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 asynchronous commands 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, #options, #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?, #set_option, #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_cmd_time, #get_cmd_value, #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_stale, #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 = []
  @handshake_cmds = []
  @handshakes_mutex = Mutex.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 57

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
    @handshake_cmds = []
  end

  # Actually connect
  super()
end

#get_guid(packet) ⇒ Object 



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# File 'lib/cosmos/interfaces/linc_interface.rb', line 150

def get_guid(packet)
  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.
    guid = UUIDTools::UUID.random_create.raw
    packet.write(@fieldname_guid, guid, :RAW)
  else
    guid = packet.read(@fieldname_guid)
  end
  return guid
end

#handle_local_handshake(linc_handshake) ⇒ Object 



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# File 'lib/cosmos/interfaces/linc_interface.rb', line 250

def handle_local_handshake(linc_handshake)
  # Update the current value table for this command
  command = System.commands.packet(linc_handshake.identified_command.target_name, linc_handshake.identified_command.packet_name)
  command.received_time = linc_handshake.identified_command.received_time
  command.buffer = linc_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(linc_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(linc_handshake.identified_command)
  end
end

#handle_remote_handshake(linc_handshake) ⇒ Object 



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# File 'lib/cosmos/interfaces/linc_interface.rb', line 266

def handle_remote_handshake(linc_handshake)
  # This is a remote packet (sent from here).
  # Add to the array of handshake packet responses
  # The mutex is required by the command task due to the way it
  # first looks up the handshake before removing it.
  @handshakes_mutex.synchronize do
    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!

      # Loop through all waiting commands to see if this handshake belongs to them
      this_handshake_guid = linc_handshake.get_cmd_guid(@fieldname_guid)
      handshake_cmd_index = @handshake_cmds.index {|hsc| hsc.get_cmd_guid == this_handshake_guid}

      # If command was waiting (ie the loop above found one), then remove it from waiters and signal it
      if handshake_cmd_index
        handshake_cmd = @handshake_cmds.slice!(handshake_cmd_index)
        handshake_cmd.got_your_handshake(linc_handshake)
      else
        # No command match found!  Either it gave up and timed out or this wasn't originated from here.
        # Ignore this typically.  This case here for clarity.
      end

    else
      # Synchronous version: just pop the array (pull the command off) and send it the handshake
      handshake_cmd = @handshakes_cmds.pop
      handshake_cmd.got_your_handshake(linc_handshake)
    end # of handshaking type check
  end # @handshakes_mutex.synchronize
end

#linc_interface_command(packet) ⇒ Object 



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# File 'lib/cosmos/interfaces/linc_interface.rb', line 120

def linc_interface_command(packet)
  result = false
  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
    result = true
  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
    result = true
  end

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

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

#process_handshake_results(handshake_cmd) ⇒ Object 



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# File 'lib/cosmos/interfaces/linc_interface.rb', line 213

def process_handshake_results(handshake_cmd)
  status = handshake_cmd.handshake.handshake.read('STATUS')
  code = handshake_cmd.handshake.handshake.read('CODE')
  source = handshake_cmd.handshake.error_source

  # Handle handshake warnings and errors
  if status == "OK" and code != 0
    unless @ignored_error_codes.include? code
      Logger.warn "Warning sending command (#{code}): #{source}"
    end
  elsif status == "ERROR"
    unless @ignored_error_codes.include? code
      raise "Error sending command (#{code}): #{source}"
    end
  end
end

#read ⇒ Object 



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# File 'lib/cosmos/interfaces/linc_interface.rb', line 230

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

      # Check for a local handshake
      if handshake_packet.read('origin') == "LCL"
        handle_local_handshake(linc_handshake)
      else
        handle_remote_handshake(linc_handshake) if @handshake_enabled
      end # if handshake_packet.read('origin') == "LCL"
    end # @handshake_packet.identify?(packet.buffer(false))
  end # if packet

  return packet
end

#update_length_field(packet) ⇒ Object 



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# File 'lib/cosmos/interfaces/linc_interface.rb', line 162

def update_length_field(packet)
  length = packet.length - @length_value_offset
  packet.write(@fieldname_cmd_length, length, :RAW)
end

#wait_for_response(packet, guid) ⇒ Object 



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# File 'lib/cosmos/interfaces/linc_interface.rb', line 167

def wait_for_response(packet, guid)
  # Check the number of commands waiting for handshakes.  This is just for sanity
  # If the number of commands waiting for handshakes is very large then it can't be real
  # So raise an error.  Something has gone horribly wrong.
  if @handshake_cmds.length > MAX_CONCURRENT_HANDSHAKES
    len = @handshake_cmds.length
    @handshake_cmds = []
    raise "The number of commands waiting for handshakes to #{len}. Clearing all commands!"
  end

  # Create a handshake command object and add it to the list of commands waiting
  handshake_cmd = LincHandshakeCommand.new(@handshakes_mutex, guid)
  @handshake_cmds.push(handshake_cmd)

  # wait for that handshake. This releases the mutex so that the telemetry and other commands can start running again.
  timed_out = handshake_cmd.wait_for_handshake(@response_timeout)
  # We now have the mutex again.  This interface is blocked for the rest of the command handling,
  # which should be quick because it's just checking variables and logging.
  # We want to hold the mutex during that so that the commands get logged in order of handshake from here.

  if timed_out
    # Clean this command out of the array of items that require handshakes.
    @handshake_cmds.delete_if {|hsc| hsc == handshake_cmd}
    raise "Timeout waiting for handshake from #{System.commands.format(packet, System.targets[@target_names[0]].ignored_parameters)}"
  end

  process_handshake_results(handshake_cmd)

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

#write(packet) ⇒ Object 



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# File 'lib/cosmos/interfaces/linc_interface.rb', line 92

def write(packet)
  return if linc_interface_command(packet)
  raise "Interface not connected" unless connected?()

  # Add a GUID to the GUID field if its defined
  # A GUID means it's an asychronous packet type.
  if @fieldname_guid
    guid = get_guid(packet)
  else
    # If @fieldname_guid is not defined (syncronous) we don't care what the
    # GUID is because we're not trying to match it up with anything.
    # As soon as we get a response we free the command.
    guid = 0
  end

  # Fix the length field to handle the cases where a variable length packet
  # is defined. COSMOS does not do this automatically.
  update_length_field(packet) if @fieldname_cmd_length

  # Always take the mutex (even if we aren't handshaking)
  # We do not want any incoming telemetry to be missed because
  # it could be the handshake to this command.
  @handshakes_mutex.synchronize do
    super(packet) # Send the command
    wait_for_response(packet, guid) if @handshake_enabled
  end
end