Class: Cisco::Client::GRPC

Inherits:
Cisco::Client show all
Defined in:
lib/cisco_node_utils/client/grpc.rb,
lib/cisco_node_utils/client/grpc/client.rb

Overview

Client implementation using gRPC API for IOS XR

Instance Attribute Summary collapse

Attributes inherited from Cisco::Client

#cache_auto, #data_formats, #platform

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Cisco::Client

#cache_auto?, #cache_enable=, #cache_enable?, clients, create, filter_cli, filter_data, find_subconfig, handle_errors, #inspect, #munge_to_array, munge_to_array, register_client, silence_warnings, #supports?, to_regexp, #to_s

Constructor Details

#initialize(**kwargs) ⇒ GRPC

Returns a new instance of GRPC.



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# File 'lib/cisco_node_utils/client/grpc/client.rb', line 35

def initialize(**kwargs)
  # Defaults for gRPC:
  kwargs[:host] ||= '127.0.0.1'
  kwargs[:port] ||= 57_400
  # rubocop:disable Style/HashSyntax
  super(data_formats: [:cli],
        platform:     :ios_xr,
        **kwargs)
  # rubocop:enable Style/HashSyntax
  @config = GRPCConfigOper::Stub.new(@address, :this_channel_is_insecure)
  @exec = GRPCExec::Stub.new(@address, :this_channel_is_insecure)

  # Make sure we can actually connect
  @timeout = 10
  begin
    base_msg = 'gRPC client creation failure: '
    get(command: 'show clock')
  rescue Cisco::ClientError => e
    error 'initial connect failed: ' + e.to_s
    if e.message[/deadline exceeded/i]
      raise Cisco::ConnectionRefused, \
            base_msg + 'timed out during initial connection: ' + e.message
    end
    raise e.class, base_msg + e.message
  end

  # Let commands in general take up to 2 minutes
  @timeout = 120
end

Instance Attribute Details

#timeout ⇒ Object

Returns the value of attribute timeout.



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# File 'lib/cisco_node_utils/client/grpc/client.rb', line 33

def timeout
  @timeout
end

Class Method Details

.validate_args(**kwargs) ⇒ Object 



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# File 'lib/cisco_node_utils/client/grpc/client.rb', line 65

def self.validate_args(**kwargs)
  super
  base_msg = 'gRPC client creation failure: '
  # Connection to remote system - username and password are required
  fail TypeError, base_msg + 'username must be specified' \
    if kwargs[:username].nil?
  fail TypeError, base_msg + 'password must be specified' \
    if kwargs[:password].nil?
end

Instance Method Details

#cache_flush ⇒ Object 



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# File 'lib/cisco_node_utils/client/grpc/client.rb', line 75

def cache_flush
  @cache_hash = {
    'cli_config'           => {},
    'show_cmd_text_output' => {},
    'show_cmd_json_output' => {},
  }
end

#get(data_format: :cli, command: nil, context: nil, value: nil) ⇒ Object 



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# File 'lib/cisco_node_utils/client/grpc/client.rb', line 120

def get(data_format: :cli,
        command:     nil,
        context:     nil,
        value:       nil)
  super
  fail ArgumentError if command.nil?
  args = ShowCmdArgs.new(cli: command)
  output = req(@exec, 'show_cmd_text_output', args)
  self.class.filter_cli(cli_output: output, context: context, value: value)
end

#handle_errors(args, error_responses) ⇒ Object 



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# File 'lib/cisco_node_utils/client/grpc/client.rb', line 226

def handle_errors(args, error_responses)
  return if error_responses.empty?
  debug "#{error_responses.length} response(s) had errors:"
  error_responses.each { |r| debug "  error:\n#{r.errors}" }
  first_error = error_responses.first.errors
  # Conveniently for us, all *Reply protobufs in EMS have an errors field
  # Less conveniently, some are JSON and some are not.
  begin
    msg = JSON.parse(first_error)
    handle_json_error(msg)
  rescue JSON::ParserError
    handle_text_error(args, first_error)
  end
end

