lib/mongo/cluster.rb in mongo-2.13.0.beta1 vs lib/mongo/cluster.rb in mongo-2.13.0.rc1

@@ -393,11 +393,11 @@
     #
     # @return [ Array<Server> ] The candidate servers.
     #
     # @since 2.0.0
     def servers
-      topology.servers(servers_list.compact).compact
+      topology.servers(servers_list)
     end
 
     # The addresses in the cluster.
     #
     # @example Get the addresses in the cluster.
@@ -597,15 +597,18 @@
     # @option options [ true | false ] :keep_connection_pool Usually when the
     #   new server description is unknown, the connection pool on the
     #   respective server is cleared. Set this option to true to keep the
     #   existing connection pool (required when handling not master errors
     #   on 4.2+ servers).
+    # @option aptions [ true | false ] :awaited Whether the updated description
+    #   was a result of processing an awaited ismaster.
     #
     # @api private
     def run_sdam_flow(previous_desc, updated_desc, options = {})
       @sdam_flow_lock.synchronize do
-        flow = SdamFlow.new(self, previous_desc, updated_desc)
+        flow = SdamFlow.new(self, previous_desc, updated_desc,
+          awaited: options[:awaited])
         flow.server_description_changed
 
         # SDAM flow may alter the updated description - grab the final
         # version for the purposes of broadcasting if a server is available
         updated_desc = flow.updated_desc
@@ -884,38 +887,55 @@
           Monitoring::Event::ServerClosed.new(server.address, topology)
         )
       end
     end
 
-    # Returns whether the deployment that the driver is connected to supports
-    # sessions.
+    # Raises Error::SessionsNotAvailable if the deployment that the driver
+    # is connected to does not support sessions.
     #
     # Session support may change over time, for example due to servers in the
-    # deployment being upgraded or downgraded. This method returns the
-    # current information if the client is connected to at least one data
-    # bearing server. If the client is currently not connected to any data
-    # bearing servers, this method returns the last known value for whether
-    # the deployment supports sessions.
+    # deployment being upgraded or downgraded. If the client is currently not
+    # connected to any data bearing servers, this method considers the state
+    # of session support as of when the client was last connected to at
+    # least one server. If the client has never connected to any servers,
+    # the deployment is considered to not support sessions.
     #
-    # @return [ true | false ] Whether deployment supports sessions.
     # @api private
-    def sessions_supported?
-      if topology.data_bearing_servers?
-        return !!topology.logical_session_timeout
+    def validate_session_support!
+      @state_change_lock.synchronize do
+        @sdam_flow_lock.synchronize do
+          if topology.data_bearing_servers?
+            unless topology.logical_session_timeout
+              raise_sessions_not_supported
+            end
+          end
+        end
       end
 
       # No data bearing servers known - perform server selection to try to
       # get a response from at least one of them, to return an accurate
       # assessment of whether sessions are currently supported.
       begin
         ServerSelector.get(mode: :primary_preferred).select_server(self)
-        !!topology.logical_session_timeout
+        @state_change_lock.synchronize do
+          @sdam_flow_lock.synchronize do
+            unless topology.logical_session_timeout
+              raise_sessions_not_supported
+            end
+          end
+        end
       rescue Error::NoServerAvailable
         # We haven't been able to contact any servers - use last known
-        # value for esssion support.
-        @update_lock.synchronize do
-          @sessions_supported || false
+        # value for session support.
+        @state_change_lock.synchronize do
+          @sdam_flow_lock.synchronize do
+            @update_lock.synchronize do
+              unless @sessions_supported
+                raise_sessions_not_supported
+              end
+            end
+          end
         end
       end
     end
 
     private
@@ -949,9 +969,25 @@
           if @srv_monitor
             @srv_monitor.stop!
           end
         end
       end
+    end
+
+    def raise_sessions_not_supported
+      # Intentionally using @servers instead of +servers+ here because we
+      # are supposed to be already holding the @update_lock and we cannot
+      # recursively acquire it again.
+      offending_servers = @servers.select do |server|
+        server.description.data_bearing? && server.logical_session_timeout.nil?
+      end
+      reason = if offending_servers.empty?
+        "There are no known data bearing servers (current seeds: #{@servers.map(&:address).map(&:seed).join(', ')})"
+      else
+        "The following servers have null logical session timeout: #{offending_servers.map(&:address).map(&:seed).join(', ')}"
+      end
+      msg = "The deployment that the driver is connected to does not support sessions: #{reason}"
+      raise Error::SessionsNotSupported, msg
     end
   end
 end
 
 require 'mongo/cluster/sdam_flow'