_monitor.mon_enter
		bonus = true
	rescue
	end
	
	EM.schedule do
		if bonus
			options[:priority] -= @config[:priority_bonus]
		end
		
		add = true
		if options[:name].present?
			name = options[:name]
			if @named_commands[name].nil?
				@named_commands[name] = [[options[:priority]], options]	#TODO:: we need to deal with the old commands emit values!
			elsif @named_commands[name][0][-1] > options[:priority]
				@named_commands[name][0].push(options[:priority])
				@named_commands[name][1] = options						#TODO:: we need to deal with the old commands emit values!
			else
				@named_commands[name][1] = options						#TODO:: we need to deal with the old commands emit values!
				add = false
			end
		end
		
		@send_queue.push(options, options[:priority]) if add
	end
		
	return false
rescue => e
	#
	# Save from a fatal error
	#
	AutomateEm.print_error(logger, e, {
		:message => "module #{@parent.class} in device_connection.rb, send : something went terribly wrong to get here",
		:level => Logger::ERROR
	})
	return true
end

#logger ⇒ Object

Everything below here is called from a deferred thread



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# File 'lib/automate-em/service/http_service.rb', line 452

def logger
	@parent.logger
end

#on_stream_close(http, command) ⇒ Object 



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# File 'lib/automate-em/service/http_service.rb', line 351

def on_stream_close(http, command)
	if command[:stream_closed].present?
		EM.defer {
			begin
				command[:stream_closed].call(http, command)
			rescue => e
				#
				# save from bad user code (don't want to deplete thread pool)
				#	This error should be logged in some consistent manner
				#
				AutomateEm.print_error(logger, e, {
					:message => "module #{@parent.class} error whilst calling: stream closed",
					:level => Logger::ERROR
				})
			ensure
				ActiveRecord::Base.clear_active_connections!
			end
		}
	end
end

#process_next_send ⇒ Object 



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# File 'lib/automate-em/service/http_service.rb', line 345

def process_next_send
	EM.next_tick do
		@wait_queue.push(nil)	# Allows next response to process
	end
end

#process_response(response, command) ⇒ Object

Caled from receive



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# File 'lib/automate-em/service/http_service.rb', line 376

def process_response(response, command)
	EM.defer do
		@received_lock.synchronize { 	# This lock protects the send queue lock when we are emiting status
			@send_monitor.mon_synchronize {
				do_process_response(response, command)
			}
		}
	end
end

#process_result(result, command) ⇒ Object 



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# File 'lib/automate-em/service/http_service.rb', line 422

def process_result(result, command)
	if [false, :failed].include?(result) && command[:retries] > 0	# assume command failed, we need to retry
		command[:retries] -= 1
		@send_queue.push(command, command[:priority] - @config[:priority_bonus])
	end
	
	#else    result == :abort || result == :success || result == true || waits and retries exceeded
	
	if command[:delay_on_receive] > 0.0
		delay_for = (@last_receive_at + command[:delay_on_receive] - Time.now.to_f)
		
		if delay_for > 0.0
			EM.add_timer delay_for do
				process_next_send
			end
		else
			process_next_send
		end
	else
		process_next_send
	end
end

#process_send(command) ⇒ Object

this is on the reactor thread



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# File 'lib/automate-em/service/http_service.rb', line 209

def process_send(command)	# this is on the reactor thread
	begin
		if @connection.nil?
			@connection = EventMachine::HttpRequest.new(@uri, @config)
			#
			# TODO:: allow for a block to be passed in too
			#
			if @parent.respond_to?(:use_middleware)
				@parent.use_middleware(@connection)
			end
		end
		
#				if command[:custom_client].nil?
			http = @connection.__send__(command[:verb], command)
=begin				else
			http = @connection.__send__(command[:verb], command) do |*args|
				begin
					command[:custom_client].call *args
				rescue => e
					#
					# Save the thread in case of bad data in that send
					#
					EM.defer do
						AutomateEm.print_error(logger, e, {
							:message => "module #{@parent.class} in device_connection.rb, process_send : possible bad data",
							:level => Logger::ERROR
						})
					end
					
					process_next_send if command[:wait]
					
					raise e	# continue propagation
				end
=end					end
#				end
		
		@last_sent_at = Time.now.to_f
		
		if command[:stream]
			http.stream { |chunk|
				EM.defer {
					@task_queue.push lambda {
						if command[:callback].present?
							command[:callback].call(chunk, command)
						elsif @parent.respond_to?(:received)
							@parent.received(chunk, command)
						end
					}
				}
			}
			http.callback {
				#
				# streaming has finished
				#
				if logger.debug?
					EM.defer do
						logger.debug "Stream closed by remote"
					end
				end
				on_stream_close(http, command)
				if command[:wait]
					process_next_send
				end
			}
		else
			http.callback {
				process_response(http, command)
			}
		end
		
		if command[:headers].present?
			http.headers { |hash|
				EM.defer {
					@task_queue.push lambda {
						command[:headers].call(hash)
					}
				}
			}
		end
		
		if command[:wait]
			http.errback do
				@connection = nil
				
				if !command[:stream]
					process_result(:failed, command)
					
					EM.defer do
						logger.info "module #{@parent.class} error: #{http.error}"
						logger.info "A response was not received for the command: #{command[:path]}"
					end
				else
					if logger.debug?
						EM.defer do
							logger.debug "Stream connection dropped"
						end
					end
					on_stream_close(http, command)
					process_next_send
				end
			end
		elsif command[:stream]
			http.errback do
				@connection = nil
				if logger.debug?
					EM.defer do
						logger.debug "Stream connection dropped"
					end
				end
				on_stream_close(http, command)
			end
			process_next_send
		else
			http.errback do
				@connection = nil
			end
			process_next_send
		end
	rescue => e
		#
		# Save the thread in case of bad data in that send
		#
		EM.defer do
			AutomateEm.print_error(logger, e, {
				:message => "module #{@parent.class} in device_connection.rb, process_send : possible bad data",
				:level => Logger::ERROR
			})
		end
		
		process_next_send
	ensure
		@connection = nil unless command[:keepalive]
		ActiveRecord::Base.clear_active_connections!
	end
end

#received_lock ⇒ Object 



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# File 'lib/automate-em/service/http_service.rb', line 456

def received_lock
	@send_monitor		# for monitor use
end

#shutdown(system) ⇒ Object 



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# File 'lib/automate-em/service/http_service.rb', line 554

def shutdown(system)
	if @parent.leave_system(system) == 0
		@shutting_down.value = true
		@wait_queue.push(:shutdown)
		@send_queue.push(:shutdown, -32768)
		@task_queue.push(nil)
		
		EM.defer do
			begin
				if @parent.respond_to?(:on_unload)
					@task_lock.synchronize {
						@parent.on_unload
					}
				end
			rescue => e
				#
				# save from bad user code (don't want to deplete thread pool)
				#
				AutomateEm.print_error(logger, e, {
					:message => "module #{@parent.class} error whilst calling: on_unload on shutdown",
					:level => Logger::ERROR
				})
			ensure
				@parent.clear_active_timers
			end
		end
	end
end