Class: LogStash::Inputs::Snmp

Inherits:
Base
  • Object
show all
Extended by:
PluginMixins::ValidatorSupport::FieldReferenceValidationAdapter
Includes:
PluginMixins::ECSCompatibilitySupport::TargetCheck, PluginMixins::EventSupport::EventFactoryAdapter, PluginMixins::Snmp::Common
Defined in:
lib/logstash/inputs/snmp.rb

Overview

The SNMP input plugin polls network devices using Simple Network Management Protocol (SNMP) to gather information related to the current state of the devices operation.

Defined Under Namespace

Classes: StoppableIntervalRunner

Constant Summary

Constants included from PluginMixins::Snmp::Common

PluginMixins::Snmp::Common::MIB_BASE_PATH, PluginMixins::Snmp::Common::MIB_PROVIDED_PATHS, PluginMixins::Snmp::Common::OID_MAPPING_FORMAT_DEFAULT, PluginMixins::Snmp::Common::OID_MAPPING_FORMAT_RUBY_SNMP

Instance Method Summary collapse

Methods included from PluginMixins::Snmp::Common

#build_mib_manager!, #build_snmp_client!, included

Constructor Details

#initialize(params = {}) ⇒ Snmp

Returns a new instance of Snmp.



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# File 'lib/logstash/inputs/snmp.rb', line 70

def initialize(params={})
  super(params)

  @host_protocol_field = ecs_select[disabled: '[@metadata][host_protocol]', v1: '[@metadata][input][snmp][host][protocol]']
  @host_address_field = ecs_select[disabled: '[@metadata][host_address]', v1: '[@metadata][input][snmp][host][address]']
  @host_port_field = ecs_select[disabled: '[@metadata][host_port]', v1: '[@metadata][input][snmp][host][port]']
  @host_community_field = ecs_select[disabled: '[@metadata][host_community]', v1: '[@metadata][input][snmp][host][community]']

  # Add the default "host" field to the event, for backwards compatibility, or host.ip in ecs mode
  unless params.key?('add_field')
    host_ip_field = ecs_select[disabled: "host", v1: "[host][ip]"]
    @add_field = { host_ip_field => "%{#{@host_address_field}}" }
  end
end

Instance Method Details

#close ⇒ Object 



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# File 'lib/logstash/inputs/snmp.rb', line 227

def close
  # keep this close order (aggregator, client), so the request_aggregator can gracefully shutdown
  begin
    @request_aggregator.close unless @request_aggregator.nil?
  rescue => e
    logger.warn('Error closing SNMP client request aggregator. Ignoring', :exception => e)
  end

  begin
    @client.close unless @client.nil?
  rescue => e
    logger.warn('Error closing SNMP client. Ignoring', :exception => e)
  end
end

#poll_clients(queue) ⇒ Object 



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# File 'lib/logstash/inputs/snmp.rb', line 149

def poll_clients(queue)
  max_host_timeout = 0
  in_flight_requests = []

  @client_definitions.each do |definition|
    target = @client.create_target(
      definition[:host],
      definition[:version],
      definition[:retries],
      definition[:timeout],
      definition[:host_community],
      definition[:security_name],
      definition[:security_level]
    )

    request = @request_aggregator.create_request(@client)
    in_flight_requests << { request: request, definition: definition }

    if definition[:get].any?
      request.get(target, definition[:get].map { |oid| OID.new(oid) })
    end

    definition[:walk]&.each do |oid|
      request.walk(target, OID.new(oid))
    end

    @tables&.each do |table_entry|
      oids = table_entry['columns'].map { |oid| OID.new(oid) }
      request.table(target, table_entry['name'], oids)
    end

    max_host_timeout = definition[:timeout] if definition[:timeout] > max_host_timeout
  end

  in_flight_requests.each do |req|
    definition = req[:definition]
    result_consumer = lambda do |result|
      if result&.any?
        event = targeted_event_factory.new_event(result)
        event.set(@host_protocol_field, definition[:host_protocol])
        event.set(@host_address_field, definition[:host_address])
        event.set(@host_port_field, definition[:host_port])
        event.set(@host_community_field, definition[:host_community])
        decorate(event)
        queue << event
      else
        logger.debug? && logger.debug('No SNMP data retrieved', host: definition[:host_address])
      end
    end

    req[:request].get_result_async(result_consumer)
  end

  begin
    # blocks until all requests are complete
    @request_aggregator.await(in_flight_requests.map { |p| p[:request] }, poll_hosts_timeout(max_host_timeout))
  rescue java.util.concurrent.TimeoutException => _
    logger.error("Timed out while waiting for SNMP requests to finish. Consider increasing `poll_hosts_timeout` if the number of hosts is large")
  end
end

#poll_hosts_timeout(max_host_timeout) ⇒ Object 



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# File 'lib/logstash/inputs/snmp.rb', line 210

def poll_hosts_timeout(max_host_timeout)
  return @poll_hosts_timeout if @poll_hosts_timeout

  # this timeout should be a safe-guard and it should never wait for that long.
  # It might reach this point if there are several hosts operations, the hosts
  # are unreachable/unhealthy, and/or the configured host timeout is too high.
  in_flight_timeout = 1000 * 60 * 60 # 1 hour
  in_flight_timeout = max_host_timeout if max_host_timeout > in_flight_timeout
  in_flight_timeout = @interval if @interval > in_flight_timeout

  in_flight_timeout
end

#register ⇒ Object 



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# File 'lib/logstash/inputs/snmp.rb', line 85

def register
  validate_config!

  mib_manager = build_mib_manager!

  # setup client definitions per provided host
  @client_definitions = []
  supported_transports = Set.new
  hosts_versions = Set.new

  @hosts.each do |host|
    host_name = host['host']
    version = host['version'] || '2c'

    unless version =~ VERSION_REGEX
      raise(LogStash::ConfigurationError, "only protocol version '1', '2c' and '3' are supported for host option '#{host_name}'")
    end

    host_details = host_name.match(HOST_REGEX)
    raise(LogStash::ConfigurationError, "invalid format for host option '#{host_name}'") unless host_details

    unless host_details[:host_protocol].to_s =~ /^(?:udp|tcp)$/i
      raise(LogStash::ConfigurationError, "only udp & tcp protocols are supported for host option '#{host_name}'")
    end

    host_protocol = host_details[:host_protocol]
    definition = {
      :get => Array(get),
      :walk => Array(walk),

      :host => host_name,
      :host_address => host_details[:host_address],
      :host_protocol => host_protocol,
      :host_port => host_details[:host_port],
      :host_community => host['community'] || 'public',

      :retries => host['retries'] || 2,
      :timeout => host['timeout'] || 1000,
      :version => version,

      :security_name => @security_name,
      :security_level => @security_level,
    }

    supported_transports << host_protocol
    hosts_versions << version
    @client_definitions << definition
  end

  @client = build_client!(mib_manager, supported_transports, hosts_versions)
  @request_aggregator = create_request_aggregator
end

#run(queue) ⇒ Object 



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# File 'lib/logstash/inputs/snmp.rb', line 138

def run(queue)
  # Put the client into the listen mode, so it can send requests and receive responses
  @client.listen

  # Single threaded poller which sleeps off the remaining interval between each run.
  # Each run polls all the defined hosts for the get, table and walk options.
  stoppable_interval_runner.every(@interval, 'polling hosts') do
    poll_clients(queue)
  end
end

#stoppable_interval_runner ⇒ Object 



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# File 'lib/logstash/inputs/snmp.rb', line 223

def stoppable_interval_runner
  StoppableIntervalRunner.new(self)
end