class Mongo::ServerSelector::Nearest

Encapsulates specifications for selecting near servers given a list

of candidates.

@since 2.0.0

Public Instance Methods

name() click to toggle source

Get the name of the server mode type.

@example Get the name of the server mode for this preference.

preference.name

@return [ Symbol ] :nearest

@since 2.0.0

# File lib/mongo/server_selector/nearest.rb, line 33
def name
  :nearest
end
slave_ok?() click to toggle source

Whether the slaveOk bit should be set on wire protocol messages.

I.e. whether the operation can be performed on a secondary server.

@return [ true ] true

@since 2.0.0

# File lib/mongo/server_selector/nearest.rb, line 43
def slave_ok?
  true
end
tags_allowed?() click to toggle source

Whether tag sets are allowed to be defined for this server preference.

@return [ true ] true

@since 2.0.0

# File lib/mongo/server_selector/nearest.rb, line 52
def tags_allowed?
  true
end
to_mongos() click to toggle source

Convert this server preference definition into a format appropriate

for a mongos server.

@example Convert this server preference definition into a format

for mongos.
preference = Mongo::ServerSelector::Nearest.new
preference.to_mongos

@return [ Hash ] The server preference formatted for a mongos server.

@since 2.0.0

# File lib/mongo/server_selector/nearest.rb, line 67
def to_mongos
  preference = { :mode => 'nearest' }
  preference.merge!({ :tags => tag_sets }) unless tag_sets.empty?
  preference.merge!({ maxStalenessSeconds: max_staleness }) if max_staleness
  preference
end

Private Instance Methods

max_staleness_allowed?() click to toggle source
# File lib/mongo/server_selector/nearest.rb, line 92
def max_staleness_allowed?
  true
end
select(candidates) click to toggle source

Select the near servers taking into account any defined tag sets and

local threshold between the nearest server and other servers.

@example Select nearest servers given a list of candidates.

preference = Mongo::ServerSelector::Nearest.new
preference.select_server(cluster)

@return [ Array ] The nearest servers from the list of candidates.

@since 2.0.0

# File lib/mongo/server_selector/nearest.rb, line 86
def select(candidates)
  matching_servers = filter_stale_servers(candidates, primary(candidates).first)
  matching_servers = match_tag_sets(matching_servers) unless tag_sets.empty?
  near_servers(matching_servers)
end