Class: Cosmos::LincInterface

Inherits:
TcpipClientInterface show all
Defined in:
lib/cosmos/interfaces/linc_interface.rb

Overview

Interface for connecting to Ball Aerospace LINC Labview targets

Constant Summary collapse

MAX_CONCURRENT_HANDSHAKES =

The maximum number of handshake responses we can wait for at a time. We don’t ever expect to get close to this but we need to limit it to ensure the Array doesn’t grow out of control.

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Constants included from Extract

Extract::SCANNING_REGULAR_EXPRESSION

Instance Attribute Summary

Attributes inherited from Interface

#auto_reconnect, #bytes_read, #bytes_written, #connect_on_startup, #disable_disconnect, #interfaces, #name, #num_clients, #packet_log_writer_pairs, #raw_logger_pair, #read_count, #read_queue_size, #reconnect_delay, #routers, #target_names, #thread, #write_count, #write_queue_size

Instance Method Summary collapse

Methods inherited from StreamInterface

#bytes_read, #bytes_read=, #bytes_written, #bytes_written=, #connected?, #disconnect, #post_read_data, #post_read_packet, #pre_write_packet, #write_raw

Methods inherited from Interface

#connected?, #copy_to, #disconnect, #post_identify_packet, #read_allowed?, #start_raw_logging, #stop_raw_logging, #write_allowed?, #write_raw, #write_raw_allowed?

Methods included from Api

#cmd, #cmd_no_checks, #cmd_no_hazardous_check, #cmd_no_range_check, #cmd_raw, #cmd_raw_no_checks, #cmd_raw_no_hazardous_check, #cmd_raw_no_range_check, #connect_interface, #connect_router, #disable_limits, #disable_limits_group, #disconnect_interface, #disconnect_router, #enable_limits, #enable_limits_group, #get_cmd_hazardous, #get_cmd_list, #get_cmd_log_filename, #get_cmd_param_list, #get_interface_names, #get_limits, #get_limits_event, #get_limits_groups, #get_limits_set, #get_limits_sets, #get_out_of_limits, #get_overall_limits_state, #get_packet_data, #get_router_names, #get_server_message_log_filename, #get_target_list, #get_tlm_details, #get_tlm_item_list, #get_tlm_list, #get_tlm_log_filename, #get_tlm_packet, #get_tlm_values, #interface_state, #limits_enabled?, #map_target_to_interface, #router_state, #send_raw, #set_limits, #set_limits_set, #set_tlm, #set_tlm_raw, #start_cmd_log, #start_logging, #start_new_server_message_log, #start_raw_logging_interface, #start_raw_logging_router, #start_tlm_log, #stop_cmd_log, #stop_logging, #stop_raw_logging_interface, #stop_raw_logging_router, #stop_tlm_log, #subscribe_limits_events, #subscribe_packet_data, #tlm, #tlm_formatted, #tlm_raw, #tlm_variable, #tlm_with_units, #unsubscribe_limits_events, #unsubscribe_packet_data

Constructor Details

#initialize(hostname, port, handshake_enabled = true, response_timeout = 5.0, read_timeout = nil, write_timeout = 5.0, length_bitoffset = 0, length_bitsize = 16, length_value_offset = 4, fieldname_guid = 'HDR_GUID', endianness = 'BIG_ENDIAN', fieldname_cmd_length = 'HDR_LENGTH') ⇒ LincInterface

Returns a new instance of LincInterface.



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# File 'lib/cosmos/interfaces/linc_interface.rb', line 23

def initialize(
  hostname,
  port,
  handshake_enabled = true,
  response_timeout = 5.0,
  read_timeout = nil,
  write_timeout = 5.0,
  length_bitoffset = 0,
  length_bitsize = 16,
  length_value_offset = 4,
  fieldname_guid = 'HDR_GUID',
  endianness = 'BIG_ENDIAN',
  fieldname_cmd_length = 'HDR_LENGTH'
)
  # Initialize Super Class
  super(hostname, port, port, write_timeout, read_timeout, 'LENGTH',
    length_bitoffset, length_bitsize, length_value_offset, 1, endianness, 0, nil, nil)

  # Configuration Settings
  @handshake_enabled = ConfigParser.handle_true_false(handshake_enabled)
  @response_timeout  = response_timeout.to_f
  @length_value_offset = Integer(length_value_offset)
  @fieldname_guid = ConfigParser.handle_nil(fieldname_guid)
  @fieldname_cmd_length = ConfigParser.handle_nil(fieldname_cmd_length)

