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module Mongo
module ServerSelection
module Read
# Represents a Server Selection specification test.
#
# @since 2.0.0
class Spec
# Mapping of topology description strings to topology type classes.
#
# @since 2.0.0
TOPOLOGY_TYPES = {
'ReplicaSetNoPrimary' => Mongo::Cluster::Topology::ReplicaSet,
'ReplicaSetWithPrimary' => Mongo::Cluster::Topology::ReplicaSet,
'Sharded' => Mongo::Cluster::Topology::Sharded,
'Single' => Mongo::Cluster::Topology::Single,
'Unknown' => Mongo::Cluster::Topology::Unknown
}
# Mapping of read preference modes.
#
# @since 2.0.0
READ_PREFERENCES = {
'Primary' => :primary,
'Secondary' => :secondary,
'PrimaryPreferred' => :primary_preferred,
'SecondaryPreferred' => :secondary_preferred,
'Nearest' => :nearest,
}
# @return [ String ] description The spec description.
#
# @since 2.0.0
attr_reader :description
# @return [ Hash ] read_preference The read preference to be used for selection.
#
# @since 2.0.0
attr_reader :read_preference
# @return [ Integer ] heartbeat_frequency The heartbeat frequency to be set on the client.
#
# @since 2.4.0
attr_reader :heartbeat_frequency
# @return [ Integer ] max_staleness The max_staleness.
#
# @since 2.4.0
attr_reader :max_staleness
# @return [ Array<Hash> ] eligible_servers The eligible servers before the latency
# window is taken into account.
#
# @since 2.0.0
attr_reader :eligible_servers
# @return [ Array<Hash> ] suitable_servers The set of servers matching all server
# selection logic. May be a subset of eligible_servers and/or candidate_servers.
#
# @since 2.0.0
attr_reader :suitable_servers
# @return [ Mongo::Cluster::Topology ] type The topology type.
#
# @since 2.0.0
attr_reader :type
# Instantiate the new spec.
#
# @example Create the spec.
# Spec.new(file)
#
# @param [ String ] file The name of the file.
#
# @since 2.0.0
def initialize(file)
file = File.new(file)
@test = YAML.load(ERB.new(file.read).result)
file.close
@description = "#{@test['topology_description']['type']}: #{File.basename(file)}"
@heartbeat_frequency = @test['heartbeatFrequencyMS'] / 1000 if @test['heartbeatFrequencyMS']
@read_preference = @test['read_preference']
@read_preference['mode'] = READ_PREFERENCES[@read_preference['mode']]
@max_staleness = @read_preference['maxStalenessSeconds']
@candidate_servers = @test['topology_description']['servers']
@suitable_servers = @test['suitable_servers'] || []
@in_latency_window = @test['in_latency_window'] || []
@type = TOPOLOGY_TYPES[@test['topology_description']['type']]
end
# Whether this spec describes a replica set.
#
# @example Determine if the spec describes a replica set.
# spec.replica_set?
#
# @return [true, false] If the spec describes a replica set.
#
# @since 2.0.0
def replica_set?
type == Mongo::Cluster::Topology::ReplicaSet
end
# Does this spec expect a server to be found.
#
# @example Will a server be found with this spec.
# spec.server_available?
#
# @return [true, false] If a server will be found with this spec.
#
# @since 2.0.0
def server_available?
!in_latency_window.empty?
end
# Is the max staleness setting invalid.
#
# @example Will the max staleness setting be valid with other options.
# spec.invalid_max_staleness?
#
# @return [ true, false ] If an error will be raised by the max staleness setting.
#
# @since 2.4.0
def invalid_max_staleness?
@test['error']
end
# The subset of suitable servers that falls within the allowable latency
# window.
# We have to correct for our server selection algorithm that adds the primary
# to the end of the list for SecondaryPreferred read preference mode.
#
# @example Get the list of suitable servers within the latency window.
# spec.in_latency_window
#
# @return [ Array<Hash> ] The servers within the latency window.
#
# @since 2.0.0
def in_latency_window
if read_preference['mode'] == :secondary_preferred && primary
return @in_latency_window.push(primary).uniq
end
@in_latency_window
end
# The servers a topology would return as candidates for selection.
#
# @return [ Array<Hash> ] candidate_servers The candidate servers.
#
# @since 2.0.0
def candidate_servers
@candidate_servers.select { |s| s['type'] != 'Unknown' }
end
private
def primary
@candidate_servers.find { |s| s['type'] == 'RSPrimary' }
end
end
end
end
end
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