class Mongo::Srv::Monitor

Periodically retrieves SRV records for the cluster’s SRV URI, and sets the cluster’s server list to the SRV lookup result.

If an error is encountered during SRV lookup or an SRV record is invalid or disallowed for security reasons, a warning is logged and monitoring continues.

@api private

Constants

DEFAULT_TIMEOUT
MIN_SCAN_INTERVAL

Attributes

cluster [R]

last_result [R]

@return [ Srv::Result ] Last known SRV lookup result. Used for

determining intervals between SRV lookups, which depend on SRV DNS
records' TTL values.

options [R]

Public Class Methods

finalize (thread)

Source

# File lib/mongo/srv/monitor.rb, line 100
def self.finalize(thread)
  Proc.new do
    thread.kill
  end
end

new (cluster, **opts)

Source

# File lib/mongo/srv/monitor.rb, line 42
def initialize(cluster, **opts)
  @cluster = cluster
  unless @srv_uri = opts.delete(:srv_uri)
    raise ArgumentError, 'SRV URI is required'
  end
  @options = opts.freeze
  @resolver = Srv::Resolver.new(**opts)
  @last_result = @srv_uri.srv_result
  @stop_semaphore = Semaphore.new
end

Creates the SRV monitor.

@param [ Cluster ] cluster The cluster.

@option opts [ Float ] :timeout The timeout to use for DNS lookups. @option opts [ URI::SRVProtocol ] :srv_uri The SRV URI to monitor. @option opts [ Hash ] :resolv_options For internal driver use only.

Options to pass through to Resolv::DNS constructor for SRV lookups.

Public Instance Methods

start! ()

Source

# File lib/mongo/srv/monitor.rb, line 62
def start!
  super
  ObjectSpace.define_finalizer(self, self.class.finalize(@thread))
end

Calls superclass method Mongo::BackgroundThread#start!

Private Instance Methods

do_work ()

Source

# File lib/mongo/srv/monitor.rb, line 69
def do_work
  scan!
  @stop_semaphore.wait(scan_interval)
end

scan! ()

Source

# File lib/mongo/srv/monitor.rb, line 74
def scan!
  old_hosts = last_result.address_strs

  begin
    last_result = Timeout.timeout(timeout) do
      @resolver.get_records(@srv_uri.query_hostname)
    end
  rescue Resolv::ResolvTimeout => e
    log_warn("SRV monitor: timed out trying to resolve hostname #{@srv_uri.query_hostname}: #{e.class}: #{e}")
    return
  rescue ::Timeout::Error
    log_warn("SRV monitor: timed out trying to resolve hostname #{@srv_uri.query_hostname} (timeout=#{timeout})")
    return
  rescue Resolv::ResolvError => e
    log_warn("SRV monitor: unable to resolve hostname #{@srv_uri.query_hostname}: #{e.class}: #{e}")
    return
  end

  if last_result.empty?
    log_warn("SRV monitor: hostname #{@srv_uri.query_hostname} resolved to zero records")
    return
  end

  @cluster.set_server_list(last_result.address_strs)
end

scan_interval ()

Source

# File lib/mongo/srv/monitor.rb, line 106
def scan_interval
  if last_result.empty?
    [cluster.heartbeat_interval, MIN_SCAN_INTERVAL].min
  elsif last_result.min_ttl.nil?
    MIN_SCAN_INTERVAL
  else
    [last_result.min_ttl, MIN_SCAN_INTERVAL].max
  end
end

timeout ()

Source

# File lib/mongo/srv/monitor.rb, line 116
def timeout
  options[:timeout] || DEFAULT_TIMEOUT
end