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