selectable.rb in mongo-2.13.0.beta1

- old
+ new

@@ -1,6 +1,6 @@
-# Copyright (C) 2014-2019 MongoDB, Inc.
+# Copyright (C) 2014-2020 MongoDB Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
@@ -34,23 +34,29 @@
       #  nearest selection in seconds.
       # @option options [ Integer ] max_staleness The maximum replication lag,
       #   in seconds, that a secondary can suffer and still be eligible for a read.
       #   A value of -1 is treated identically to nil, which is to not
       #   have a maximum staleness.
+      # @option options [ Hash | nil ] hedge A Hash specifying whether to enable hedged
+      #   reads on the server. Hedged reads are not enabled by default. When
+      #   specifying this option, it must be in the format: { enabled: true },
+      #   where the value of the :enabled key is a boolean value.
       #
       # @raise [ Error::InvalidServerPreference ] If tag sets are specified
       #   but not allowed.
       #
       # @since 2.0.0
       def initialize(options = nil)
         options = options ? options.dup : {}
         if options[:max_staleness] == -1
           options.delete(:max_staleness)
         end
-        @options = options.freeze
-        @tag_sets = (options[:tag_sets] || []).freeze
+        @options = options
+        @tag_sets = options[:tag_sets] || []
         @max_staleness = options[:max_staleness]
+        @hedge = options[:hedge]
+
         validate!
       end
 
       # @return [ Hash ] options The options.
       attr_reader :options
@@ -62,10 +68,14 @@
       #   secondary can suffer and still be eligible for a read.
       #
       # @since 2.4.0
       attr_reader :max_staleness
 
+      # @return [ Hash | nil ] hedge The document specifying whether to enable
+      #   hedged reads.
+      attr_reader :hedge
+
       # Check equality of two server selector.
       #
       # @example Check server selector equality.
       #   preference == other
       #
@@ -73,13 +83,12 @@
       #
       # @return [ true, false ] Whether the objects are equal.
       #
       # @since 2.0.0
       def ==(other)
-        name == other.name &&
-          tag_sets == other.tag_sets &&
-            max_staleness == other.max_staleness
+        name == other.name && hedge == other.hedge &&
+          max_staleness == other.max_staleness && tag_sets == other.tag_sets
       end
 
       # Inspect the server selector.
       #
       # @example Inspect the server selector.
@@ -87,11 +96,11 @@
       #
       # @return [ String ] The inspection.
       #
       # @since 2.2.0
       def inspect
-        "#<#{self.class.name}:0x#{object_id} tag_sets=#{tag_sets.inspect} max_staleness=#{max_staleness.inspect}>"
+        "#<#{self.class.name}:0x#{object_id} tag_sets=#{tag_sets.inspect} max_staleness=#{max_staleness.inspect} hedge=#{hedge}>"
       end
 
       # Select a server from the specified cluster, taking into account
       # mongos pinning for the specified session.
       #
@@ -213,18 +222,10 @@
             # by the selector (e.g. for secondary preferred, the first
             # server may be a secondary and the second server may be primary)
             # and we should take the first server here respecting the order
             server = servers.first
 
-            if cluster.topology.single? &&
-              cluster.topology.replica_set_name &&
-              cluster.topology.replica_set_name != server.description.replica_set_name
-            then
-              msg = "Cluster topology specifies replica set name #{cluster.topology.replica_set_name}, but the server has replica set name #{server.description.replica_set_name || '<nil>'}"
-              raise Error::NoServerAvailable.new(self, cluster, msg)
-            end
-
             if session && session.starting_transaction? && cluster.sharded?
               session.pin(server)
             end
 
             return server
@@ -442,9 +443,23 @@
       def validate!
         if !@tag_sets.all? { |set| set.empty? } && !tags_allowed?
           raise Error::InvalidServerPreference.new(Error::InvalidServerPreference::NO_TAG_SUPPORT)
         elsif @max_staleness && !max_staleness_allowed?
           raise Error::InvalidServerPreference.new(Error::InvalidServerPreference::NO_MAX_STALENESS_SUPPORT)
+        end
+
+        if @hedge
+          unless hedge_allowed?
+            raise Error::InvalidServerPreference.new(Error::InvalidServerPreference::NO_HEDGE_SUPPORT)
+          end
+
+          unless @hedge.is_a?(Hash) && @hedge.key?(:enabled) &&
+              [true, false].include?(@hedge[:enabled])
+            raise Error::InvalidServerPreference.new(
+              "`hedge` value (#{hedge}) is invalid - hedge must be a Hash in the " \
+              "format { enabled: true }"
+            )
+          end
         end
       end
 
       def validate_max_staleness_support!(server)
         if @max_staleness && !server.features.max_staleness_enabled?