  # Other instance variables
  @ignored_error_codes = []
  @handshakes = []
  @handshakes_mutex = Mutex.new
  @handshakes_resource = ConditionVariable.new

  # Call this once now because the first time is slow
  UUIDTools::UUID.random_create.raw
end

Instance Method Details

#connect ⇒ Object

def initialize



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# File 'lib/cosmos/interfaces/linc_interface.rb', line 58

def connect
  # Packet definitions need to be retrieved here because @target_names is not filled in until after initialize
  @handshake_packet = System.telemetry.packet(@target_names[0], 'HANDSHAKE')
  @error_packet = System.telemetry.packet(@target_names[0], 'ERROR')

  # Handle not defining the interface configuration commands (May not want to support this functionality)
  begin
    @error_ignore_command = nil
    @error_ignore_command = System.commands.packet(@target_names[0], 'COSMOS_ERROR_IGNORE')
  rescue
  end
  begin
    @error_handle_command = nil
    @error_handle_command = System.commands.packet(@target_names[0], 'COSMOS_ERROR_HANDLE')
  rescue
  end
  begin
    @handshake_enable_command = nil
    @handshake_enable_command = System.commands.packet(@target_names[0], 'COSMOS_HANDSHAKE_EN')
  rescue
  end
  begin
    @handshake_disable_command = nil
    @handshake_disable_command = System.commands.packet(@target_names[0], 'COSMOS_HANDSHAKE_DS')
  rescue
  end

  @handshakes_mutex.synchronize do
    @handshakes = []
  end

  # Actually connect
  super()
end

#read ⇒ Object

def write



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# File 'lib/cosmos/interfaces/linc_interface.rb', line 231

def read
  packet = super()
  if packet
    if @handshake_packet.identify?(packet.buffer(false))
      handshake_packet = @handshake_packet.clone
      handshake_packet.buffer = packet.buffer
      my_handshake = LincHandshake.new(handshake_packet, @target_names[0])

      if handshake_packet.read('origin') == "LCL"
        # Update the current value table for this command
        command = System.commands.packet(my_handshake.identified_command.target_name, my_handshake.identified_command.packet_name)
        command.received_time = my_handshake.identified_command.received_time
        command.buffer = my_handshake.identified_command.buffer
        command.received_count += 1

        # Put a log of the command onto the server for the user to see
        Logger.info("External Command: " + System.commands.format(my_handshake.identified_command, System.targets[@target_names[0]].ignored_parameters))

        # Log the command to the command log(s)
        @packet_log_writer_pairs.each do |packet_log_writer_pair|
          packet_log_writer_pair.cmd_log_writer.write(my_handshake.identified_command)
        end
      else
        # This is a remote packet (sent from here).
        # Add to the array of handshake packet responses (only if handshakes are enabled).
        # The mutex is required by the command task due to the way it
        # first looks up the handshake before removing it.
        if @handshake_enabled
          @handshakes_mutex.synchronize do
            @handshakes.push(my_handshake)
            if @handshakes.length > MAX_CONCURRENT_HANDSHAKES
              len = @handshakes.length
              @handshakes = []
              raise "The handshakes response array has grown to #{len}. Clearing all handshakes!"
            end
            # Tell all waiting commands to take a look
            @handshakes_resource.broadcast
          end # @handshakes_mutex.synchronize
        end # if @handshake_enabled

      end # if handshake_packet.read('origin') == "LCL"
    end # @handshake_packet.identify?(packet.buffer(false))
  end # if packet

  return packet
end

#write(packet) ⇒ Object 



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# File 'lib/cosmos/interfaces/linc_interface.rb', line 93

def write(packet)
  ######################################
  # Commands handled in the COSMOS interface not the LINC target
  ######################################

  if @error_ignore_command and @error_ignore_command.identify?(packet.buffer(false))
    linc_cmd = @error_ignore_command.clone
    linc_cmd.buffer = packet.buffer
    code = linc_cmd.read('CODE')
    @ignored_error_codes << code unless @ignored_error_codes.include? code
    return
  end

  if @error_handle_command and @error_handle_command.identify?(packet.buffer(false))
    linc_cmd = @error_handle_command.clone
    linc_cmd.buffer = packet.buffer
    code = linc_cmd.read('CODE')
    @ignored_error_codes.delete(code) if @ignored_error_codes.include? code
    return
  end

  if @handshake_enable_command and @handshake_enable_command.identify?(packet.buffer(false))
    @handshake_enabled = true
    return
  end

  if @handshake_disable_command and @handshake_disable_command.identify?(packet.buffer(false))
    @handshake_enabled = false
    return
  end