#handle_json_error(msg) ⇒ Object

Generate a CliError from a failed CliConfigReply



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# File 'lib/cisco_node_utils/client/grpc/client.rb', line 254

def handle_json_error(msg)
  # {
  #   "cisco-grpc:errors": {
  #   "error": [
  #     {
  #       "error-type": "application",
  #       "error-tag": "operation-failed",
  #       "error-severity": "error",
  #       "error-message": "....",
  #     },
  #     {
  #       ...

  # {
  #   "cisco-grpc:errors": [
  #     {
  #       "error-type": "protocol",
  #       "error-message": "Failed authentication"
  #     }
  #   ]
  # }

  msg = msg['cisco-grpc:errors']
  msg = msg['error'] unless msg.is_a?(Array)
  msg.each do |m|
    type = m['error-type']
    message = m['error-message']
    if type == 'protocol' && message == 'Failed authentication'
      fail Cisco::AuthenticationFailed, message
    elsif type == 'application'
      # Example message:
      # !! SYNTAX/AUTHORIZATION ERRORS: This configuration failed due to
      # !! one or more of the following reasons:
      # !!  - the entered commands do not exist,
      # !!  - the entered commands have errors in their syntax,
      # !!  - the software packages containing the commands are not active,
      # !!  - the current user is not a member of a task-group that has
      # !!    permissions to use the commands.
      #
      # foo
      # bar
      #
      match = /\n\n(.*)\n\n\Z/m.match(message)
      if match.nil?
        rejected = '(unknown, see error message)'
      else
        rejected = match[1].split("\n")
      end
      fail Cisco::CliError.new( # rubocop:disable Style/RaiseArgs
        rejected_input: rejected,
        clierror:       message,
      )
    else
      fail Cisco::ClientError, message
    end
  end
end

#handle_response(args, replies) ⇒ Object 



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# File 'lib/cisco_node_utils/client/grpc/client.rb', line 173

def handle_response(args, replies)
  klass = replies[0].class
  unless replies.all? { |r| r.class == klass }
    fail Cisco::ClientError, 'reply class inconsistent: ' +
      replies.map(&:class).join(', ')
  end
  debug "Handling #{replies.length} '#{klass}' reply(s):"
  case klass.to_s
  when /ShowCmdTextReply/
    replies.each { |r| debug "  output:\n#{r.output}" }
    output = replies.map(&:output).join('')
    output = handle_text_output(args, output)
  when /ShowCmdJSONReply/
    # TODO: not yet supported by server to test against
    replies.each { |r| debug "  jsonoutput:\n#{r.jsonoutput}" }
    output = replies.map(&:jsonoutput).join("\n---\n")
  when /CliConfigReply/
    # nothing to process
    output = ''
  else
    fail Cisco::ClientError, "unsupported reply class #{klass}"
  end
  debug "Success with output:\n#{output}"
  output
end

#handle_text_error(args, msg) ⇒ Object

Generate an error from a failed request



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# File 'lib/cisco_node_utils/client/grpc/client.rb', line 242

def handle_text_error(args, msg)
  if /^Disallowed commands:/ =~ msg
    fail Cisco::RequestNotSupported, msg
  else
    fail Cisco::CliError.new( # rubocop:disable Style/RaiseArgs
      rejected_input: args.cli,
      clierror:       msg,
    )
  end
end

#handle_text_output(args, output) ⇒ Object 



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# File 'lib/cisco_node_utils/client/grpc/client.rb', line 199

def handle_text_output(args, output)
  # For a successful show command, gRPC presents the output as:
  # \n--------- <cmd> ----------
  # \n<output of command>
  # \n\n

  # For an invalid CLI, gRPC presents the output as:
  # \n--------- <cmd> --------
  # \n<cmd>
  # \n<error output>
  # \n\n

  # Discard the leading whitespace, header, and trailing whitespace
  output = output.split("\n").drop(2)
  return '' if output.nil? || output.empty?