  # Verify we are connected to the LINC target
  if connected?()
    # Add a GUID to the GUID field if its defined
    if @fieldname_guid
      if not packet.read(@fieldname_guid) =~ /[\x01-\xFF]/
        # The GUID has not been set already (it has all \x00 values), so make a new one.
        # This enables a router GUI to make the GUIDs so it can process handshakes too.
        my_guid = UUIDTools::UUID.random_create.raw
        packet.write(@fieldname_guid, my_guid, :RAW)
      else
        my_guid = packet.read(@fieldname_guid)
      end
    end

    # Fix the length field to handle the cases where a variable length packet
    # is defined. COSMOS does not do this automatically.
    if @fieldname_cmd_length
      my_length = packet.length - @length_value_offset
      packet.write(@fieldname_cmd_length, my_length, :RAW)
    end

    # Always take the mutex (even if we aren't handshaking)
    @handshakes_mutex.synchronize do

      # Send the command
      super(packet)

      # Wait for the response if handshaking
      if @handshake_enabled
        begin
          my_handshake = nil

          # The time after which we will give up waiting for a response
          deadline = Time.now + @response_timeout

          # Loop until we find our response
          while my_handshake.nil?
            # How long should we wait in this loop. We could get notified
            # multiple times for handshakes that aren't ours so we need to
            # recalculate the wait time each time.
            to_wait = deadline - Time.now

            # If there is no more time to wait then this is a timeout so we break
            # out of the loop looking for handshakes
            if to_wait <= 0
              raise "Timeout waiting for handshake from #{System.commands.format(packet, System.targets[@target_names[0]].ignored_parameters)}"
            end

            # Wait until the telemetry side signals that there is a new handshake to check or timeout.
            # This releases the mutex until the telemetry side signals us
            @handshakes_resource.wait(@handshakes_mutex, to_wait)
            # We now have the mutex again

            # Loop if we have timed out so we can handle the timeout with common code
            next if (deadline - Time.now) <= 0

            if @fieldname_guid
              # A GUID means it's an asychronous packet type.
              # So look at the list of incoming handshakes and pick off (deleting)
              # the handshake from the list if it's for this command.
              #
              # The mutex is required because the telemetry task
              # could enqueue a response between the index lookup and the slice
              # function which would remove the wrong response. FAIL!
              my_handshake_index = @handshakes.index {|hs| hs.get_cmd_guid(@fieldname_guid) == my_guid}
              my_handshake = @handshakes.slice!(my_handshake_index) if my_handshake_index
            else
              # This is the synchronous version
              my_handshake = @handshakes.pop
            end
          end # while my_handshake.nil?

          # Handle handshake warnings and errors
          if my_handshake.handshake.read('STATUS') == "OK" and my_handshake.handshake.read('CODE') != 0
            unless @ignored_error_codes.include? my_handshake.handshake.read('CODE')
              Logger.warn "Warning sending command (#{my_handshake.handshake.read('CODE')}): #{my_handshake.error_source}"
            end
          elsif my_handshake.handshake.read('STATUS') == "ERROR"
            unless @ignored_error_codes.include? my_handshake.handshake.read('CODE')
              raise "Error sending command (#{my_handshake.handshake.read('CODE')}): #{my_handshake.error_source}"
            end
          end
        rescue Exception => err
          # If anything goes wrong after successfully writing the packet to the LINC target
          # ensure that the packet gets updated in the CVT and logged to the packet log writer.
          # COSMOS normally only does this if write returns successfully
          if packet.identified?
            command = System.commands.packet(packet.target_name, packet.packet_name)
          else
            command = System.commands.packet('UNKNOWN', 'UNKNOWN')
          end
          command.buffer = packet.buffer

          @packet_log_writer_pairs.each do |packet_log_writer_pair|
            packet_log_writer_pair.cmd_log_writer.write(packet)
          end

          raise err
        end
      end # if @handshake_enabled
    end # @handshakes_mutex.synchronize
  else
    raise "Interface not connected"
  end # if connected

end