  # Now we have either [<output_line_1>, <output_line_2>, ...] or
  # [<cmd>, <error_line_1>, <error_line_2>, ...]
  if output[0].strip == args.cli.strip
    fail Cisco::CliError.new( # rubocop:disable Style/RaiseArgs
      rejected_input: args.cli,
      clierror:       output.join("\n"),
    )
  end
  output.join("\n")
end

#req(stub, type, args) ⇒ Object 



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# File 'lib/cisco_node_utils/client/grpc/client.rb', line 131

def req(stub, type, args)
  if cache_enable? && @cache_hash[type] && @cache_hash[type][args.cli]
    return @cache_hash[type][args.cli]
  end

  debug "Sending '#{type}' request:"
  if args.is_a?(ShowCmdArgs) || args.is_a?(CliConfigArgs)
    debug "  with cli: '#{args.cli}'"
  end
  output = Cisco::Client.silence_warnings do
    response = stub.send(type, args,
                         timeout:  @timeout,
                         username: @username,
                         password: @password)
    # gRPC server may split the response into multiples
    response = response.is_a?(Enumerator) ? response.to_a : [response]
    debug "Got responses: #{response.map(&:class).join(', ')}"
    # Check for errors first
    handle_errors(args, response.select { |r| !r.errors.empty? })

    # If we got here, no errors occurred
    handle_response(args, response)
  end

  @cache_hash[type][args.cli] = output if cache_enable? && !output.empty?
  return output
rescue ::GRPC::BadStatus => e
  warn "gRPC error '#{e.code}' during '#{type}' request: "
  if args.is_a?(ShowCmdArgs) || args.is_a?(CliConfigArgs)
    warn "  with cli: '#{args.cli}'"
  end
  warn "  '#{e.details}'"
  case e.code
  when ::GRPC::Core::StatusCodes::UNAVAILABLE
    raise Cisco::ConnectionRefused, "Connection refused: #{e.details}"
  when ::GRPC::Core::StatusCodes::UNAUTHENTICATED
    raise Cisco::AuthenticationFailed, e.details
  else
    raise Cisco::ClientError, e.details
  end
end

#set(data_format: :cli, context: nil, values: nil) ⇒ Object

Configure the given CLI command(s) on the device.

Parameters:

  • data_format (defaults to: :cli) —

    one of Cisco::DATA_FORMATS. Default is :cli

  • context (Array<String>) (defaults to: nil) —

    Zero or more configuration commands used to enter the desired CLI sub-mode

  • values (Array<String>) (defaults to: nil) —

    One or more commands to enter within the CLI sub-mode.



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# File 'lib/cisco_node_utils/client/grpc/client.rb', line 90

def set(data_format: :cli,
        context:     nil,
        values:      nil)
  context = munge_to_array(context)
  values = munge_to_array(values)
  super
  # IOS XR lets us concatenate submode commands together.
  # This makes it possible to guarantee we are in the correct context:
  #   context: ['foo', 'bar'], values: ['baz', 'bat']
  #   ---> values: ['foo bar baz', 'foo bar bat']
  # However, there's a special case for 'no' commands:
  #   context: ['foo', 'bar'], values: ['no baz']
  #   ---> values: ['no foo bar baz'] ---- the 'no' goes at the start
  context = context.join(' ')
  unless context.empty?
    values.map! do |cmd|
      match = cmd[/^\s*no\s+(.*)/, 1]
      if match
        cmd = "no #{context} #{match}"
      else
        cmd = "#{context} #{cmd}"
      end
      cmd
    end
  end
  # CliConfigArgs wants a newline-separated string of commands
  args = CliConfigArgs.new(cli: values.join("\n"))
  req(@config, 'cli_config', args)
end